- Sun Sep 03, 2017 12:57 pm
#196023
I'm connecting 4 strain gauges (stripped out of a bathroom scale) to the Combinator -> HX711 -> Arduino, pretty much like the Sparkfun example online but I'm not getting any valid readings. (I built a previous prototype and it did work). I am using the "bogde" library and using a scope I can see the HX711 communications look good. (The first data bit is a 1 and the following 23 data bits are 0's).
I measured the strain gauges to determine the center tap and connected the to "C" on the Combinator. For the other connections I went by the recommended color code.
On the Combinator board the excitation voltage is ~3.3V, the voltage on the white is ~1V, and the voltage on the green is about 2V.
Questions:
1) Could my issue be as simple as the remaining two wires (for each of the 4 strain gauges) need to be reversed? (I know I have the center tap correct).
2) Even though all 4 strain gauges came out of the scale and are coded the same, could the two wires from each gauge (not the center tap) not be consistent? (I.e. could one or more of the strain gauges be connected incorrectly?)
3) Knowing the change in resistance is beyond the capability of my multimeter, is there a simple way to determine which wire from the strain gauge is the variable and which one is fixed?
Any thoughts/comments/suggestions appreciated!
I measured the strain gauges to determine the center tap and connected the to "C" on the Combinator. For the other connections I went by the recommended color code.
On the Combinator board the excitation voltage is ~3.3V, the voltage on the white is ~1V, and the voltage on the green is about 2V.
Questions:
1) Could my issue be as simple as the remaining two wires (for each of the 4 strain gauges) need to be reversed? (I know I have the center tap correct).
2) Even though all 4 strain gauges came out of the scale and are coded the same, could the two wires from each gauge (not the center tap) not be consistent? (I.e. could one or more of the strain gauges be connected incorrectly?)
3) Knowing the change in resistance is beyond the capability of my multimeter, is there a simple way to determine which wire from the strain gauge is the variable and which one is fixed?
Any thoughts/comments/suggestions appreciated!