https://github.com/little-red-rover/lrr-firmware

Firmware for the ESP32-S3-MINI-1 at the heart of Little Red Rover.
https://github.com/little-red-rover/lrr-firmware

esp32 espidf

Last synced: 6 months ago
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Firmware for the ESP32-S3-MINI-1 at the heart of Little Red Rover.

• Host: GitHub
• URL: https://github.com/little-red-rover/lrr-firmware
• Owner: little-red-rover
• License: lgpl-2.1
• Created: 2024-08-25T20:33:42.000Z (9 months ago)
• Default Branch: main
• Last Pushed: 2024-11-18T16:53:44.000Z (7 months ago)
• Last Synced: 2024-11-18T18:03:18.427Z (7 months ago)
• Topics: esp32, espidf
• Language: C
• Homepage: https://www.little-red-rover.com
• Size: 11 MB
• Stars: 1
• Watchers: 0
• Forks: 0
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Little Red Rover Firmware

Firmware for the ESP32-S3-MINI-1 built into the rover's body.

This project uses the Espressif IoT Development Framework (espIDF) [read more](https://github.com/espressif/esp-idf).

## Birds Eye View

Little Red Rover's firmware is responsible for three tasks:

1. Establishing Wi-Fi connectivity

2. Reading information from sensors (LiDAR, IMU, wheel encoders)

3. Writing commands to actuators (wheel motors)

4. Relaying sensor data and recieving commands over a TCP connection

Because all high level algorithms are run on the base station computer (see [lrr_ros](https://github.com/little-red-rover/lrr-ros)), the rover itself has very little control logic.

Instead, it's optimized for network transmisison and reception.

## API

The rover hosts a TCP server listening on port 8001.

When connected to the rover's hotspot, the ESP32-S3 has the IP address `192.168.4.1`, making the TCP server address `192.168.4.1:8001`.

Send commands using the format defined in the protobuf schema [messages.proto](https://github.com/little-red-rover/lrr-firmware/blob/16-refactor-as-c%2B%2B/components/communication_stack/socket_manager/messages.proto).

To recieve data, the client must first send a SubscribeRequest message with the relevant OutgoingMessageID.

The rover will then begin sending data to that port.

TODO: update link on C++ PR merge.

## Composite Technologies

### FreeRTOS

The system is based on FreeRTOS, a realtime embedded operating system (RTOS).

FreeRTOS provides scheduling and mutlithreading utilities that are crucial for running efficiently in an asynchronous networking environment.

### NanoPB

In order for data to be transmitted over the network, it needs to be serialized appropriately.

This project uses [Google's ProtocolBuffers](https://protobuf.dev/).

Specifically, the firmware uses an embedded focused implementation of ProtocolBuffers called [NanoPB](https://jpa.kapsi.fi/nanopb/).

## Project Structure

* `/main`

  * `lrr_main.cc`: The firmware entry point. Initializes drivers.

* `/components`

  * `/communication_stack`

      * `/wifi_manager`:

         * Initializes wifi

         * Handles provisioning (connecting to Wi-Fi using remotely provided credentials)

         * Connects to Wi-Fi

         * Sets up NAPT so that users can connect to the internet through the rover

      * `/socket_manager`:

          * Multithreaded TCP server implementation

          * Manages multiple client connections, data subscriptions, and general network IO

  * `/hardware_drivers`

      * `/battery`:

          * Measures battery using the ADC

          * Telemeters battery level data

      * `/drive_base`:

          * Integrates encoder pulses using the ESP32-S3 pulse counter module (PCNT) 

          * Drives PID control for the motors

          * Accepts joint state commands as JointCmd messages (see protobuf message definition)

          * Telemeters joint state information as JointState messages

      * `/imu`:

          * Reads data from the IMU over I2C

          * Telemeters IMU data as IMU messages

      * `/lidar`:

          * Reads data from the LD20 LiDAR over UART

          * Telemeters LiDAR data as LaserScan messages

      * `/status_led`:

          * Provides a function to set the status LEDs in response to system events

## Development Environment

The `/docker` and `/.devcontainer` folder provide a devcontainer environment for development.

The docker container uses privilaged mode to flash the ESP32-S3 over USB. The privilaged flag is not supported on MacOS or Windows, so this may not work for you.

Cross platform build instructions are a WIP.