StepperController

Final Limit Switches Version

This version uses hardware limit switches for position sensing and safety. All code and documentation reflect the last release before switching to optical sensors.

Overview

StepperController is an ESP32-based stepper motor controller for MagLoop antenna positioning, featuring ESP-NOW wireless communication with a touchscreen GUI.

Hardware Requirements

• ESP32 DevKit V1
• DM542 Stepper Motor Driver
• NEMA 23 Stepper Motor
• Limit Switches (for position sensing)
• 24V DC Power Supply

Pin Connections

ESP32 Pin	Connection	Description
GPIO 18	DIR	Direction signal to DM542
GPIO 19	STEP	Step pulse to DM542
GPIO 22	DOWN_LIMIT	Down limit switch (INPUT_PULLUP)
GPIO 23	UP_LIMIT	Up limit switch (INPUT_PULLUP)

Communication Protocol

ESP-NOW wireless protocol with StepperGUI touchscreen controller.

Message Format

typedef struct __attribute__((packed)) {
    uint8_t messageId;
    CommandType command;
    int32_t param;
} Message;

Supported Commands

• Movement: CMD_UP_SLOW, CMD_UP_MEDIUM, CMD_UP_FAST, CMD_DOWN_SLOW, CMD_DOWN_MEDIUM, CMD_DOWN_FAST
• Positioning: CMD_MOVE_TO
• Control: CMD_STOP, CMD_RESET
• Status: CMD_GET_POSITION, CMD_DOWN_LIMIT_STATUS

Features

• Non-blocking operation
• Real-time position feedback to GUI
• Hardware limit switch integration
• Multiple speed settings
• Message queuing for ESP-NOW

Build and Upload

platformio run
platformio run -e esp32doit-devkit-v1 --target upload --upload-port COM3
platformio device monitor --baud 115200

Project layout

.  (limit switches version)
├── src/
│  └─ main.cpp
├─ MagLoop_Common_Files/   # Git submodule with shared headers
├─ lib/
├─ platformio.ini
├─ download_latest_all.bat
└─ upload_changes_all.bat

Configuration

Pulse delays and limits are declared in src/main.cpp. The runtime PD values are persisted using the ESP32 Preferences API under the stepper namespace.

Update the GUI MAC address in src/main.cpp if needed:

const uint8_t GUI_MAC[] = { 0x98, 0xA3, 0x16, 0xE3, 0xFD, 0x4C };

Updating shared files

Run the included batch scripts to synchronize shared files and GUI code:

download_latest_all.bat
upload_changes_all.bat

State machine

States include STATE_IDLE, STATE_MOVING_UP, STATE_MOVING_DOWN, STATE_MOVING_TO, STATE_MOVE_TO_DOWN_LIMIT, and STATE_RESETTING.

Troubleshooting

• ESP-NOW issues: verify MAC addresses and peer configuration
• Motor not moving: check wiring, DM542 enable/config and power
• Limit switches: confirm INPUT_PULLUP wiring and logic

Contributing

1. Fork
2. Create branch
3. Make changes
4. Update MagLoop_Common_Files if shared definitions change
5. Test controller + GUI
6. Submit PR

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See also: StepperGUI (GUI project) and MagLoop_Common_Files (shared headers)