[ $7 ] DIY eurorack modular synth LFO&VCO with arduino nano and AD9833 DAC / synthesizer module HD

Aliexpress sell very cheap DAC module and arduino nano. We can make LFO or VCO eurorack module only $7 or less. There is an error in the circuit diagram. In fact, there is a 10kΩ resistor in front of the LED. Code sample and memorandum. https://note.com/solder_state/n/nc287554879d4 My other DIY modular synth movie. $20 DSP effect module: https://youtu.be/7eVQrKnJpI8 $10 EQ module. https://youtu.be/5Pd-gLvyAk0