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Check with a multimeter that red-yellow is one coil and blue-orange is the other. The chart shows that you've got to start the stepper at about 500 Hz and ramp up. Starting at too high a frequency will cause it to stall. 500 Hz would correspond to 2 ms per step rather than 0.5 ms which is what your delay = 0.0005 is giving you.


I would approach this a bit differently from the previous answers, given the inaccessible internal voltage reference and the optionally differential input(s) of the ADS1115 (and the nice 2's complement bipolar measurement of differential signals). simulate this circuit – Schematic created using CircuitLab The TL431 is used to bias the inputs well ...


If you want a simple solution that doesn't require opamps or other active circuits, you can offset the -5 - +5 signal with your 5V supply: Connect your input via 10 kΩ to the ADC's input. Connect that node also to +5 V with another 10 k Ω. Now the ADC will see signals from 0 to +5 V which represent: ADC = (5V+VIN)/2 If you don't have +5 V, use +3.3, and ...


If the RPi and AC do not share a ground, you can AC couple and DC bias to mid supply: simulate this circuit – Schematic created using CircuitLab But no isolation, and I assume this is mains, and I assume you got +/-5V from the mains through a stepdown transformer. If not and you used a divider, get rid of it and use a transformer. Not safe. If you ...

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