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The Making of our WebCam

More and more people are asking us how to build a WebCam.
This is how we did it:

 
Deti with his do-it-your-self box...
In the Beginning...
... there was Deti looking at a box containing old electronic parts. This unfortunately was not sufficient for a webcam, so he was looking for some useful things to speed up the development: 
  • A small and cheap digital camera with a computer interface.
  • A mechanical solution to install the camera outside.
  • A helpful hand: Chris, dh1mcp
The Camera

We chose a Kodak DC20 camera, which you can buy in every electronic store for about DM300.-. Because this camera is one of the first digitals, you will also get it second hand, as we did. 

The camera normally works with a 3V lithium battery and is able to store up to 16 pictures in its internal flash memory.
For downloading the pictures into a computer the camera provides a normal RS232 interface,

Kodak DC20 camera ...
The Modifications

First an external 3 volt powersupply was built using a LM 317 voltage regulator. This regulator was placed on a little PCB right next to the camera. As you can see we are using a little sheet metal for cooling the electronic component. This sheet metal is our aircondition because in normal operation its temperature is +25°C. So when the camera is installed outside in a box this prevents it from freezing (don't lough you really have to care for such things!).
Further we modified the camera's powerswitch, so that the camera automatically switchs on after connecting the power supply.

 

The Case

It is very important choosing a stable and watertight case because the reliability of the camera depends on it. We were using  a Bopla Euromas case which is available from Conrad Electronic (order #523437-44) and measures160 x 80 x 55 mm.  A plexiglas window was placed on the front of the case so that the camera can look through (how else?). To keep the box again watertight we were using a normal silicone sealant (like used for sanitary installations).

Chris looking through the window...
Camera in the case...
Fitting all together...

Now the camera has to be installed into its case. As you can see in the lower right edge of the box there is a normal 4 wire telephone cable put through a sealing ring. This cable supplies the camera with +12 volts, ground and the two serial communcation lines RX-/TX-Data. The Kodak DC20 Camera is using a normal 3,5mm stereo plug for its serial port (which is placed in the lower right edge of the camera).


  
A real blowjob...

Whenever you have to explain your kids what this phrase means simply tell them: it is done to test the sealing. The picture shows Deti blowing heavily into the case to test if there is a leak. Sure we could have done this in a more professional way but we would have had less fun. After we were sure there is everything ok we drilled a little hole (2mm) into the bottom of the case. This hole is important because of the aircondition: Since there is once humditiy inside the case there must be a posibility for letting out the condensed water (Never believe that your case is 100% sealed!).

A real blowjob...
The Interface-Box

We built a little interface to prevent the computer from being damaged by static charges. A distant thunderstorm could be enough to kill a serial port controller!

The box now is connected to the computer which runs under linux. If you are looking for some software which serves the camera's functions. Have a look on our ftp server or click here to get  dc20.tgz .

 

The interface... The box contains two special optocouplers (CNY 66) which should insulate up to 15kV. To regain the +/-12 volts after the couplers (which the camera really needs for serial communication) we were using normal MAX232 TTL to RS232 level converters.

 
The interfacebox and cameracase
Almost finished

The picture on the left shows the interface-box and the camera in its case. Now we have to care for some further mechanical matters:

  • The camera needs to have a sun protection shade.
  • The case has to be mounted somehow on a mast.
Ok, now lets go to Fachhochschule munich (which is a kind of university) to install the camera.

 
The Installation
It was a cold winterday on january 29th. The following pictures show the installation procedure of our WebCam. The picture right below this text shows chris finalizing the installation.

Chris still installing the WebCam

On the right can see Deti on the roof of FHM ready to install the camera at the mast left to him. The camera was installed on this mast because it is on a rotor so that the camera can take pictures of the hole city. In case you are interested to see what else is on this roof simply click here.

Chris installing the camera...

After this afternoon on the roof Chris was freezing but very happy about our new achievement.

The roof of FHM...

And finally Deti would like to thank
Johannes Kneip, DG3RBU for donating the camera.
Chris, DH1MCP for the good ideas and lots of help.
Fachhochschule Munich for making possible such projects.
All contributors of the DC20 resources in the internet.





http://www.lrr.in.tum.de/~fliegl/misc/webcam/index.html
© 30.03.2007 D. Fliegl