bogde
Weight slowly decrease after the calibration
Hi, I'm facing a problem with my stuffs. I did the calibration following the guide and everything worked fine, but after the first reading the weight starts to decrease slowly and I don't know why. I did the tare with a 15.4 Kg weight, so I divided the average of 10 readings by 15.4 and after the calibration the first reading is exactly 15.4 kg (so it's correct) but after this one the readings start to decrease reaching around 12.5 Kg (so a difference of less 2.9 Kg). What should the problem be in your opinion? I was thinking that I'm using a poor quality load cells but why the first reading should be correct?
P.S. I have 4 load cells connected following the attached scheme. There's also a screenshot of the serial monitor.
I found an interesting thing: if I change the unit from kilograms to grams, so if I divide the readings by 15400 g, the readings will be more accurate and there won't be that huge decreasing; there would be a maximum of aroung 500 g difference between the readings (see the screenshot)
I try to power the wemos d1 with external power supply instead usb, but the result is the same. Connecting vcc to 5v o 3.3 don't change the result
Ok, but i I cannot explain why interpreting the signal in grams the creep is less
UPDATE: i'm using now a 10 kg load cell but i have instability values `#include "HX711.h"
// HX711.DOUT - pin #d4 // HX711.PD_SCK - pin #d3
HX711 scale(D4, D3); // parameter "gain" is ommited; the default value 128 is used by the library
void setup() { Serial.begin(115200); Serial.println("HX711 Demo");
scale.set_scale(); // this value is obtained by calibrating the scale with known weights; see the README for details scale.tare(); // reset the scale to 0 Serial.print("PIAZZA IL PESO"); delay(5000);
Serial.print("il fattore di calibrazione è:\t"); float fattore= scale.get_units(10)/1000; Serial.print(fattore); scale.set_scale(fattore);
Serial.println("Readings:"); }
void loop() { Serial.print("one reading:\t"); Serial.print(scale.get_units(), 1); Serial.print("\t| average:\t"); Serial.println(scale.get_units(10), 1);
scale.power_down(); // put the ADC in sleep mode delay(5000); scale.power_up(); }`
Ba⸮11 Demo PIAZZA IL PESOil fattore di calibrazione è: 204.32Readings: one reading: 1000.2 | average: 999.7 one reading: 995.5 | average: 998.4 one reading: 994.5 | average: 998.2 one reading: 994.9 | average: 997.7 one reading: 993.5 | average: 997.8 one reading: 995.3 | average: 998.5 one reading: 995.4 | average: 998.3 one reading: 993.7 | average: 997.6 one reading: 994.7 | average: 997.4 one reading: 993.1 | average: 997.6 one reading: 993.8 | average: 996.8 one reading: 995.1 | average: 997.2 one reading: 992.8 | average: 997.9 one reading: 993.3 | average: 997.0 one reading: 994.0 | average: 996.8 one reading: 991.6 | average: 996.8 one reading: 992.3 | average: 996.1 one reading: 992.5 | average: 995.8 one reading: 992.1 | average: 996.2 one reading: 993.3 | average: 997.1 one reading: 991.5 | average: 996.6 one reading: 1001.9 | average: 1004.3 one reading: 1003.0 | average: 1006.5 one reading: 999.2 | average: 1003.0 one reading: 996.5 | average: 1000.2 one reading: 992.1 | average: 997.1 one reading: 994.2 | average: 997.6 one reading: 1005.6 | average: 1007.9 one reading: 994.2 | average: 999.7 one reading: 991.4 | average: 999.8 one reading: 991.2 | average: 996.0 one reading: 994.4 | average: 996.2 one reading: 994.5 | average: 997.6 one reading: 994.5 | average: 997.0 one reading: 994.7 | average: 997.9 one reading: 1005.5 | average: 997.6 one reading: 993.6 | average: 996.4 one reading: 997.2 | average: 998.9 one reading: 992.7 | average: 995.9 one reading: 991.9 | average: 996.1 one reading: 993.9 | average: 997.0 one reading: 994.9 | average: 997.9 one reading: 993.7 | average: 997.3 one reading: 998.9 | average: 1001.4 one reading: 994.3 | average: 997.2 one reading: 994.8 | average: 996.1 one reading: 994.7 | average: 998.4 one reading: 996.8 | average: 1004.8 one reading: 1000.2 | average: 1001.6
The connections are solid and the wire soldered on the hx711
i'm stuck in this project, i try to use a raspberry, arduino but the readings are not stable..