Hello I am a software engineer and I dont have much experience of analog electronics.
I am doing a project of weight measurement using HX711 weighing sensor .
below shown is a rough schematic of my circuit .
I am trying to measure various weights . As i increase the load cell capacity the fulctuations seems to increase as well .
For load cells of 1 ton and more the fluctions increase tremendously . I have interfaced Hx711 with raspberry pi using this library Tatobari-hx711.
i tried averaging that is given in this library ,that too doesnt seem to work.
I also read that the Excitation vtg to load cell thru HX711 is noisy so i am powering the loadcell from SMPS itself .
Questions
1) Is there a simple way to reduce fluctions ? What can I try ?
2)what can be done in software to reduce noise ?
3)if the output of load cells is same (0-20mv) why does this issue arise ? is it due to multiplication factor ? lower range load cells work fine ..is it due to stable first bits of ADC output ?
4)I read somewhere that fluctions can be reduced using some hardware peripherals like resistors .
how to do it ?
Best Answer
I experimented this fairly extensively as a mOhm meter set-up here: https://dannyelectronics.wordpress.com/2015/10/25/a-hx711-based-milliohm-meter/
you can try filtering, either in hardware or software. or using a different adc.
filtering.
not sure what you meant by "this issue". noise is inevitable, especially for high resolution adc. sometimes that noise can be a very useful feature in some applications.
in some applications, yes. cannot see how resistors alone can help here.