kojigardiner / ambilight-client

Ambient back-lighting for TV

Ambilight-Client

Ambilight is a content-aware LED installation that provides back-illumination for a TV.

This repository contains source for the ESP32-based client device. A separate Ambilight server device sends data to the client and consists of a Raspberry Pi with a camera pointed at the TV. The server and client communicate via UDP.

Definitions

Server = Raspberry Pi with camera (ambilight-server)

Client = ESP32 device (ambilight-client or audiobox)

Protocols

Messages are defined and serialized using nanopb and compiled for C (ambilight-client) and Python (ambilight-server). Definitions are stored in a separate repository.

UDP Network

Discovery

1. Server starts a timer and sends a broadcast message continuously until timeout.
2. Clients that hear the broadcast start a timer and continuously respond until timeout with the following:
   • IP address
   • Port
   • Type (audiobox, ambilight-client)
   • Number of LEDs
   • LED format (serpentine grid, rectangular perimeter, ...)
3. Server stores each client's info in a dict and continuously sends ACKs until the timeout.
4. Clients that receive an ACK stop responding
5. Server/clients stop after timeout.

Sending Data

1. Server sends data
   • Sequence #
   • Server timestamp
   • LED RGB array
     • for ambilight, this will be TV data
     • for audiobox, this will be images, animations, etc
2. (Optional) Clients ACK every received transaction
   • ACK
   • Sequence #
   • Client timestamp

Control Schemes

1. Web server on Raspberry Pi (ambilight-server)
   • Admin server used to adjust camera position and debug client connections.
2. Web server on ESP32 (ambilight-client)
   • Similar to the audiobox controller, this will allow simple on/off controls and mode changes (e.g. TV mode vs solid color modes).

State Machines

Client

State: START

• Behavior: Setup UDP port to receive broadcast messages.
• Transition: Once setup, transition to IDLE.

State: IDLE

• Behavior: Listen for discovery message.
• Transition: On receipt of discovery message, store server's IP/port, start timer for DISCOVERY_MS, and transition to DISCOVERY state.

State: DISCOVERY

• Behavior: Send config packets every DISCOVERY_CONFIG_MS.
• Transition: On receipt of ACK, transition to DATA state. If no ACK is received before timeout, transition to IDLE state.

State: DATA

• Behavior: Listen for data messages and parse. If the sequence number is larger than the last received, immediately send to LEDs and update the last seen sequence number.
• Transition: On receipt of discovery message, transition back to IDLE state in order to re-establish connection.

Server

State: DISCOVERY

• Behavior: Start DISCOVERY_MS timer. Send discovery packets every DISCOVERY_BROADCAST_MS. Listen for config packets, and when received, add client's information to dictionary and send ACK.
• Transition: On timeout, transition to DATA state.

State: DATA

• Behavior: If data is available, send it to all clients in the dictionary.
• Transition: None

Animations