Thanks to online shops like AliExpress, DX, Banggood, Wish and countless others you can buy all sorts of random, interesting and sometimes useless shit for very cheap.
Usually I buy from AliExpress and most of the time its some electronic stuff that are way overpriced in my country, or I just can’t get them locally. In this case, I was browsing through as usual and was recommended these seemingly random ICs (integrated circuits) that to me (as a kid that liked to tear things apart and see what’s inside) looked a bit familiar from electronic toys or interactive souvenirs.
So I looked through most of them and got hit by nostalgia and interest to see how they function and what can they do. I ordered a few different types of ICs and most of them are sold in bulk.
All of the modules that I found are bare and you need to add extra components yourself, which mostly are a some kind of an NPN transistor and a 104 ceramic capacitor. Also there are no schematic or any information whatsoever about them, so you either poke the contacts yourself to see how these work or search the obscure code written on the PCB and hope for the best.
In my case, I searched, and if you dig deep enough you can find the relevant information.