Every B.Tech student at my college is required to take a basic electronics class in the first year. Keeping this class in mind, some faculty members asked me to design an orientation activity for the incoming batch of 400 students that would introduce people to electronics.
Inspired by the slew of really cool badges from DEFCON (https://www.defcon.org/html/links/dc-badge.html) and Anool (https://hackaday.com/2015/08/17/developed-on-hackaday-lets-build-some-more-hardware/) I decided to build a badge that doubled as a learn to solder kit for the incoming students.
I wanted to make the circuit completely analog so that students could see it as an extension of the basic electronics class they take, that they can see an actual application of the transistor, capacitor and diode circuits they will go on to learn to build in the semester. This also had the added advantage of being very cheap.
Admittedly, the fact that the circuit had to be as cheap as possible means it isn’t terribly interesting – it’s a bunch of photoresistors that control the brightness of leds. cover the photoresistor with your finger and leds should become brighter. That said, this was my first foray into getting more than 1-2 boards fabbed, and turned out to be quite an interesting learning experience in that regard.
Also many thanks to Anool, who not only gave me some tips on improving my board layout but created his own version of the layout, which spells out my college’s name on the board. You can find schematics, parts list and both versions of the layout on my Github (https://github.com/CalmDownKarm/BML-Badges)
Just a note, the 1$ price tag is at scale – my college needed to make something like 300 of these. If you only do <100 and use OSHPark or PrestoPCB, the unit cost will be much higher.