HX711 features dual-channel 24 Bit Precision A/D Weight Pressure Sensor Load Cell Amplifier which is available in a small breakout board. The board has pinouts for the microcontroller and the Load cell in two different directions for the ease of interfacing. It can be interfaced with any microcontroller using Data and Clock pins.
This module supports input voltage from 2.7V to 5V, making it ideal for the 3.3V and 5V microcontroller operations. A Resistive Load cell with two differential inputs can be used with this module and could achieve high accuracy in low and high weight measurements.
This low cost, analog front load cell amplifier is the perfect choice for Balance and load cell interfacing. The current consumption of this amplifier is also low with less than 1uA in power down state and 1.5mA only in normal operation or active state.
The load Cell Amplifier is a small breakout board for the HX711 IC that allows you to easily read load cells to measure weight. By connecting the amplifier 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 hookup guide below 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.
- Excitation voltage: 5-10V.
- Current consumption: <1uA (Powerdown state), 1.5mA (Normal Operation state)
- Differential input channels: 2
- On-chip active low noise PGA gain: 32 / 64 / 128 (can be selected)
- Has On-chip power supply regulator for load-cell and ADC analogue power supply.
- Output Data rate support: 10SPS / 80SPS (can be selected)
- Has an oscillator onboard eliminating external components.
- Has optional external oscillator
- Simple digital control and serial interface: pin-driven controls, no programming needed for ease of usage.
- Simultaneous 50 and 60Hz supply rejection for better accuracy.
- Small size of 16×24 mm.
– Weighing scale
– Industrial measurement
– Load Balancer
Ways to use it:
– Use one sensor with an external resistor to form a full-bridge measurement, the range of a sensor range 50kg, external resistance on the higher requirements.
– Use two sensors to form a full-bridge measurement, measuring range for the sum of the two sensors, 2 x 50kg = 100kg
– Use four sensors to form a full-bridge measurement, measuring range for the sum of four sensors, 4 x 50kg = 200kg
Full Example with Arduino, click here
1 x HX711 Amplifier Module