Nandhopper 1-Bit Noise Synth

Step 6 Plug it In and Finalize

Plug it in! Grab a 9 V battery (if you haven't already been using one), some headphones, and test it out. It should be outputting a 0-9 V signal, while sound normally runs at +/-1V. But sound systems also tend to have capacitors in line with the input that center things around 0 V and remove any DC bias. You should still be careful with volume: start with it off, and slowly turn it up.

As you improvise you might discover a lot of strange things: touching sensors together might cause weird sounds; depending on how you've wired it, touching the sensors without applying force might even cause some strange sounds.

If nothing works, check for broken connections or things in contact that aren't supposed to be in contact. Debugging these is probably more work than it's worth, and if it's not obvious you might be better off building a new one.

If everything works correctly, leave things plugged in and start hot gluing everything in place. Start with the audio connector, and then soldering "real" (shorter) connections between the chip and audio jack. Then hot glue everything that looks like it could ever come undone. This synth isn't meant to last for a long time, but the glue will help when you inevitably drop it. I leave things plugged in just to make sure I'm not breaking anything as I apply the glue.