At the Second Story media lab we find our selves utilizing computer vision software for a lot of our interactive projects. When it comes to prototyping these projects we need a robust hardware solution but at a minimal cost. Enter the Infrared web cam hack. This is a common hack amongst the DIY community so we would like to share our approach to it.
To begin we need to gather materials.
– Camera: Logitech QuickCam USB web cam.
We use the Logitech camera for our hack but the same principles apply to any web cam.
– Filter: Kodak Wratten gelatin Filter IR No.87
We chose this filter for several reasons, primarily it allows 80% transmission of 850nm and above while blocking the visible light spectrum (400nm to 700nm)
– small Phillips head screw driver
– Two Small blade type screw drivers
– utility knife
– latex/nitrile/cotton gloves (to reduce finger prints)
– ruler or calipers Step One:
The Logitech camera comes with a flexible monitor mount/support arm that is connected to the camera housing with three screws. these screws are hidden on the underside of the mount behind a small rectangular piece of black plastic that has been glued in place. Using the utility knife or one of the blade screw drivers, pry back and remove the plastic cover and remove the screws. The USB cables strain relief is connected to this mount also and needs to be removed in order to completely remove the mount. Using the utility knife or screw driver pry the small rubberized block at the end of the cable away from the mount.
Turn the camera on end so the end cap is visible. Make sure that you are operating on the side of the housing that has the lens in it. this will be the housing side that is removed. Use the two small blade screw drivers to pry the center button out of the end cap. Two screws become visible Once the end cap is removed. Remove those screws and the entire end cap and outer housing will be freed.
Inside you will find an internal structure with a circuit board and lens assembly mounted opposing each other to a metal yolk. Begin by orienting the circuit board so it is visible. Locate and remove the four screws connecting the black plastic lens housing to the metal yolk. Next remove the four screws in the corners of the circuit board. The lens housing should now be free from the yolk and the circuit board should just be connected by its wiring harness. Peel away the black plastic tape from the back of the circuit board to reveal the two screws holding the lens carrier in place. Remove those screws and carefully remove the lens carrier from the circuit board.
Orient the lens carrier so the small square of glass in the base is visible. This is the infrared filter. using the utility knife, carefully score along all four sides of glass to break the glue seal. Slide the tip of the utility knife between the glass and the housing and gently pry the glass out breaking the remaining seal. Take the calipers or ruler and measure the glass. It should measure about 8mm x 8mm. Next, wearing gloves, remove the Kodak filter gel and cut a 8mm x 8mm square. Place the new filter into the lens carrier, gently pressing it into place to ensure that it is seated properly. Keep in mind that this will be in almost direct contact with the camera sensor so it has to be immaculately clean. Any finger print, lint or small piece of dust will show up and distort or ruin your image.
Follow the steps in reverse to reassemble the camera.