This circuit enables you to toggle a digital signal on and off every time an on-board infrared slot sensor is breached. It employs a JK flip-flop circuit that is configured for toggle-mode, a power-on-reset (POR) circuit to ensure that the output is always low on power up, and an H21A1 infrared slot sensor. The video below includes a schematic review of the circuit, two demonstrations, and assembly instructions for a kit that I've developed.
Here is the eagle schematic: http://www.electroniclessons.com/slot.pdf
The library for the H21A1 isn't all that great, but I was in a hurry when I made that specific library.
Here is what you'll need to do it yourself:
1x 470 Ohm resistor
1x 10k Ohm resistor
1x 100k Ohm resistor
2x 10uf capacitors (electrolytic)
1x 0.1uf capacitor (ceramic)
1x PCB or breadboard
1x H21A1 IR slot sensor
1x 74LS109A PGT (Positive Edge Triggered) JK Flip-Flop IC. You can use NGT as well (Negative Edge Triggered)
1x 16-pin IC socket (Optional)
You can hook it up to a little security system interface, or to your arduino, or to a relay/driver board to control AC devices. It's very easy to put together, and is relatively inexpensive to make. It can also be easily modified. Anyhow, I hope you enjoyed this video. I had fun making it. Please don't hesitate to let me know if you have any questions at all =)
Happy new year, everyone!