Hi, Im having some trouble with spark fun load cell amp
its got it wired as a wheatstone using 3 strain gauges and one pot (set to 350ohms as nominal value of the strain gauges are)
I can get some data and it reacts when i touch the gauge. however it wanders around like mad
Ive attached a screen cap of the serial plotter.
If anyone has any ideas i would love to hear them,
Many thanks in advance
No wiring diagram, no code posted, I think you're on your own with that problem as we definitely don't have enough information to be able to help you.
I have seen 1/4 bridge (single strain gauge), I have seen half bridge (two strain gauges) and I have seen full bridge (four strain gauges) but I have never seen three strain gauges and a pot configured as a strain gauge bridge so a schematic would be nice and label the stressed and non-stressed gauges. You make no mention of the gauges used? You make no mention of the excitation voltage applied or the excitation source?
Build your bridge, apply a highly stable excitation voltage. Build the bridge as a 1/4 or 1/2 bridge configuration. If you want to include a potentiometer for a zero balance then have at it. Balance your bridge and less any applied force (stress) you have real close to zero volts out. Measure with a good quality meter which I assume you have. Apply some small stress to the gauge configured for stress be it tension or compression. What does the meter do?
You start at the beginning and only once you know what you have and that it works you move along to amplifying your load cell output with a HX711. You can use the HX711 for an excitation source if needed. I suggest you start with an off rhe shelf load cell rather than try to roll your own unless you have a good understanding of strain gauges and their applications.
Provide a schematic and code as was mentioned, it will make things go much easier.
Ron
