Light-up Rock Collection Display Case
January 2014
This was a Valentine's Day present for my awesome girlfriend who has lots of rocks. She doesn't collect them per-say, but people keep giving them to her, so now it's kind of a thing.
I used some scrap wood from an old desk and a picture frame for the case. Each rock platform has a little OPB606 IR LED/Phototransistor pair that detects when a rock is covering the sensor and turn on a white LED to illuminate the glorious geologic gems.
I used some scrap wood from an old desk and a picture frame for the case. Each rock platform has a little OPB606 IR LED/Phototransistor pair that detects when a rock is covering the sensor and turn on a white LED to illuminate the glorious geologic gems.
Confusing schematic
This is my very rough scribble of the schematic with the components of each platform. Basically, when the IR LED light is reflected back into the NPN phototransistor, it pulls a line low. This line is fed into an inverter (SN74HC04N) which then outputs a high 5V to the ULN2003. This in turn connects the low side of the white LED to ground (after a current limiting resistor) and turns the light on!
I thought I had more pictures of the construction, but I guess not. Well, here's one of the case coming together:
In action: