Automated Material Tensile Testing Machine

A custom-built tensile testing machine that clamps a specimen, pulls it apart using a linear actuator, and logs force and displacement data to a CSV file on a USB drive

How It Works

The system uses a dual-microcontroller architecture:

Raspberry Pi 5 ("Brain") — runs the Python controller (Pi_Software/controller.py): handles the e-ink display, GPIO buttons, state machine, USB data logging, and serial communication with the Arduino.
Arduino Mega 2560 ("Control Center") — runs the firmware (Arduino_Firmware/): reads the load cell (HX711) and position sensor (ADS1115), drives the motor (DROK L298), and streams 100Hz telemetry over USB serial to the Pi.

The Pi sends M,<speed> commands; the Arduino replies with DATA,<force_lbs>,<position_raw> at 10ms intervals.

Repository Structure

├── Arduino_Firmware/
│   └── Arduino_Firmware.ino              # Arduino Mega firmware
├── Pi_Software/
│   ├── controller.py                     # Main Raspberry Pi controller
│   └── epdconfig.py                      # E-ink display configuration
├── Documentation/
│   ├── Automated Material Testing.md     # Full technical reference
│   ├── SETUP.md                          # Pi OS setup & systemd service
│   ├── USER_GUIDE.md                     # Operating the machine
│   ├── wiring_diagram.svg                # Full wiring diagram
│   └── Images/                           # Build photos
│   └── BOM.xlsx                          # Bill of Materials (components and model details)

Getting Started

If you're setting up the machine from scratch, follow these docs:

BOM.xlsx — All hardware used
Wiring Diagram
Technical Reference — full architecture, pinouts, and calibration
SETUP.md — configure the Raspberry Pi OS, install dependencies, and set up the systemd service
USER_GUIDE.md — operating manual

Hardware

Component	Manufacturer	Model
Raspberry Pi 5 (4 or 8 GB)	Raspberry Pi	SC1112
Active Cooler for Raspberry Pi 5	Argon	AR-THRML-30MM
Arduino Mega 2560 Rev3	Arduino	A000067
Screw Terminal Breakout	Electronics-Salon	Mega Screw Shield
Load Cell ADC	Various	HX711
Position ADC	Various	ADS1115
DC Motor Driver	DROK	L298
e-Paper Display	Waveshare	2.7" HAT V2 (13512)
Power Expansion Board	Yahboom	Power Expansion Board

Load cell, string potentiometer, and linear actuator are not listed — these are application-specific and may vary.

See SETUP.md for setup instructions.

COA/Sod_Strength_Testing

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