Based on Avia Semiconductor’s patented technology, HX711 is a precision 24-bit analog-to-digital converter (ADC) designed for weigh scales and industrial control applications to interface directly with a bridge sensor.
UNIVERSAL-SOLDER HX711 break-out board allows you to easily read load cells to measure weight. By connecting this AD converter 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 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. Check the HX711 PDF Data Sheet (google for it) for more information.
Load cells use a four-wire Wheatstone bridge configuration to connect to the HX711. These are commonly colored RED, BLK, WHT, GRN and YLW. Each color corresponds to the conventional color coding of load cells:
– Red (Excitation+ or VCC) – Black (Excitation- or GND) – White (Amplifier+, Signal+ or Output+) – Green (A-, S- or O-) – Yellow (Shield)
The YLW pin acts as an optional input that is not hooked 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 slight variations in color coding.
HX711 Specifications: • Two selectable differential input channels • On-chip active low noise PGA with selectable gain of 32, 64 and 128 • On-chip power supply regulator for load-cell and ADC analog power supply • On-chip oscillator requiring no external component with optional external crystal • On-chip power-on-reset • Simple digital control and serial interface: pin-driven controls, no programming needed • Selectable 10SPS or 80SPS output data rate • Simultaneous 50 and 60Hz supply rejection • Current consumption including on-chip analog power supply regulator: normal operation < 1.5mA, power down < 1uA • Operation supply voltage range: 2.6 ~ 5.5V • Operation temperature range: -40 ~ +85?