Hi I've made a dyno to test brushless motors. I'm using a hydro gear motor as the load, with a flow restrict valve to increase/decrease load.
I have the load cell connected to a half metre bar from the gear motor's shaft. So as the load is applied the bar pushes on the cell and gives a kilogram reading. I would like to add an equation to the output (kgs) so instead of giving weight it would be torque. The equation needs to be: scale reading x 9.81 x 0.500/3.75=torque
This is the code I'm using to run the load cell:
/*
Example using the SparkFun HX711 breakout board with a scale
By: Nathan Seidle
SparkFun Electronics
Date: November 19th, 2014
License: This code is public domain but you buy me a beer if you use this and we meet someday (Beerware license).
This example demonstrates basic scale output. See the calibration sketch to get the calibration_factor for your
specific load cell setup.
This example code uses bogde's excellent library:"GitHub - bogde/HX711: An Arduino library to interface the Avia Semiconductor HX711 24-Bit Analog-to-Digital Converter (ADC) for Weight Scales."
bogde's library is released under a GNU GENERAL PUBLIC LICENSE
The HX711 does one thing well: read load cells. The breakout board is compatible with any wheat-stone bridge
based load cell which should allow a user to measure everything from a few grams to tens of tons.
Arduino pin 2 -> HX711 CLK
3 -> DAT
5V -> VCC
GND -> GND
The HX711 board can be powered from 2.7V to 5V so the Arduino 5V power should be fine.
*/
#include "HX711.h"
#define calibration_factor -108650.00 //This value is obtained using the SparkFun_HX711_Calibration sketch
#define LOADCELL_DOUT_PIN 3
#define LOADCELL_SCK_PIN 2
HX711 scale;
void setup() {
Serial.begin(9600);
Serial.println("HX711 scale demo");
scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);
scale.set_scale(calibration_factor); //This value is obtained by using the SparkFun_HX711_Calibration sketch
scale.tare(); //Assuming there is no weight on the scale at start up, reset the scale to 0
Serial.println("Readings:");
}
void loop() {
Serial.print("Reading: ");
Serial.print(scale.get_units(), 1); //scale.get_units() returns a float
Serial.print(" kg"); //You can change this to kg but you'll need to refactor the calibration_factor
Serial.println();
}