HX711 Load Cell Module

Product Description

The dual-channel 24 Bit Precision A/D weight Pressure Sensor Load Cell Amplifier and ADC HX711 Module is a small breakout board; for the HX711 IC that allows you to easily read load cells to measure weight. By connecting the module to your microcontroller you will be able to read the changes in the resistance of the load cell; and with some calibration. You’ll be able to get very accurate weight measurements.

This can be handy for creating your own industrial scale, process control, or simple presence detection. The HX711 Weighing Sensor uses a two-wire interface (Clock and Data) for communication. Any microcontroller’s GPIO pins should work and numerous libraries have been written making it easy to read data from the HX711.

Load cells use a four-wire Wheatstone bridge to connect to the HX711. These are commonly colour RED, BLK, WHT, GRN, and YLW.

Each colour corresponds to the conventional colour coding of load cells :

1. Red (Excitation+ or VCC).
2. Black (Excitation- or GND).
3. White (Amplifier+, Signal+, or Output+).
4. Green (A-, S-, or O-).
5. Yellow (Shield).

The YLW pin acts as an optional input that not hook up to the strain gauge; but is utilized to ground and shield against outside EMI (electromagnetic interference). Please keep in mind that some load cells might have variations in colour-coding.

Pinouts :

Analog Side :

1. E+: Excitation positive.
2. E-: Excitation negative.
3. A-: Channel A Negative Input.
4. A+: Channel A positive Input.
5. B-: Channel B Negative Input.
6. B+: Channel B positive Input.

Digital Side :

1. GND: 0V / Ground Power Connection.
2. DT: Data IO Connection.
3. SCK: Serial Clock Input.
4. VCC: Power Input.

Features 

1. Recommended excitation voltage: 5-10V.
2. Two selectable differential input channels.
3. On-chip active low noise PGA with a selectable gain of 32, 64 and 128.
4. On-chip power supply regulator for load-cell and ADC analogue power supply.
5. Selectable 10SPS or 80SPS output data rate.
6. On-chip oscillator requiring no external component with optional external crystal.
7. On-chip power-on-reset.
8. Simple digital control and serial interface: pin-driven controls, no programming needed.
9. Simultaneous 50 and 60Hz supply rejection.