Matthew Cragun
A simple loadcell calibration program based on a load cell and HX711 amp. Using HX711 by Bertrand Bouvier. Calibration code comes from SparkFun example at https://learn.sparkfun.com/tutorials/load-cell-amplifier-hx711-breakout-hookup-guide?_ga=1.169212841.987765858.1442369657.
Revision 0:5f789b9ae213, committed 2015-11-28
- Comitter:
- mcragun
- Date:
- Sat Nov 28 19:35:24 2015 +0000
- Commit message:
- A sample loadcell calibration program.
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/HX711.lib Sat Nov 28 19:35:24 2015 +0000 @@ -0,0 +1,1 @@ +http://developer.mbed.org/users/laskowsk/code/HX711/#716e1cbdac61
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Sat Nov 28 19:35:24 2015 +0000
@@ -0,0 +1,49 @@
+#include "mbed.h"
+#include "HX711.h"
+
+DigitalOut gpo(D0);
+DigitalOut led(LED_BLUE);
+HX711 scale(A0, A1);
+
+AnalogIn scaleRaw(A3);
+Serial pc(USBTX, USBRX); // USB Serial Terminal
+float calibration_factor = 1000; //-7050 worked for my 440lb max scale setup
+int averageSamples = 100;
+
+int main(void)
+{
+ pc.printf("Starting Scale");
+ pc.printf("HX711 calibration sketch");
+ pc.printf("Remove all weight from scale");
+ pc.printf("After readings begin, place known weight on scale");
+ pc.printf("Press + or a to increase calibration factor");
+ pc.printf("Press - or z to decrease calibration factor");
+
+
+ scale.setScale(0);
+ scale.tare(); //Reset the scale to 0
+
+ long zero_factor = scale.averageValue(averageSamples); //Get a baseline reading
+ pc.printf("Zero factor: %.4f\n" , zero_factor); //This can be used to remove the need to tare the scale. Useful in permanent scale projects.
+
+ while (true) {
+ scale.setScale(calibration_factor); //Adjust to this calibration factor
+ float weight = scale.getGram();
+ //float raw = scaleRaw.read();
+ pc.printf("Reading: %.2f\n", weight);
+ //pc.printf("Raw Value: %.7f\n", raw);
+ pc.printf(" calibration_factor: %.2f\n", calibration_factor);
+
+
+ if(pc.readable()) {
+ char temp = pc.getc();
+ if(temp == '+' || temp == 'a')
+ calibration_factor += 10;
+ else if(temp == '-' || temp == 'z')
+ calibration_factor -= 10;
+ }
+ gpo = !gpo; // toggle pin
+ led = !led; // toggle led
+ wait(0.2f);
+ }
+}
\ No newline at end of file
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Sat Nov 28 19:35:24 2015 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/165afa46840b \ No newline at end of file