Vixen Christmas Light Controller — Arduino Mega Daisy Chain

Overview

Vixen Lights is free PC software for sequencing Christmas light displays to music. It sends channel data over serial to a controller, which maps the channels to output pins driving relay boards or SSRs.

This sketch turns an Arduino Mega 2560 into a Vixen controller with support for daisy-chaining multiple boards — so a large display can use more channels than a single Arduino provides.

How It Works

Vixen sends a packet of channel bytes terminated by an 'E' footer character over serial. The Arduino reads 43 bytes, maps them to GPIO pins 3–53 (skipping serial port pins), and drives them HIGH or LOW.

// First board reads from USB serial; chained boards read from Serial2
#define FIRST_IN_CHAIN

#ifdef FIRST_IN_CHAIN
  #define INPUT_SERIAL Serial
#else
  #define INPUT_SERIAL Serial2
#endif

After consuming its 43 channels, the board forwards the remaining bytes downstream via Serial3 to the next Arduino in the chain. Each board in the chain consumes its slice and passes the rest along.

Channels Per Board

• Pins 3–53 = 51 potential output pins per Mega
• Serial port pins (0, 1, 14, 15, 16, 17) are excluded from output to avoid conflicts
• Multiple boards chained = 51 × N total channels

Hardware Setup

• Arduino Mega 2560 (one per ~50 channels)
• Relay board or solid-state relay (SSR) array connected to output pins
• Serial3 TX on board N → Serial2 RX on board N+1
• USB from PC to first board only

Vixen Configuration

In Vixen, configure a Generic Serial controller pointed at the COM port of the first Arduino at 115200 baud. Sequence channels 1–43 (or however many you’re using) to the controller output.