Obstacle-Avoiding Robot with a Personality!

Step 4 Assembling The Dropoff Detector

This can be put together on some bare PCB. I just ran over to RadioShack and got one, and snipped the board to fit the circuit. This part is CRUCIAL. If you mess this up, poor Bob may die. The IR detector is a Panasonic PNA4601, but you can get them from RatShack, as well as the resistors and the IR LED. It does not matter what size IR LED you get, juts make sure it's not an IR PHOTOTRANSISTOR. That is a TOTALLY different device. Also, you must use heat shrink tubing or some sort of straw (you can spray-pain it black) to narrow the beam of the IR LED, but it has to be completely sovered (except the end of the LED), or the sensor will NOT work. I used a plastic casing from Parallax. You can order the LED and the casing on their website.

Unfortunately, the frequency range on the IR detector I used was very wide, which means it is much more prone to interference. Luckily, RadioShack offers ones only tuned to 38Khz, which means Bob is less likely to act strange around remote controls and other devices that use IR. The DP2D12's are great because they are virtually interference-free because of advanced optics (the lenses) and circuitry. In future projects, I will not be using regular IR detectors. The Sharp IR's are preferable over simple IR receivers.

NOTE: PIN 8 IS ACTUALLY PIN 10. PIN 9 IS CORRECT