I have a small update on this. I ended up using my laptop for the first test, not a Raspi. I got an MCP4725 eval board from Microchip and a Bus Pirate for I2Cing with it via USB and a terminal emulator. I could resolve 1-bit voltage steps in the DAC Vout using just a basic (but decent) multimeter. The 5V and ground were from the laptop USB, so at 12 bit (0-5V) the ~1 mV steps were easy to resolve. There was some drift, but the voltages stayed within "their" bits. So MCP4725 performs as expected. Now need to make the 5V reference and the amp for the piezo.
Statistics: Posted by runcyclexcski — Wed Jan 28, 2026 9:17 pm