I have a project that require me to measure pressure (300N force on 1 20x20mm area). so i decided to try the load cell from sparkfun and the hx711. my schematic is as follow for a single cell.
download/file.php?mode=view&id=6563
the support is telling me to use the following schematic which i totally don’t understand.
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Red and green wires need to go to RED and BLK.
Black and white wires need to go to GRN and WHT
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Any reason why you chose a 3 wire sensor and not the 4 wire sensor the HX711 is looking for? Probably be easier to just use a 4 wire sensor.
Measure the resistance of your sensor and figure out what wire is the center tap. That wire and the center tap of your other two resistors are the excitation wires and the remaining two wires are your outputs.
Those three wire load cells are really crummy. I have some experience in the biz and have only seen them in the lowest quality bathroom scales (and for hobbyists, makers, other secondary markets like SFE).
I am having the same issue with my setup reading zero no matter how I change the calibration number. Everything is the same with my setup as above except I am using a 5 kg Strain Gauge that has 4 wires. I followed all the steps online and can’t figure out why it will only read 0 lbs. Please if anyone has any tips. I know the HX711 is working properly because red and black is measured to be 5 V green and white outputs gets something between 0 and 4 V.
Did you mean between 0 and four millivolts? A typical full bridge strain gauge load cell should have an output in millivolts, seldom higher than about 50 mV at rated capacity and very unlikely to be higher than 20 for your 5 volt excitation.joewill1411:
Please if anyone has any tips. I know the HX711 is working properly because red and black is measured to be 5 V green and white outputs gets something between 0 and 4 V.
