After years of making my nightlights out of Arduino components, I decided to make one using my knowledge of comparators. I started with a schematic from the illustrious Dr. Ruben, but then tweaked the resistance values to be able to adjust the thresholds with a 10k potentiometer, a 10k photocell, and two 10k resistors that I had available.
Nightlight schematic – straight from the Good Doctor Ruben.
Since one of my goals was to use this post as an opportunity to show students a typical progression with circuit building, I built the first circuit on a large breadboard. This allowed plenty of room to make mistakes. Without having to worry too much about placing the wiring, I could free my brain up to think about the fundamentals of comparator circuit building. During this time, I realized that the best way to build the circuit was with a potentiometer to allow the user to select the darkness threshold.
After ensuring the circuit was performing as desired, I wanted to free up my big, expensive breadboard for other projects. Therefore I intended to solder the circuit onto a little protoboard that I had lying around. However while laying out the board, I realized that I wanted to ensure that my connection wires were straight (for aesthetic reasons). Therefore I migrated my large circuit to a mini bread board and now really paid attention to wire placement.
Once I had the wire layout, I was ready to migrate my circuit to a protoboard and solder the connections. Interestingly while soldering my board, I noticed that my wiring was blocking the mounting holes. This required a bit more unsoldering/re-soldering than I was hoping! C’est la vie de l’ingénierie.
And that, as they say is a wrap. For future work, I would like to use Fritzing/Eagle/Altium and to make a surface mount device circuit board. But for now I am on to other things!
Merci Dr. Ruben and Dr. Reamon for the help with Comparators. Bon!