Phidgets Legacy Support - User contributions [en]

4-20mA Sensor Interface Primer

2018-10-22T19:42:19Z

Mparadis:

[[Category:Primer]]

{|
|- valign=middle
| align=center width=300px| __TOC__
| [[Image:1132_0.jpg|400px|link=]]
|}

==Introduction==

A 4-20mA sensor interface is a small device that adapts a 2-wire 4-20mA sensor's output to an analog output.

Normally, 4-20mA sensors are intended for industrial use and are difficult to use with a computer.
However, with a 4-20mA sensor interface and a Phidgets Interface Kit (or any device with an {{LinksNeeded|Analog Input port|[[Analog Input Primer]]}}), these sensors can be used as easily as an ordinary analog sensor.

==How it works==

Before understanding what the 4-20mA sensor interface does, it's useful to know how a 4-20mA sensor is different from an analog sensor.

====4-20mA Sensors====

[[Image:420Interface.png|400px|link=|thumb|Traditional setup for reading a 4-20mA sensor.<br/>[[Media:420Interface.png|Full-sized Image]]]]

4-20mA is an electrical standard for connecting sensors to a '''data acquisition device''' (DAQ). A 4-20mA sensor has two wires. One wire is used to power the sensor, and the other is a ground. The sensor sends data to the DAQ in the form of the amount of current it consumes. For example, a 4-20mA velocity sensor might consume 4mA when it is sensing zero movement, and would output 20mA when the sensor is moving at the maximum velocity it can sense. 4-20mA sensors are usually expensive and intended for industrial purposes. There are often less expensive 0-5V analog versions available.

'''Advantages of a 4-20mA Sensor:'''
* You can use longer wires with a 4-20mA sensor, since the data values are sent in the form of current rather than voltage levels that drop off with distance. However, you should ensure that the minimum voltage required to power the sensor is present at the end of the wire. To check, use a multimeter to measure the voltage across the two wires connecting to the sensor, when the sensor is measuring it's maximum value (and therefore drawing close to 20mA of current). If the voltage is higher than the minimum required voltage of the sensor (found in the sensor's data sheet), then it should be fine. Please note that twisted pair wire is the best for these long wire applications.

* 4-20mA sensors are less susceptible to electromagnetic interference (EMI) . This is because the data is sent in the form of current, which is less susceptible to EMI than voltage.

* It is easier to tell when your system has failed with a 4-20mA sensor. When a 4-20mA sensor senses its minimum value, it consumes 4mA of current. If it ever consumes zero current, it means there is a broken wire or some other failure in the system. When a 0-5V sensor fails in this way, the data line would read zero volts, which could mean it's just sensing zero.

'''Disadvantages of a 4-20mA Sensor:'''
* Usually more expensive than 0-5V analog sensors
* 4-20mA sensors are not very efficient, because they only need 4mA to function, and any additional current draw exists solely to communicate the value it is sensing

'''When to use a 4-20mA Sensor:'''
* If you already own a 4-20mA sensor and don't want to buy an analog version
* You need to use a very long wire between the sensor and the power source
* The environment has a lot of electromagnetic interference
* The sensor is only available in the 4-20mA format

====4-20mA Sensor Interface====

Now that we've covered how a 4-20mA sensor is different from a 0-5V analog sensor, the basic operation of a 4-20mA sensor interface should be clear. It simply powers the sensor and monitors the current consumption on the power line. It then converts the 4-20mA value to a 0-5V analog signal at its output.

===Basic Use===

[[Image:420InterfacePhidgets.png|400px|link=|thumb|Reading a 4-20mA sensor with Phidgets.<br/>[[Media:420InterfacePhidgets.png|Full-sized Image]]]]

Using a 4-20mA sensor interface with Phidgets is very simple. Simple connect the positive wire of the sensor to the +15V output on the 4-20mA interface, and connect the ground wire of the sensor to the ground wire of the interface. Then, the analog output of the 4-20mA interface can be read by any interface kit with an {{LinksNeeded|Analog Input port|[[Analog Input Primer]]}}, which can send the value to your computer via USB. Check the sensor's data sheet to determine how your program should interpret the data it is receiving.

<br clear="all">

====Using a 24V 4-20mA Sensor with Phidgets====

[[Image:420InterfacePhidget24V.png|400px|link=|thumb|Reading a 24-volt 4-20mA sensor with Phidgets.<br/>[[Media:420InterfacePhidget24V.png|Full-sized Image]]]]

The Phidgets 4-20mA interface can only supply the sensor with 15V. If you need to use a 24V sensor, you can still use a 4-20mA interface as long as you have an external 24V power supply. Connect the wires as shown in the diagram. The +15V terminal of the 4-20mA interface remains unused, but don't worry, the interface won't draw power that it doesn't need.

<br clear="all">

USB Webcam Primer

2018-10-22T19:41:16Z

Mparadis:

[[Category: Primer]]

{|
|- valign=middle
| align=center width=300px| __TOC__
| {{SERVER}}/images/3402_0_Web.jpg
|}

==Introduction==

Webcams come in many forms, but the USB ones usually come as UVC (USB Video Class) devices. This primer gives a very brief overview of what they are and how to use them.

==Advantages==

The advantage of UVC devices is their cross-platform compatibility, especially within the various flavours of Linux.

*[http://en.wikipedia.org/wiki/USB_video_device_class Wikpedia] gives a good overview of their levels of compatibility
* Many devices other than the Phidget webcam use the same protocol, please refer to [http://www.ideasonboard.org/uvc/#devices a compatibility list]

==Use==

A UVC device should be truly plug and play. Even on the [{{SERVER}}/products.php?product_id=1072 Phidget Single Board Computer], the drivers are already installed. You can almost immediately begin using video capture programs on your operating system to record video or pictures.

Examples include:

* Capture from Windows media players and creators
* Use iMovie on Mac OS X
* Use Cheese on Linux ({{Code|sudo apt-get install cheese}})

However, these programs are usually graphical programs which don't help if you want to use the webcam in code.

===Code===

Regardless of your platform, a good place to start is [http://docs.opencv.org/ OpenCV]. It is a library for C/C++ that focuses solely on processing images and video. It also has bindings to other languages like Python.

We also offer a programming example in C# to use the webcam:

*[{{SERVER}}/downloads/misc/MJPEGDecoder.zip C# Program]

Additional advice by operating system is below.

====Phidget SBC====

Any UVC webcam device should work interchangeably with any other UVC webcam device, So you don't have to use the Phidget one, you can find one that fits your needs.

On our Single Board Computer (SBC) page, we give an example of how to use a UVC webcam to take pictures using the SBC and OpenCV in code:
*[[OS - Phidget SBC#Taking Pictures With the Webcam|Taking Pictures with the Webcam]]

====Windows====

On Windows, [http://docs.opencv.org/ OpenCV] is your best bet.

====Linux====

On full Linux systems, you can possibly use OpenCV, though there have been some problems on standard Ubuntu distributions.<br>
Alternatively, you can use the program {{Code|streamer}} which can then be used in code:
:{{Code|sudo apt-get install streamer}}
:{{Code|streamer -c /dev/video0 -b 16 -o output.jpg}}

==Did You Know==

The UVC standard outlines more than just picture taking - it can control pan, tilt, resolution, etc depending on the functionality for your camera. This is how the Phidget SBC controls what resolution is displayed on its [[1072_User_Guide#SBC Web Interface|Web Interface]].

If you want to play with these advanced features, and you own an SBC, you can look at the scripts in {{Code|/var/www/}} on the SBC.

[[File:sbc_gs_webcam.png|link=|alt=]]

4-20mA Sensor Interface Primer

2018-10-22T19:40:22Z

Mparadis:

[[Category:Primer]]
[[USB_Webcam_Primer#test]]
{|
|- valign=middle
| align=center width=300px| __TOC__
| [[Image:1132_0.jpg|400px|link=]]
|}

==Introduction==

A 4-20mA sensor interface is a small device that adapts a 2-wire 4-20mA sensor's output to an analog output.

Normally, 4-20mA sensors are intended for industrial use and are difficult to use with a computer.
However, with a 4-20mA sensor interface and a Phidgets Interface Kit (or any device with an {{LinksNeeded|Analog Input port|[[Analog Input Primer]]}}), these sensors can be used as easily as an ordinary analog sensor.

==How it works==

Before understanding what the 4-20mA sensor interface does, it's useful to know how a 4-20mA sensor is different from an analog sensor.

====4-20mA Sensors====

[[Image:420Interface.png|400px|link=|thumb|Traditional setup for reading a 4-20mA sensor.<br/>[[Media:420Interface.png|Full-sized Image]]]]

4-20mA is an electrical standard for connecting sensors to a '''data acquisition device''' (DAQ). A 4-20mA sensor has two wires. One wire is used to power the sensor, and the other is a ground. The sensor sends data to the DAQ in the form of the amount of current it consumes. For example, a 4-20mA velocity sensor might consume 4mA when it is sensing zero movement, and would output 20mA when the sensor is moving at the maximum velocity it can sense. 4-20mA sensors are usually expensive and intended for industrial purposes. There are often less expensive 0-5V analog versions available.

'''Advantages of a 4-20mA Sensor:'''
* You can use longer wires with a 4-20mA sensor, since the data values are sent in the form of current rather than voltage levels that drop off with distance. However, you should ensure that the minimum voltage required to power the sensor is present at the end of the wire. To check, use a multimeter to measure the voltage across the two wires connecting to the sensor, when the sensor is measuring it's maximum value (and therefore drawing close to 20mA of current). If the voltage is higher than the minimum required voltage of the sensor (found in the sensor's data sheet), then it should be fine. Please note that twisted pair wire is the best for these long wire applications.

* 4-20mA sensors are less susceptible to electromagnetic interference (EMI) . This is because the data is sent in the form of current, which is less susceptible to EMI than voltage.

* It is easier to tell when your system has failed with a 4-20mA sensor. When a 4-20mA sensor senses its minimum value, it consumes 4mA of current. If it ever consumes zero current, it means there is a broken wire or some other failure in the system. When a 0-5V sensor fails in this way, the data line would read zero volts, which could mean it's just sensing zero.

'''Disadvantages of a 4-20mA Sensor:'''
* Usually more expensive than 0-5V analog sensors
* 4-20mA sensors are not very efficient, because they only need 4mA to function, and any additional current draw exists solely to communicate the value it is sensing

'''When to use a 4-20mA Sensor:'''
* If you already own a 4-20mA sensor and don't want to buy an analog version
* You need to use a very long wire between the sensor and the power source
* The environment has a lot of electromagnetic interference
* The sensor is only available in the 4-20mA format

====4-20mA Sensor Interface====

Now that we've covered how a 4-20mA sensor is different from a 0-5V analog sensor, the basic operation of a 4-20mA sensor interface should be clear. It simply powers the sensor and monitors the current consumption on the power line. It then converts the 4-20mA value to a 0-5V analog signal at its output.

===Basic Use===

[[Image:420InterfacePhidgets.png|400px|link=|thumb|Reading a 4-20mA sensor with Phidgets.<br/>[[Media:420InterfacePhidgets.png|Full-sized Image]]]]

Using a 4-20mA sensor interface with Phidgets is very simple. Simple connect the positive wire of the sensor to the +15V output on the 4-20mA interface, and connect the ground wire of the sensor to the ground wire of the interface. Then, the analog output of the 4-20mA interface can be read by any interface kit with an {{LinksNeeded|Analog Input port|[[Analog Input Primer]]}}, which can send the value to your computer via USB. Check the sensor's data sheet to determine how your program should interpret the data it is receiving.

<br clear="all">

====Using a 24V 4-20mA Sensor with Phidgets====

[[Image:420InterfacePhidget24V.png|400px|link=|thumb|Reading a 24-volt 4-20mA sensor with Phidgets.<br/>[[Media:420InterfacePhidget24V.png|Full-sized Image]]]]

The Phidgets 4-20mA interface can only supply the sensor with 15V. If you need to use a 24V sensor, you can still use a 4-20mA interface as long as you have an external 24V power supply. Connect the wires as shown in the diagram. The +15V terminal of the 4-20mA interface remains unused, but don't worry, the interface won't draw power that it doesn't need.

<br clear="all">

USB Webcam Primer

2018-10-22T19:40:03Z

Mparadis:

[[Category: Primer]]

<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>

<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>

<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
==test==
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>

{|
|- valign=middle
| align=center width=300px| __TOC__
| {{SERVER}}/images/3402_0_Web.jpg
|}

==Introduction==

Webcams come in many forms, but the USB ones usually come as UVC (USB Video Class) devices. This primer gives a very brief overview of what they are and how to use them.

==Advantages==

The advantage of UVC devices is their cross-platform compatibility, especially within the various flavours of Linux.

*[http://en.wikipedia.org/wiki/USB_video_device_class Wikpedia] gives a good overview of their levels of compatibility
* Many devices other than the Phidget webcam use the same protocol, please refer to [http://www.ideasonboard.org/uvc/#devices a compatibility list]

==Use==

A UVC device should be truly plug and play. Even on the [{{SERVER}}/products.php?product_id=1072 Phidget Single Board Computer], the drivers are already installed. You can almost immediately begin using video capture programs on your operating system to record video or pictures.

Examples include:

* Capture from Windows media players and creators
* Use iMovie on Mac OS X
* Use Cheese on Linux ({{Code|sudo apt-get install cheese}})

However, these programs are usually graphical programs which don't help if you want to use the webcam in code.

===Code===

Regardless of your platform, a good place to start is [http://docs.opencv.org/ OpenCV]. It is a library for C/C++ that focuses solely on processing images and video. It also has bindings to other languages like Python.

We also offer a programming example in C# to use the webcam:

*[{{SERVER}}/downloads/misc/MJPEGDecoder.zip C# Program]

Additional advice by operating system is below.

====Phidget SBC====

Any UVC webcam device should work interchangeably with any other UVC webcam device, So you don't have to use the Phidget one, you can find one that fits your needs.

On our Single Board Computer (SBC) page, we give an example of how to use a UVC webcam to take pictures using the SBC and OpenCV in code:
*[[OS - Phidget SBC#Taking Pictures With the Webcam|Taking Pictures with the Webcam]]

====Windows====

On Windows, [http://docs.opencv.org/ OpenCV] is your best bet.

====Linux====

On full Linux systems, you can possibly use OpenCV, though there have been some problems on standard Ubuntu distributions.<br>
Alternatively, you can use the program {{Code|streamer}} which can then be used in code:
:{{Code|sudo apt-get install streamer}}
:{{Code|streamer -c /dev/video0 -b 16 -o output.jpg}}

==Did You Know==

The UVC standard outlines more than just picture taking - it can control pan, tilt, resolution, etc depending on the functionality for your camera. This is how the Phidget SBC controls what resolution is displayed on its [[1072_User_Guide#SBC Web Interface|Web Interface]].

If you want to play with these advanced features, and you own an SBC, you can look at the scripts in {{Code|/var/www/}} on the SBC.

[[File:sbc_gs_webcam.png|link=|alt=]]

USB Webcam Primer

2018-10-22T19:38:54Z

Mparadis:

[[Category: Primer]]

<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>

<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>

----

<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>

{|
|- valign=middle
| align=center width=300px| __TOC__
| {{SERVER}}/images/3402_0_Web.jpg
|}

==Introduction==

Webcams come in many forms, but the USB ones usually come as UVC (USB Video Class) devices. This primer gives a very brief overview of what they are and how to use them.

==Advantages==

The advantage of UVC devices is their cross-platform compatibility, especially within the various flavours of Linux.

*[http://en.wikipedia.org/wiki/USB_video_device_class Wikpedia] gives a good overview of their levels of compatibility
* Many devices other than the Phidget webcam use the same protocol, please refer to [http://www.ideasonboard.org/uvc/#devices a compatibility list]

==Use==

A UVC device should be truly plug and play. Even on the [{{SERVER}}/products.php?product_id=1072 Phidget Single Board Computer], the drivers are already installed. You can almost immediately begin using video capture programs on your operating system to record video or pictures.

Examples include:

* Capture from Windows media players and creators
* Use iMovie on Mac OS X
* Use Cheese on Linux ({{Code|sudo apt-get install cheese}})

However, these programs are usually graphical programs which don't help if you want to use the webcam in code.

===Code===

Regardless of your platform, a good place to start is [http://docs.opencv.org/ OpenCV]. It is a library for C/C++ that focuses solely on processing images and video. It also has bindings to other languages like Python.

We also offer a programming example in C# to use the webcam:

*[{{SERVER}}/downloads/misc/MJPEGDecoder.zip C# Program]

Additional advice by operating system is below.

====Phidget SBC====

Any UVC webcam device should work interchangeably with any other UVC webcam device, So you don't have to use the Phidget one, you can find one that fits your needs.

On our Single Board Computer (SBC) page, we give an example of how to use a UVC webcam to take pictures using the SBC and OpenCV in code:
*[[OS - Phidget SBC#Taking Pictures With the Webcam|Taking Pictures with the Webcam]]

====Windows====

On Windows, [http://docs.opencv.org/ OpenCV] is your best bet.

====Linux====

On full Linux systems, you can possibly use OpenCV, though there have been some problems on standard Ubuntu distributions.<br>
Alternatively, you can use the program {{Code|streamer}} which can then be used in code:
:{{Code|sudo apt-get install streamer}}
:{{Code|streamer -c /dev/video0 -b 16 -o output.jpg}}

==Did You Know==

The UVC standard outlines more than just picture taking - it can control pan, tilt, resolution, etc depending on the functionality for your camera. This is how the Phidget SBC controls what resolution is displayed on its [[1072_User_Guide#SBC Web Interface|Web Interface]].

If you want to play with these advanced features, and you own an SBC, you can look at the scripts in {{Code|/var/www/}} on the SBC.

[[File:sbc_gs_webcam.png|link=|alt=]]

USB Webcam Primer

2018-10-22T19:38:11Z

Mparadis:

[[Category: Primer]]

<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>

<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>
<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
Java=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
VB.Net=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>

{|
|- valign=middle
| align=center width=300px| __TOC__
| {{SERVER}}/images/3402_0_Web.jpg
|}

==Introduction==

Webcams come in many forms, but the USB ones usually come as UVC (USB Video Class) devices. This primer gives a very brief overview of what they are and how to use them.

==Advantages==

The advantage of UVC devices is their cross-platform compatibility, especially within the various flavours of Linux.

*[http://en.wikipedia.org/wiki/USB_video_device_class Wikpedia] gives a good overview of their levels of compatibility
* Many devices other than the Phidget webcam use the same protocol, please refer to [http://www.ideasonboard.org/uvc/#devices a compatibility list]

==Use==

A UVC device should be truly plug and play. Even on the [{{SERVER}}/products.php?product_id=1072 Phidget Single Board Computer], the drivers are already installed. You can almost immediately begin using video capture programs on your operating system to record video or pictures.

Examples include:

* Capture from Windows media players and creators
* Use iMovie on Mac OS X
* Use Cheese on Linux ({{Code|sudo apt-get install cheese}})

However, these programs are usually graphical programs which don't help if you want to use the webcam in code.

===Code===

Regardless of your platform, a good place to start is [http://docs.opencv.org/ OpenCV]. It is a library for C/C++ that focuses solely on processing images and video. It also has bindings to other languages like Python.

We also offer a programming example in C# to use the webcam:

*[{{SERVER}}/downloads/misc/MJPEGDecoder.zip C# Program]

Additional advice by operating system is below.

====Phidget SBC====

Any UVC webcam device should work interchangeably with any other UVC webcam device, So you don't have to use the Phidget one, you can find one that fits your needs.

On our Single Board Computer (SBC) page, we give an example of how to use a UVC webcam to take pictures using the SBC and OpenCV in code:
*[[OS - Phidget SBC#Taking Pictures With the Webcam|Taking Pictures with the Webcam]]

====Windows====

On Windows, [http://docs.opencv.org/ OpenCV] is your best bet.

====Linux====

On full Linux systems, you can possibly use OpenCV, though there have been some problems on standard Ubuntu distributions.<br>
Alternatively, you can use the program {{Code|streamer}} which can then be used in code:
:{{Code|sudo apt-get install streamer}}
:{{Code|streamer -c /dev/video0 -b 16 -o output.jpg}}

==Did You Know==

The UVC standard outlines more than just picture taking - it can control pan, tilt, resolution, etc depending on the functionality for your camera. This is how the Phidget SBC controls what resolution is displayed on its [[1072_User_Guide#SBC Web Interface|Web Interface]].

If you want to play with these advanced features, and you own an SBC, you can look at the scripts in {{Code|/var/www/}} on the SBC.

[[File:sbc_gs_webcam.png|link=|alt=]]

4-20mA Sensor Interface Primer

2018-10-22T19:34:13Z

Mparadis:

[[Category:Primer]]
[[USB_Webcam_Primer#Code]]
{|
|- valign=middle
| align=center width=300px| __TOC__
| [[Image:1132_0.jpg|400px|link=]]
|}

==Introduction==

A 4-20mA sensor interface is a small device that adapts a 2-wire 4-20mA sensor's output to an analog output.

Normally, 4-20mA sensors are intended for industrial use and are difficult to use with a computer.
However, with a 4-20mA sensor interface and a Phidgets Interface Kit (or any device with an {{LinksNeeded|Analog Input port|[[Analog Input Primer]]}}), these sensors can be used as easily as an ordinary analog sensor.

==How it works==

Before understanding what the 4-20mA sensor interface does, it's useful to know how a 4-20mA sensor is different from an analog sensor.

====4-20mA Sensors====

[[Image:420Interface.png|400px|link=|thumb|Traditional setup for reading a 4-20mA sensor.<br/>[[Media:420Interface.png|Full-sized Image]]]]

4-20mA is an electrical standard for connecting sensors to a '''data acquisition device''' (DAQ). A 4-20mA sensor has two wires. One wire is used to power the sensor, and the other is a ground. The sensor sends data to the DAQ in the form of the amount of current it consumes. For example, a 4-20mA velocity sensor might consume 4mA when it is sensing zero movement, and would output 20mA when the sensor is moving at the maximum velocity it can sense. 4-20mA sensors are usually expensive and intended for industrial purposes. There are often less expensive 0-5V analog versions available.

'''Advantages of a 4-20mA Sensor:'''
* You can use longer wires with a 4-20mA sensor, since the data values are sent in the form of current rather than voltage levels that drop off with distance. However, you should ensure that the minimum voltage required to power the sensor is present at the end of the wire. To check, use a multimeter to measure the voltage across the two wires connecting to the sensor, when the sensor is measuring it's maximum value (and therefore drawing close to 20mA of current). If the voltage is higher than the minimum required voltage of the sensor (found in the sensor's data sheet), then it should be fine. Please note that twisted pair wire is the best for these long wire applications.

* 4-20mA sensors are less susceptible to electromagnetic interference (EMI) . This is because the data is sent in the form of current, which is less susceptible to EMI than voltage.

* It is easier to tell when your system has failed with a 4-20mA sensor. When a 4-20mA sensor senses its minimum value, it consumes 4mA of current. If it ever consumes zero current, it means there is a broken wire or some other failure in the system. When a 0-5V sensor fails in this way, the data line would read zero volts, which could mean it's just sensing zero.

'''Disadvantages of a 4-20mA Sensor:'''
* Usually more expensive than 0-5V analog sensors
* 4-20mA sensors are not very efficient, because they only need 4mA to function, and any additional current draw exists solely to communicate the value it is sensing

'''When to use a 4-20mA Sensor:'''
* If you already own a 4-20mA sensor and don't want to buy an analog version
* You need to use a very long wire between the sensor and the power source
* The environment has a lot of electromagnetic interference
* The sensor is only available in the 4-20mA format

====4-20mA Sensor Interface====

Now that we've covered how a 4-20mA sensor is different from a 0-5V analog sensor, the basic operation of a 4-20mA sensor interface should be clear. It simply powers the sensor and monitors the current consumption on the power line. It then converts the 4-20mA value to a 0-5V analog signal at its output.

===Basic Use===

[[Image:420InterfacePhidgets.png|400px|link=|thumb|Reading a 4-20mA sensor with Phidgets.<br/>[[Media:420InterfacePhidgets.png|Full-sized Image]]]]

Using a 4-20mA sensor interface with Phidgets is very simple. Simple connect the positive wire of the sensor to the +15V output on the 4-20mA interface, and connect the ground wire of the sensor to the ground wire of the interface. Then, the analog output of the 4-20mA interface can be read by any interface kit with an {{LinksNeeded|Analog Input port|[[Analog Input Primer]]}}, which can send the value to your computer via USB. Check the sensor's data sheet to determine how your program should interpret the data it is receiving.

<br clear="all">

====Using a 24V 4-20mA Sensor with Phidgets====

[[Image:420InterfacePhidget24V.png|400px|link=|thumb|Reading a 24-volt 4-20mA sensor with Phidgets.<br/>[[Media:420InterfacePhidget24V.png|Full-sized Image]]]]

The Phidgets 4-20mA interface can only supply the sensor with 15V. If you need to use a 24V sensor, you can still use a 4-20mA interface as long as you have an external 24V power supply. Connect the wires as shown in the diagram. The +15V terminal of the 4-20mA interface remains unused, but don't worry, the interface won't draw power that it doesn't need.

<br clear="all">

USB Webcam Primer

2018-10-22T19:30:01Z

Mparadis:

USB Webcam Primer

2018-10-22T19:26:14Z

Mparadis:

[[Category: Primer]]

<tabber>
C#=
<div class="source">
<syntaxhighlight lang=csharp>
using Phidgets;
using Phidgets.Events;
</syntaxhighlight>
</div>
|-|
tab2=
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
|-|
tab3=
<div class="source">
<syntaxhighlight lang=vbnet>
Public Class Form1
'The Phidget object declaration

Dim WithEvents ifKit As Phidgets.InterfaceKit

'... Form1_Load and Form1_OnClosing here
End Class
</syntaxhighlight>
</div>
</tabber>

{|
|- valign=middle
| align=center width=300px| __TOC__
| {{SERVER}}/images/3402_0_Web.jpg
|}

==Introduction==

Webcams come in many forms, but the USB ones usually come as UVC (USB Video Class) devices. This primer gives a very brief overview of what they are and how to use them.

==Advantages==

The advantage of UVC devices is their cross-platform compatibility, especially within the various flavours of Linux.

*[http://en.wikipedia.org/wiki/USB_video_device_class Wikpedia] gives a good overview of their levels of compatibility
* Many devices other than the Phidget webcam use the same protocol, please refer to [http://www.ideasonboard.org/uvc/#devices a compatibility list]

==Use==

A UVC device should be truly plug and play. Even on the [{{SERVER}}/products.php?product_id=1072 Phidget Single Board Computer], the drivers are already installed. You can almost immediately begin using video capture programs on your operating system to record video or pictures.

Examples include:

* Capture from Windows media players and creators
* Use iMovie on Mac OS X
* Use Cheese on Linux ({{Code|sudo apt-get install cheese}})

However, these programs are usually graphical programs which don't help if you want to use the webcam in code.

===Code===

Regardless of your platform, a good place to start is [http://docs.opencv.org/ OpenCV]. It is a library for C/C++ that focuses solely on processing images and video. It also has bindings to other languages like Python.

We also offer a programming example in C# to use the webcam:

*[{{SERVER}}/downloads/misc/MJPEGDecoder.zip C# Program]

Additional advice by operating system is below.

====Phidget SBC====

Any UVC webcam device should work interchangeably with any other UVC webcam device, So you don't have to use the Phidget one, you can find one that fits your needs.

On our Single Board Computer (SBC) page, we give an example of how to use a UVC webcam to take pictures using the SBC and OpenCV in code:
*[[OS - Phidget SBC#Taking Pictures With the Webcam|Taking Pictures with the Webcam]]

====Windows====

On Windows, [http://docs.opencv.org/ OpenCV] is your best bet.

====Linux====

On full Linux systems, you can possibly use OpenCV, though there have been some problems on standard Ubuntu distributions.<br>
Alternatively, you can use the program {{Code|streamer}} which can then be used in code:
:{{Code|sudo apt-get install streamer}}
:{{Code|streamer -c /dev/video0 -b 16 -o output.jpg}}

==Did You Know==

The UVC standard outlines more than just picture taking - it can control pan, tilt, resolution, etc depending on the functionality for your camera. This is how the Phidget SBC controls what resolution is displayed on its [[1072_User_Guide#SBC Web Interface|Web Interface]].

If you want to play with these advanced features, and you own an SBC, you can look at the scripts in {{Code|/var/www/}} on the SBC.

[[File:sbc_gs_webcam.png|link=|alt=]]

USB Webcam Primer

2018-10-22T19:23:57Z

Mparadis:

[[Category: Primer]]

<tabber>
tab1=Some neat text here
|-|
tab2=
[http://www.google.com Google]<br>
[http://www.cnn.com Cnn]<br>
|-|
tab3={{Template:SomeTemplate}}
</tabber>

{|
|- valign=middle
| align=center width=300px| __TOC__
| {{SERVER}}/images/3402_0_Web.jpg
|}

==Introduction==

Webcams come in many forms, but the USB ones usually come as UVC (USB Video Class) devices. This primer gives a very brief overview of what they are and how to use them.

==Advantages==

The advantage of UVC devices is their cross-platform compatibility, especially within the various flavours of Linux.

*[http://en.wikipedia.org/wiki/USB_video_device_class Wikpedia] gives a good overview of their levels of compatibility
* Many devices other than the Phidget webcam use the same protocol, please refer to [http://www.ideasonboard.org/uvc/#devices a compatibility list]

==Use==

A UVC device should be truly plug and play. Even on the [{{SERVER}}/products.php?product_id=1072 Phidget Single Board Computer], the drivers are already installed. You can almost immediately begin using video capture programs on your operating system to record video or pictures.

Examples include:

* Capture from Windows media players and creators
* Use iMovie on Mac OS X
* Use Cheese on Linux ({{Code|sudo apt-get install cheese}})

However, these programs are usually graphical programs which don't help if you want to use the webcam in code.

===Code===

Regardless of your platform, a good place to start is [http://docs.opencv.org/ OpenCV]. It is a library for C/C++ that focuses solely on processing images and video. It also has bindings to other languages like Python.

We also offer a programming example in C# to use the webcam:

*[{{SERVER}}/downloads/misc/MJPEGDecoder.zip C# Program]

Additional advice by operating system is below.

====Phidget SBC====

Any UVC webcam device should work interchangeably with any other UVC webcam device, So you don't have to use the Phidget one, you can find one that fits your needs.

On our Single Board Computer (SBC) page, we give an example of how to use a UVC webcam to take pictures using the SBC and OpenCV in code:
*[[OS - Phidget SBC#Taking Pictures With the Webcam|Taking Pictures with the Webcam]]

====Windows====

On Windows, [http://docs.opencv.org/ OpenCV] is your best bet.

====Linux====

On full Linux systems, you can possibly use OpenCV, though there have been some problems on standard Ubuntu distributions.<br>
Alternatively, you can use the program {{Code|streamer}} which can then be used in code:
:{{Code|sudo apt-get install streamer}}
:{{Code|streamer -c /dev/video0 -b 16 -o output.jpg}}

==Did You Know==

The UVC standard outlines more than just picture taking - it can control pan, tilt, resolution, etc depending on the functionality for your camera. This is how the Phidget SBC controls what resolution is displayed on its [[1072_User_Guide#SBC Web Interface|Web Interface]].

If you want to play with these advanced features, and you own an SBC, you can look at the scripts in {{Code|/var/www/}} on the SBC.

[[File:sbc_gs_webcam.png|link=|alt=]]

Language - Visual Basic for Applications

2018-07-31T18:00:23Z

Mparadis: /* Use Our Examples */

[[Category:Language]]
{{OSLang|[[File:Icon-Visual Basic for Applications.png|64x64px|alt=|link=]]|'''Visual Basic for Applications''' ('''VBA''') is an implementation of [http://msdn.microsoft.com/en-ca/office Microsoft]'s event-driven programming language [[Language_-_Visual_Basic_6.0|Visual Basic 6.0]] and its associated integrated development environment (IDE), which are built into most [http://office.microsoft.com Microsoft Office] applications.}}

==Introduction==

{{LanguageSupport|Visual Basic for Applications|the complete Phidget API, including events|Accelerometer (not Spatial), Encoder, InterfaceKit, RFID, TemperatureSensor and Servo.|Microsoft Office on Windows|}}

==Quick Downloads==

{{QuickDownloads|Visual Basic for Applications|
{{APIQuickDownloads|{{SERVER}}/documentation/COM_API_Manual.pdf .COM}}|
''Note: Example code is programmed to run in Microsoft Excel.''
{{ExampleQuickDownloads|{{SERVER}}/downloads/phidget21/examples/com/VBA.zip|}}|
{{WindowsQuickDownloads}}}}

==Getting Started with Visual Basic for Applications (VBA)==

If you are new to writing code for Phidgets, we recommend starting by running, then modifying existing examples. This will allow you to:
{{ExampleCodeReasons}}

Support for VBA is only on [[#Windows(2000/XP/Vista/7)|Windows 2000 / XP / Vista / 7]].

==Windows (XP/Vista/7/8)==

For a description of the Phidget library files, please see the main [[OS - Windows|Windows page]].

The Phidget examples were written using Microsoft Excel 2000 and this tutorial assumes its use. Other environments such as Microsoft Office should work provided they support VBA, and each would be set up in a similar manner.

===Use Our Examples===

First, open the command prompt in administrator mode and type the following command:

<code>
regsvr32 "C:\Progarm Files\Phidgets\Phidget21COM.dll"
</code>

If you installed the Phidgets libraries in a different location, you'll have to modify the command.

Then, download and unpack the [{{SERVER}}/downloads/phidget21/examples/com/VBA.zip VBA Examples]. Here you will find an example called HelloWorld which is a simple, high-level example which will work with any Phidget device. You will also find specific, in-depth examples for some of our other devices. {{FindYourDevice}}

The easiest example to start with is the HelloWorld example. Find it in the unpacked examples folder:

[[Image:Vba openexample.png|border|link=|alt=]]

And then double click on it to open it in Excel. It contains Macros, so you may get a message that you can't run the program without changing your security settings. The settings can be found in Office XP under Tools → Options → Security (tab). Then you can set the security level to Medium so you can choose to run the Phidget Examples:

[[Image:Vba_setsecurity.png|link=|alt=]]

This will bring up the example itself. Hello and goodbye messages are printed to the screen as Phidgets are plugged in (attached) and unplugged (detached). Here, we plugged a Phidget Interface Kit in:

[[Image:Vba_runhelloworld.png|link=|alt=]]

===Write Your Own Code===

To begin, launch Excel with a new workbook for our project. Launch the VBA editor (Tools | Macro | Visual Basic Editor) and open “ThisWorkbook” in the navigator.

Before you can use the Phidget in your code, you must include the library in your project. This can be accomplished from the references screen (Tools | References...) by checking the box beside “Phidget Library 2.1”, or by browsing to the location the framework was installed and choosing the Phidget21COM.dll.

Afterwards, the Phidget object will need to be declared and then initialized inside the new workbook (“ThisWorkbook”). For example, we can declare and create a PhidgetInterfaceKit at the top of the code with:

<div class="source"><syntaxhighlight lang=vb>
Public WithEvents phid As PhidgetInterfaceKit
Private Sub Workbook_Open()
Set phid = New PhidgetInterfaceKit
End Sub
</syntaxhighlight></div>

The object name for any type of Phidget is listed in the API manual. Each Phidget (Spatial, Temperature Sensor, Motor Controller, Interface Kit) has a different software object named similarly to its own name. If you are not sure what the software object for your device is, find your Phidget on our [{{SERVER}} webpage], and then check the API documentation for it. Every type of Phidget also inherits functionality from the Phidget base class.

You can now play around with the examples and basic code, and when you are ready to begin writing your project you can go through our instructional section on what [[#Follow The Examples|code is in the examples]].

==Follow The Examples==

By following the instructions above, you probably now have a working example and want to understand it better so you can change it to do what you want. This teaching section has resources for you to learn from the examples and write your own.

Your main reference for writing VBA code will be our .COM API information, with syntax for all of our functions:

{{UsingAPhidgetInCodeGeneral|both of which are available in VBA|[{{SERVER}}/documentation/COM_API_Manual.pdf .COM API]}}

===Code Snippets===

Specific calls in VBA will differ in syntax from those on the [[General Phidget Programming]] page, but the concepts stay the same.

It may help to have the [[General Phidget Programming]] page and this section open at the same time, because they parallel each other and you can refer to the .COM/VBA syntax. However, ''many'' additional concepts are covered on the General Phidget Programming page on a high level, such as using multiple Phidgets, handling errors, and different styles of programming.

====Step One: Initialize and Open====

Be sure you have set up access to your Phidget in the section [[#Write Your Own Code|Write Your Own Code]]. That section also includes an initialization of the Phidget, i.e. a creation of the variable (phid) that will allow access to our Phidget, in this case an Interface Kit:

<div class="source"><syntaxhighlight lang=vb>
Public WithEvents phid As PhidgetInterfaceKit
Private Sub Workbook_Open()
Set phid = New PhidgetInterfaceKit
End Sub
</syntaxhighlight></div>

Also within that Sub, we can open the new Phidget variable:

<div class="source"><syntaxhighlight lang=vb>
phid.Open
</syntaxhighlight></div>

Open will continuously try to connect to a Phidget, based on the parameters given, even trying to reconnect if it gets disconnected. There are many different forms of open - by serial number, or even over a network using the [[Phidget WebService]]. You can check the .COM API manual for all the types of open available and how to use them.

One important thing to remember is that when working with Phidgets, a local connection will reserve the device until closed. This prevents any other instances from retrieving data from the Phidget, including other programs. The one connection per device limit does not apply when exclusively using the Phidget WebService.

====Step Two: Wait for Attachment (plugging in) of the Phidget====

To use the Phidget, it must be plugged in (attached). This means that simply calling open does not guarantee you can use the Phidget immediately. We can handle this by using event driven programming and tracking the AttachEvents and DetachEvents, or we can handle this by calling waitForAttachment. This function works for any Phidget. WaitForAttachment will block indefinitely until a connection is made to the Phidget, or an optional timeout is exceeded:

<div class="source"><syntaxhighlight lang=vb>
phid.WaitForAttachment(3000)
</syntaxhighlight></div>

====Step Three: Do Things with the Phidget====

We recommend the use of event driven programming when working with Phidgets. In Visual Basic, we hook an event handler with the following code:

<div class="source"><syntaxhighlight lang=vb>
Private Sub phid_OnSensorChange(ByVal Index As Long, ByVal SensorValue As Long)
Range("A2").Select
ActiveCell.Offset(Index, 0).Value = SensorValue
End Sub
</syntaxhighlight></div>

With this method, the code inside onSensorChange will get executed every time the - in this case - Interface Kit reports a change on one of its analog inputs. You can let the editor generate the procedure declaration for you through the drop down menu at the top of the code window.

Some events such as Attach and Detach belong to the base Phidget object and thus are common to all types of Phidgets. Other events, such as this one to read a sensor change, are specific to the type of Phidget (for example, a Temperature Sensor would have a temperature change event). Please refer to the API manual for a full list of events and their usage.

Some values can be directly read and set on the Phidget, and inside polling loops used as an alternative to event driven programming. Simply use the instance properties such as SensorValue(Index as Long) or OutputState(Index as Long) for Interface Kits:

<div class="source"><syntaxhighlight lang=vb>
phid.OutputState(4) = True
</syntaxhighlight></div>

====Step Four: Close and Delete====

At the end of your program, don’t forget to call close to free any locks on the Phidget:

<div class="source"><syntaxhighlight lang=vb>
Private Sub Workbook_BeforeClose(Cancel As Boolean)
phid.Close
End Sub
</syntaxhighlight></div>

{{MoreHowTos}}

==Common Problems and Solutions/Workarounds==

None at this time.

Language - Python Linux Terminal

2018-07-06T20:00:30Z