Webcam Capture in Twittering Laser Tripwire

The project illustrates how a laser trip wire is made to twitter and capture an image from a webcam while executing any bash script command.

A GNU/Linux or Mac operating system is required for this kind of system which can support a fully functional Processing IDE and Arduino IDE. A more complex processing application can be created if the project is implemented in Windows. For the hardware part, the project would require an Arduino board, a light dependent resistor, another 100KOhm resistor, and a laser pen or pointer.

During the construction, the laser and LDR should be in a position where they would not move around. To prevent ambient light from affecting the reading the LDR was slipped into the end of a ballpoint pen. A small amount of hot glue on each edge of Arduino board was used to secure it to a plastic cassette case.

The leaser should be ensured to be pointed at the LDR. The screen area should be green and should turn red when the laser is blocked. It would turn back to green after 10 seconds. The 10 seconds hold ensures not twittering the same message.

Rest of the project