On a free side Venom VB-303 sounds good, but is painful to use
PinkDuck
maybe something like littlebits kit? I haven't tried them myself, but they look fun, educational and kids friendly (not sure about 3yo thou)
https://www.youtube.com/watch?v=E7B0mWvnE1Q
No, with 0 Ohm I get a perfect 0+5v sine, just as I need. It's the other way round, it'll amplify the signal and clip off the top at about + supply voltage when you increase the resistance in the feedback loop, but it's not exactly square wave, as the bottom part of sine will remain intact. I use clipping schottky diodes to protect the arduino from voltage outside 0+5v range, this way if you increase input signal to say 20v peak to peak, you'll get more square-ish wave in 0+5v (I've attached the schematics)
it worked! (at least in the sim)
thanks a lot!
I'm not sure I got all the math right, since I get 0 - 5.05V on the output, but it's not a deal breaker for me.
I attached the schematics, but not sure that images in comments federate from kbin to lemmy, so if you don't see it, try opening an original link to this comment.
I already ordered PCB for the prototype. I hope it'll work fine. Thanks a lot for your help :)