You wired the op-amp as a Comparator…not as a Voltage follower!
The diagram in the data sheet is a SIMPLIFIED diagram. Look up op-amp circuits (comparators and followers) then use LT Spice.
My thoughts exactly. While a simple pot won't have the same output impedance that the real device would have, that's a don't care in this case. Other than that, he's dialing up a voltage w/a pot.dlotton:
I think you’re making this way too hard. Is it really necessary to try to replicate the bridge circuit? Aren’t you just trying to get a variable voltage into your ADC input to test some code?
I modeled the resistor + pot circuit in LT Spice, then breadboarded it and found near perfect agreement between calculated and measured with the pot providing between 0.178V to 4.32V (I used 220 ohm resistors instead of 274 ohm).
For the WS Bridge + OP AMP circuit, I changed it from a Comparator to a Follower and now find that the pot provides a nice linear change between 0.124V to 3.19V.
For testing my Arduino + BLE sensor board I’ll use the simpler resistor + pot circuit.
The reason for going down the OP AMP path was to gain the experience.
I appreciate everyone’s help and patience as I come up to speed on this stuff.
Thanks,
Bob
Ok, dead ends is part of the learning. You now have another tool, LT Spice, to help you on your way.
have fun