# K2Aley GAR-BOT Remote Control Transmitter

Copyright (c) 2026 K2Aley. GAR-BOT. All rights reserved.

The GAR-BOT remote control transmitter now uses the Raspberry Pi Zero 2 W with
the Pico Voice board shown in the reference photo.

![RP Zero 2 W + Pico Voice transmitter reference](reference_photos/RPzero2w-PicoVoice_remote_transmitter.jpg)

## Controller Change

Removed from transmitter design:

- Arduino Pro Mini
- Old Arduino Pro Mini/nRF24L01+ joystick transmitter PCB as the active control
  brain

Added to transmitter design:

- Raspberry Pi Zero 2 W
- Pico Voice board / voice HAT
- LoRa transmitter path
- Optional touchscreen/USB setup from the Pi Zero 2 W if needed

## Transmitter Role

The transmitter sends safe command packets to the GAR-BOT Raspberry Pi 5 robot:

- drive forward/reverse
- turn left/right
- stop / emergency stop command
- open left claw
- open right claw
- open both claws
- close left claw
- close right claw
- close both claws
- request robot status

## Board Connections

| Transmitter part | Connects to | Notes |
| --- | --- | --- |
| Raspberry Pi Zero 2 W 40-pin header | Pico Voice board header | Main voice/control stack. |
| Pico Voice `I2C` connector | Optional I2C buttons/display | Use only if needed. |
| Pico Voice `GP12` connector | Optional command button/input | From photo label. |
| Pico Voice `SPEAKER` connector | Small speaker | Voice feedback. |
| Pico Voice `HEADSET` connector | Headset/audio | Optional. |
| Pi Zero 2 W USB | LoRa USB bridge or serial adapter | Use for DX-LR30/SX1262 transmitter if not on GPIO. |
| Pi Zero 2 W GPIO SPI | LoRa module SPI | Optional direct SPI path. |
| Pi Zero 2 W power | 5V battery bank or protected 5V regulator | Do not power from weak USB source during radio TX. |

## LoRa Transmitter Signals

If wiring LoRa directly to Pi Zero 2 W SPI:

| LoRa signal | Pi Zero 2 W GPIO |
| --- | --- |
| SCK | GPIO11 / SPI0 SCLK |
| MISO | GPIO9 / SPI0 MISO |
| MOSI | GPIO10 / SPI0 MOSI |
| NSS / CS | GPIO8 / CE0 |
| DIO1 | GPIO25 |
| BUSY | GPIO24 |
| RESET | GPIO23 |
| 3.3V | Pi 3.3V only |
| GND | Pi GND |

Use a proper LoRa antenna before transmit.

## Software

Use `remote_control/remote_agent.py` as the transmitter-side starter script.
It sends JSON command packets over UDP by default so it can be tested over Wi-Fi
before the LoRa serial link is finalized.

## Enclosure Notes

Print or build a handheld case for:

- Raspberry Pi Zero 2 W
- Pico Voice board
- speaker/headset opening
- command buttons
- battery bank
- LoRa antenna bulkhead
- K2Aley GAR-BOT label

Keep the antenna outside the case and keep metal away from the antenna path.

## Old PCB Photo

If using the older green Arduino Pro Mini/nRF joystick PCB as a physical
reference, treat it as layout inspiration only. The Pro Mini is removed from the
active transmitter design and should not be wired as the main controller.