4 layers32 × 60 mm OctoHX711, the printed circuit board in 3D

OctoHX711

Eight HX711 modules on one board

Size: 32 × 60 mm
Copper layers: 4
Thickness: 1.6 mm
Parts: 105
Nets: 109
Pads: 352
Tracks, vias: 614, 35
Pours: 1
Routed: Yes
KiCad: KiCad 7 (file 20221018)
Created: 7 May 2023
Updated: 6 Jul 2023

Overview

OctoHX711 is an open-source printed circuit board by Aightech, from the Aightech/OctoLoads repository on GitHub, published under the GPL-3.0 licence. It is a 4-layer board of 32 × 60 mm with 105 parts on 109 nets, routed with 614 tracks and 35 vias.

It is built around the HX711 and MMBT4403LT1G. Its parts include 35 capacitors, 32 resistors, 12 connectors, 8 ICs and 8 transistors.

Main components

README

README.md

OctoLoads: 8-Channel Load Cell Measurement PCB

OctoLoads is an 8-channel load cell measurement Printed Circuit Board (PCB) designed for projects that require simultaneous readings from multiple load cells. With 8 HX711 modules on a single board, it offers a practical and efficient solution for managing and synchronizing measurements across several load cells.

Visualisation

Top	Bottom

Features

text

8 HX711 modules for measuring up to 8 load cells simultaneously
Shared clock bus for perfectly synchronized measurements
Selectable sampling rate: 10Hz or 80Hz
Compatible with various load cells
Optimized PCB layout for signal integrity, power distribution, and thermal management

Applications

text

Industrial weighing systems
Multi-axis force/torque measurements
Robotics and automation
Agricultural and food processing equipment
Fitness and sports equipment

Getting Started

text

Hardware Setup: Connect your load cells to the octoLoads board following the appropriate wiring diagram provided in the documentation.

Sampling Rate Selection: Choose between the two available sampling rates (10Hz or 80Hz) by setting the jumper on the board as described in the documentation.

Microcontroller Integration: Connect the octoLoads board to your microcontroller or processing unit, and utilize the provided library or API for seamless integration.

Software Setup: Import the provided octoLoads library into your project, and follow the example code in the documentation to start taking measurements from your load cells.

Documentation

Detailed documentation, including schematics, layout files, and instructions for use, is available in the docs folder.

Support

For any questions or issues, please raise an issue'

License

This project is licensed under the MIT License - see the LICENSE file for details.

Code

Building source code

To build the project run:

bash

cd octoLoads
mkdir build && cd build
cmake .. && make

Demonstration app

When the project have been built, you can run:

bash

./octoLoads -h

to get the demonstration app usage.

Example

Open the [Image blocked: main.cpp] file to get an example how to use the lib.

Parts

105

Qty	Value	Footprint	References
26	100nF	Capacitor_SMD:C_0402_1005Metric	C1, C11, C12, C13, C15, C16, C17, C19, C20, C21, C23, C24, C25, C27, C28, C29 +10
16	100	Resistor_SMD:R_0402_1005Metric	R3, R4, R7, R8, R11, R12, R15, R16, R19, R20, R23, R24, R27, R28, R31, R32
9	10uF	Capacitor_SMD:C_0402_1005Metric	C2, C6, C10, C14, C18, C22, C26, C30, C35
8	20k	Resistor_SMD:R_0402_1005Metric	R1, R5, R9, R13, R17, R21, R25, R29
8	3.3uH	Inductor_SMD:L_0603_1608Metric	L1, L2, L3, L4, L5, L6, L7, L8
8	8.2k	Resistor_SMD:R_0402_1005Metric	R2, R6, R10, R14, R18, R22, R26, R30
8	Conn_01x04_Male	Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Vertical	J1, J2, J3, J4, J5, J6, J7, J8
8	HX711	Package_SO:SOP-16_3.9x9.9mm_P1.27mm	U1, U2, U3, U4, U5, U6, U7, U8
8	MMBT4403LT1G	digikey-footprints:SOT-23-3	Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8
2	Conn_01x03_Male	Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical	J10, J12
1	Conn_01x02_Male	Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical	J11
1	Conn_01x08_Male	Connector_PinHeader_2.54mm:PinHeader_1x08_P2.54mm_Vertical	J9
1	LOGO	LOGO	G***
1	SolderJumper_2_Bridged	Jumper:SolderJumper-2_P1.3mm_Bridged_RoundedPad1.0x1.5mm	JP1

Questions

How big is the OctoHX711 PCB?

It measures 32 × 60 mm and has 4 copper layers, 1.6 mm thick.

What parts does the OctoHX711 use?

105 parts, built around the HX711 and MMBT4403LT1G. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Where can I download the OctoHX711 KiCad files?

From the Aightech/OctoLoads repository on GitHub, at the commit this page was made from: the board is models/octoHX711/octoHX711.kicad_pcb and its schematic models/octoHX711/HX711_unit.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the OctoHX711 design in my own project?

Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).

Project files

Show this board on your page

A live frame, for any web page

<iframe src="https://pcbkit.io/embed/boards/aightech-octoloads" title="OctoHX711 in PCBKit" width="100%" height="480" style="border:0;border-radius:12px" allow="fullscreen" loading="lazy"></iframe>

A picture

<img src="https://pcbkit.io/embed/boards/aightech-octoloads.jpg" alt="OctoHX711" width="1200" height="900">

A picture that opens the board, for a README

[![OctoHX711](https://pcbkit.io/embed/boards/aightech-octoloads.jpg?size=s)](https://pcbkit.io/boards/aightech-octoloads)

Source

Repository: Aightech/OctoLoads
Board file: models/octoHX711/octoHX711.kicad_pcb
Commit: 9fef32d
Licence: GPL-3.0

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