Oct 6, 2025
Built the circuit:
I was not familiar with LM358, but I still tried to understant it.
Coding:
I copied the code in the doc but two of the libraries (NewPing, NewTone) cannot being used by Nano. So I asked ChatGPT to change the library to one that works for the Nano. I uploaded successfully and got the number from my ultrasonic sensor in Serial Monitor. But the problem is I couldn’t hear anything from my speaker. I tried to troubleshoot by changing a speaker and adding a transistor to make the sound louder?, but I failed at both :(
What is a theremin?
A theremin is an electronic musical instrument controlled without physical contact by the thereminist (performer). It was patented by Leon Theremin in 1928. The instrument's controlling section usually consists of two metal antennas that sense the relative position of the thereminist's hands and control oscillators for frequency with one hand, and amplitude (volume) with the other.
click to play the video.
it finally worked!!!
credit to Gabriel, and also Justin & Arjun who told me to try this :)