From 950cca331159b643ac6453aeadfbb64eccfa7661 Mon Sep 17 00:00:00 2001 From: Paul Oliver Date: Thu, 17 Jul 2025 03:04:52 +0200 Subject: Initial --- README.md | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 README.md (limited to 'README.md') diff --git a/README.md b/README.md new file mode 100644 index 0000000..e63aae5 --- /dev/null +++ b/README.md @@ -0,0 +1,26 @@ +# HsMouse Quad A4988 Motor Controller HAT + +> **Warning**: This project is not intended for production use. +> It is a learning exercise for KiCad and PCB design fundamentals. + +![quad-a4988-rev2-render01.png](quad-a4988-rev2-render01.png) +![quad-a4988-rev2-render02.png](quad-a4988-rev2-render02.png) + +## Overview + +This Raspberry Pi 5 HAT features four A4988 stepper motor driver chips, +designed to control four NEMA stepper motors. The primary application is a small robotic car using +[Mecanum wheels](https://eu.robotshop.com/products/60mm-mecanum-wheel-set-2x-left-2x-right) +for omnidirectional movement. + +## Features +- **Motor Control**: Four A4988SETT-R drivers for independent control of NEMA stepper motors. + - Shared GPIO connections for common pins (e.g., `MSx`, `ROSC`, `~ENABLE`) + to simplify control logic. + - Assumes synchronized wheel speeds when enabled. +- **Precision Voltage Reference**: ISL21080 provides a stable 0.9V reference + to all A4988 `VREF` pins, limiting motor coil current to **1.125A**. +- **Directional Logic**: SN74LVC2G08DCUR dual AND gate enables diagonal wheel movement + by selectively disabling `STEP` signals (see movement table below). + +![wheel-rotations.png](wheel-rotations.png) -- cgit v1.2.1