Gpredict GS-232 Satellite Rotator Controller

This repository contains two complementary components for a DIY satellite tracking rotator system:

• Arduino-based firmware for controlling a pan/tilt head using the GS-232 protocol.
• A Python-based proxy server that listens for rotor commands from applications like Gpredict and forwards them to the microcontroller using the GS-232 protocol on a serial connection.

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📁 Directory Overview

gs232rotator/

• Platform: ESP32-S3 (Arduino)
• Implements a subset of the GS-232 rotor control protocol
• Controls relays for azimuth and elevation motion
• I am using a BNO055 IMU sensor for compass bearing (AZ) and tilt (EL)

gpredictpythonrotatorproxy/

• Lightweight Python 3 socket server
• Listens on TCP port 7777
• Emulates a subset of the rotctld (Hamlib) commands
• Communicates with the ESP32-S3 controller via serial to control the motors via GS-232

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⚙️ Setup Instructions

1. Flash the firmware in gs232rotator/ to your ESP32-S3 using Arduino IDE.

2. Run the Python proxy on your computer:

   or edit the .bat file and run it from there

   python rotator_proxy.py --serial-port COM12 --baud 115200 --listen-host 127.0.0.1 --listen-port 7777

3. Configure Gpredict:

   • Name RS232Proxy
   • Host: 127.0.0.1
   • Port:7777
   • Az Type: 0 > 180 > 360

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🧭 Sensor Calibration

The BNO055 sensor must be calibrated to ensure accurate azimuth (AZ) and elevation (EL) readings.

On first boot, if no calibration offsets are found in EEPROM, the system will automatically enter calibration mode and display calibration progress on the OLED screen. Once calibration is complete, offsets are saved to EEPROM.

You can manually re-run calibration anytime by sending the CALIBRATE command over serial.

🛠 Calibration Procedure

1. Power on the system. If no offsets are stored, it will enter calibration mode automatically.
2. Rotate the system gently in all directions (pan and tilt) until all four systems reach 3/3/3/3:
   • SYS (System)
   • GYR (Gyroscope)
   • ACC (Accelerometer)
   • MAG (Magnetometer)
3. When calibration is complete, you'll see CALIBRATION DONE! on the display.
4. The offsets are written to EEPROM and used automatically on future boots.
5. You can view the current offsets using the CALSTATS serial command.
6. If desired, copy the printed offsets and hard-code them by enabling USE_HARDCODED = true in your firmware and updating the defaultOffsets struct.

🔤 Related Serial Commands

Command	Description
CALIBRATE	Starts the calibration routine
CALSTATS	Prints current calibration offsets

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🧾 Serial Command Reference

The ESP32 controller accepts a mix of GS-232-style and custom serial commands over USB (or virtual serial via proxy).

🎛 GS-232 Compatible Commands

Command	Description
AZxxx.x	Set target azimuth (e.g. AZ123.4)
ELxxx.x	Set target elevation (e.g. EL45.6)
AZ	Report current azimuth
EL	Report current elevation
P	Report current position as AZ EL
SA	Stop azimuth movement
SE	Stop elevation movement
VE	Report firmware version (returns VEAdamESP32v1.0)
Q or q	Disconnect from Gpredict / rotctld

🛠 Custom Utility Commands

Command	Description
HELP	Show list of available commands
CALIBRATE	Start calibration and store offsets to EEPROM
CALSTATS	Print current calibration offsets

All responses end with a \r (carriage return), as expected by Gpredict/rotctld.

Invalid or unknown commands will return RPRT -1\r.

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🔌 Hardware Used

• Panasonic WV-7230 pan/tilt head (relay-controlled)
• 4-channel relay module
• ESP32-S3 or similar microcontroller
• ESP Breakout Board
• SSD1306 0.96 I2C OLED Board
• BNO055 (IMU with absolute orientation for compass bearing)
• 24v AC/AC adapter
• Project Box
• 24VAC 5VDC Step down converter
• Mounting Kit

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📝 License

This project is licensed under the MIT License.

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🤝🏼 Maintainer

Created by Adam Melancon