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Step 8Lite it up!
When you illuminate the eye with IR light and observe it through an IR sensitive camera with a visible light filter, the iris of the eye turns completely white and the pupil stands out as a high-contrast black dot. This makes tracking the eye much easier. In order to provide some IR illumination, we have made a quick and dirty IR LED circuit using alligator clips, IR LEDs and a 2x AAA battery holder.
The circuit is a simple 3 volt series circuit with two IR LEDs and a power supply (See the napkin circuit drawing below for more details). Connect an alligator clip, preferably a red one, to the power lead from the battery holder. Connect the other end of the alligator clip to the positive leg of one of the IR LEDs. Connect another alligator clip, preferably white or yellow, to the negative leg of the same IR LED and the positive leg of the second IR LED. Finally, connect an alligator clip, preferably black, to the negative leg of the second IR LED. The other end of the black alligator clip should be connected to the negative lead from the battery holder.
You can test to see if the IR LEDs are working by looking at them using most typical point and shoot cameras. If they are sensitive to IR light, you should see a soft glow coming from both LEDs.
Wrap up the excess cable, wire tie the alligator clips to the arm of the glasses and the camera armature. You can use wire ties to attach the alligator clips to the front of the camera. Bend the IR LEDs so they are pointing in the same direction as the camera, bent in toward the eye. Make sure the LED legs are not touching each other or any part of the camera circuit board. You can use electrical tape to help keep all metal components electrically isolated from one another. You will likely have to adjust the IR LEDs once you are looking at the eye in the EyeWriter software in order to get a strong illumination that removes shadows created by the eyelid, lashes and camera frame.
The circuit is a simple 3 volt series circuit with two IR LEDs and a power supply (See the napkin circuit drawing below for more details). Connect an alligator clip, preferably a red one, to the power lead from the battery holder. Connect the other end of the alligator clip to the positive leg of one of the IR LEDs. Connect another alligator clip, preferably white or yellow, to the negative leg of the same IR LED and the positive leg of the second IR LED. Finally, connect an alligator clip, preferably black, to the negative leg of the second IR LED. The other end of the black alligator clip should be connected to the negative lead from the battery holder.
You can test to see if the IR LEDs are working by looking at them using most typical point and shoot cameras. If they are sensitive to IR light, you should see a soft glow coming from both LEDs.
Wrap up the excess cable, wire tie the alligator clips to the arm of the glasses and the camera armature. You can use wire ties to attach the alligator clips to the front of the camera. Bend the IR LEDs so they are pointing in the same direction as the camera, bent in toward the eye. Make sure the LED legs are not touching each other or any part of the camera circuit board. You can use electrical tape to help keep all metal components electrically isolated from one another. You will likely have to adjust the IR LEDs once you are looking at the eye in the EyeWriter software in order to get a strong illumination that removes shadows created by the eyelid, lashes and camera frame.
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Not sure if any one interested, but for a nice compact all in one to include the IR LEDs, will the IR CMOS suck as from Sparkfun electronics here(www.sparkfun.com/commerce/product_info.php) work ? This would be lower cost and a lot less work than modifying the PS3 cam ... ?