Hi, and thanks in advance for the help.
I'm an electronics noob who's getting a lot of noise in a circuit and would appreciate some help de-noisifying it, please
I had the idea to build a web-enabled bathroom scale as an Arduino project. I ripped apart a cheap digital bathroom scale and gutted the electronics, leaving me with 4 pairs of strain gauges. I have taken 2 pairs of strain gauges and arranged them in a Wheatstone bridge, as per this diagram from http://www.allaboutcircuits.com/vol_1/chpt_9/7.html
Next, I built an instrumentation amplifier as per this circuit from
I used an LM324N quad op-amp with a single-sided supply for this. My R values are 200k?, and my gain resistor is 500?. Both the bridge circuit and the in-amp circuit are driven from the same regulated 5V supply.
I get the amp to do its thing in a useful output voltage range, but the signal never stabilizes to the point where I'd consider the information reliable input to the Arduino's analog input. I'm sure I need some filtering and/or shielding, but not sure how or where to put this.
All advice appreciated!