/kait-hx711

Primary LanguagePythonApache License 2.0Apache-2.0

Dual HX711 Server for RasPi, accessible by JSONP

Hardware connection

Connect two HX711 boards to RasPi GPIO pins. The connected pin numbers should be written in ble.sh & webserv.py

BOARD_1_CK, BOARD_1_DT = 5,6
BOARD_2_CK, BOARD_2_DT = 27,22

Install / Run (BLE version)

  1. install necessary libs
sudo pip3 install pybleno
  1. run
$ sudo ./ble.sh
  1. Access

https://sowd.github.io/kait-hx711/

  1. Autorun
$ sudo crontab -e

then add the following line.

@reboot /home/pi/kait-hx711/ble.sh

Install / Run (HTTP version)

  1. install necessary libs
$ python3 setup.py install
  1. run
$ ./webserv.sh
  1. Access

Default port is 8080. If you want to modify, supply -P option.

curl http://hostname:8080

JSONP

curl "http://hostname:8080?callback=abcdefg"
  1. Autorun
$ crontab -e

then add the following line.

@reboot /home/pi/kait-hx711/webserv.sh

Calibrate

calibrate-estimate.js eEstimates raw value -> gram mapping by Gram = a * RawValue + b using least square fitting

References

The original README of Tatobari's hx711py repo follows.

HX711 for Raspbery Py

Quick code credited to underdoeg's Gist HX711.py. I've only made a few modifications on the way the captured bits are processed and to support Two's Complement, which it didn't.

Update: 25/02/2021

For the past years I haven't been able to maintain this library because I had too much workload. Now I'm back and I've been working on a few fixes and modifications to simplify this library, and I might be commiting the branch by mid-March. I will also publish it to PIP.

Instructions

Check example.py to see how it works.

Installation

  1. Clone or download and unpack this repository
  2. In the repository directory, run
python setup.py install

Using a 2-channel HX711 module

Channel A has selectable gain of 128 or 64. Using set_gain(128) or set_gain(64) selects channel A with the specified gain.

Using set_gain(32) selects channel B at the fixed gain of 32. The tare_B(), get_value_B() and get_weight_B() functions do this for you.

This info was obtained from an HX711 datasheet located at https://cdn.sparkfun.com/datasheets/Sensors/ForceFlex/hx711_english.pdf