This project is a USB-enabled digital scale! It illustrates the functionality of Hexabitz H26R00 load cell (strain gauge) module. It also uses USB module H1ARx to bridge connection with PC so as to display the weight on computer software and also used to power the modules.
H26R00 module can be used as an industrial scale or home scale with an acceptable accuracy, just choose the right load cell to your application, wire it to the module, and type its values.
A load cell is a type of transducer, specifically a force transducer. They convert a force such as tension, compression, pressure, or torque into an electrical signal that can be measured and standardized. As the force applied to the load cell increases, the electrical signal changes proportionally. The most common types of load cell used is the strain gauge, which we use in our project.
By using a serial terminal like Realterm, a CLI connection could be established with the modules. Set the Baud rate to 921600 then open the port and hit enter to receive the welcoming message. In order to get right measurement we should enter the load cell values provided by the manufacturer calibration sheet to H26R00 module. Just type calibration command where the value needed for this command are 1st the rated full load of the cell in Kg, 2nd the rated output in mV/V, thirdly the zero balance in mV.
Hexabitz USB Scale Software shows the calculated weight acquired by the module H26R00 and selects the preferred unit of measurements, reading value from a load cell connected either to channel 1 or channel 2 of the H26R00 module, rate/time of sent data to be displayed, or one can activate infinite time switch to send measurements endlessly, zero calibration button to remove the possible additional weight produced by the scale dish as an instance and finally STOP buttom to end the receiving. You can find the software's repo in this link: https://github.com/HexabitzPlatform/USB-Scale-Software
When you click read button the software sends a message via virtual serial COM port to H1ARx module, which forwards the message to H26R00 module. H26R00 parses the received message and responds by executing the appropriate APIs, then transmit the calculated weight to USB port in order to be displayed on the GUI of the software.
The messaging packet consists of 8-bytes header, includes information of the source, destination and messaging code, Payloads bytes, could be varies from 0 byte to 52 bytes. Thirdly, the CRC8 byte.
Thanks to the optimized size of Hexabitz modules and 3d printing technology that make producing such enclosure simple and fast. The enclosure is 3D printed of plastic material. Additionally, it is snapfit design and provided with M2 mounting holes on its both sides for mounting on a surface.