AD623 AD620 Instrumentation Amplifier Module - 1 Channel, 1000 Microvolts, 6V Max Supply, Part Number LYAD6203

I'm getting ready to drain and refill my pool, and I want to measure how much water it takes to fill it. So I bought a Hall effect flow sensor , but its output is millivolts. I needed a large enough voltage swing to reliably generate an interrupt to my Arduino Uno. There are other ways to have done this, obviously, but this works well. I replaced the fixed gain resistor with the supplied pot and adjusted its output before feeding that to my debounce IC. The pot might not be stable enough for your precise requirements, but it's just fine in my application here.

My experience with these has been a little painful because when I first bought them it seems there was no documentation, and I burned two of them up experimenting. Then on the third one, I saw the documentation and I got it right and got 100x amplification.Here's what I've learned:1) Don't connect V- to ground or any other known voltage. It doesn't mean negative supply voltage. It's an output for driving other devices. Leave it disconnected for a simple amplification application.2) Connect Vref to ground for normal amplification3) The documentation isn't clear about the gain resistor setup! The board is already wired with a gain resistor R3 of 10K, so if you add nothing the gain is 101, not 1. To get a gain <101 you have to unsolder R3 (it's easy) and solder in the thee holes a larger potentiometer or fixed resistor. Note that of the 3 pot soldering holes, the two right ones come connected, so it only matters what resistance is between the left hole and the other two. The documentation says "R3 and potentiometer can only be welded one". I think they mean to use only R3 or the pot, but from their diagram, R3 and the pot are in parallel, so you should be able to use them both if you know how resistors add in parallel and you want gain >101.4) Be careful with it. I think a burned up one having my voltmeter set on ohms instead of volts when testing the output

I think I will start a petition to get Amazon to establish a ZERO star review.I seem to be having to send a lot of stuff back to Amazon lately. I removed the R3 resistor and tested it at G=1 and it seemed to work OK. I then installed the pot and set it for a gain of 10. Using a five millivolt DC input, it works for about four minutes and then goes berserk – the output rapidly increasing. Shut it off and wait a minute or so and it works again for a while. The input is stable. Not driving a big output load. The power supply is five volts from a stable source. The board is not hot but it seems like an over-temperature problem. Cooling the board did not help.The documentation is terrible. A lot of chinglish gibberish. There is no actual circuit diagram that I can find. The circuit board has no mount holes so if you can get it to work you have to figure out some way of mounting it.

first: read the amazondrive documents.then these tips might help fine tune: remember to tie REF to common if it isn't used; v- is an output of negative voltage generated by the board; remove fixed gain resistor if you want to use the pot.I measured the voltages and compared to what the mfr has, and they agreed within measurement uncertainty.i know others had troubles, but it worked perfect and was quite robust in dealing with some issues i had on breadboard. The problem i made was that if i forgot to supply an input as described in the documents from mfr, the voltage out could float upwards.my circuit card were silk screened very nicely. overall, a great little help for me amplifying signals under 100mV.