Hello all,
I've designed a circuit to measure an EMG signal (attached file). The circuit, by itself, works like I'd expect; however, for the end design, I need to connect it to an ADC (I'm using ADS1015, controlled by a PIC18F4520 microcontroller); the Vref and the Vout go directly to the A1 and A0 pins, respectively, of the ADS1015. The voltages measured are correct, but, whenever I connect the circuit to the microcontroller/ADC circuit, I see a voltage between the Vin + and - pins (~0.25 V) and between each of the input pins and the reference pin (~1.8 V). When I run the circuit alone, these voltages don't show up. I tried putting in an optoisolator between the two circuits, but it didn't get rid of these voltages. Does anyone have an idea how to fix this? Thanks so much!