Table of Contents
- 1 Introduction:
- 2 Components Required:
- 3 Components Description
- 4 Arduino Weighing Machine using Load Cell HX711 Module
- 5 Circuit Diagram: Interfacing HX711 Load Cell with Arduino
- 6 Working Explanation:
- 7 Source Code for Interfacing HX711 Load Cell with Arduino:
- 8 Video Preview & Explanation:
In this project we will be “interfacing HX711 Load cell amplifier with Arduino” and 16*2 LCD for designing Arduino Weighing Machine using Load Cell HX711 Module. This is a simple “Arduino Weight Measurement project”.
Electronic weighing machine uses load cell to measure the weight produced by the load, here most load cells are follows the method of strain gauge, Which converts the pressure (force) into an electrical signal, these load cells have four strain gauges that are hooked up in a Wheatstone bridge formation.
For designing Arduino Weighing Machine using Load Cell & HX711 Module we use the following components. Each and every components are described below further.
1. Arduino UNO Board 2. HX711 Module - (Buy Online from Amazon) 3. Load Cell (Any type like 3 kg, 6 kg, 10 kg, 40 kg) - (Buy Online from Amazon) 4. 16*2 LCD (example JHD162) 5. Tact Switch (Reset Switch) 6. Breadboard 7. Connecting Wires 8. Mounting surface for Load Cell (Nuts, Bolts, Frame, Base) 9. Standard Weight blocks (100 gm)
What is Load Cell?
A load cell is a transducer that is used to create an electrical signal whose magnitude is directly proportional to the force being measured. It is basically a device that measures strain and then converts force into electric energy which serves as measurement for scientists and workers. The strain measurement by load cells helps in maintaining integrity of the unit under pressure and protects people and equipment nearby.
HX711 Load Cell Amplifier
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.
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)
Arduino Weighing Machine using Load Cell HX711 Module
Load Cell & HX711 Connection:
- RED Wire is connected to E+ - BLACK Wire is connected to E- - WHITE Wire is connected to A- - GREEN Wire is connected to A+
Load Cell Assembly on Base:
A base is also required to fix the load cell over it by using nuts and bolts. Here we have used a hard plyboard for the frame for placing things over it and a light wooden board as Base. This is required as load cell bends slightly when some weight is placed over it.
Circuit Diagram: Interfacing HX711 Load Cell with Arduino
Assemble the circuit as shown in the figure for designing “Arduino Weighing Machine using Load Cell HX711 Module” or simply “Interfacing HX711 Load Cell with Arduino“.
Before making the whole circuit to work it is necessary to “calibrate load cell HX711 with Arduino“. For “calibrating Load Cell HX711 with Arduino” we need to put 100g weight at starting when the LCD displays put 100g weight. Once 100gm weight is kept over the load cell, calibration is done. Now simply you can put any weight for measuring with 99.9% accuracy.
Load cell which is an amplifier senses the weight and supplies a electrical analog voltage to HX711 Load Amplifier Module. Then this amplified value is fed to the Arduino where the output of HX711 is converted into the weight values in grams. The output result is displayed on 16*2 LCD.
Source Code for Interfacing HX711 Load Cell with Arduino:
Simply copy this code and upload to the Arduino board. Make sure to have the same connection as indicated above in the circuit diagram of Arduino Weighing Machine using Load Cell HX711 Module.