Has anyone else worked with these adc modules from eBay? The chip is supposedly a Texas Instruments ADS1115, but it doesn’t seem to work quite right. I suspect it is grey market – maybe they’re chips that were thrown out by TI because they didn’t pass quality control.
When I read the inputs in singled ended mode, I get the same reading on A0 + A3 and A1 + A2. The readings are correct, based on the voltage I see on some pots I hooked up.
When I read the inputs in differential mode, the result is better. A0_1 reads correct for input A2, with A3 tied to ground. A2_3 reads correct for A0 with A1 tied to ground (weird!?)
I wonder if the silicon that selects which input to read is messed up somehow, and not isolating the inputs properly.
I purchased five of these, and have tried two so far, with the same result.