Mini DMX Patcher
The purpose of this PCB is to offload the complexity of running logic or patterns for a specific fixture from the control desk to the firmware itself. It inserts into an existing DMX universe with standard DMX XLR5 in and through connectors, with a third output that goes directly to the fixture to control.
The main reason for building this board was to enable control of the 25 dimmable lamps in the Blinder Wall lighting piece without needing to manually program patterns and behavior into the main lighting desk for the whole DMX universe(s). Because this piece is designed to be used in multiple locations that all have different and unknown lighting control, I needed to make a simple and uniform interface for interacting with the wall.
The Mini DMX Patcher mounted in the main Blinder Wall enclosure with the incandescent dimmers
The hardware is very basic:
- XLR5 input/output pair for input and passthrough of the DMX universe
- Separate XLR5 output for custom DMX output to fixture
- USB-C connector for 5V power and programming
- DIP switch to set the DMX address
- Power and status LED indication
The majority of the functionality of this device is implemented in the firmware. It handles receiving incoming DMX packets and parsing the channel footprint from the correct address, then outputting the expected effect with the correct speed and with any overrides that might be applied. For example, the twenty-five-channel Blinder Wall can be controlled with only five channels of input to the Mini DMX Patcher:
- Master dimmer - controls overall max brightness cap of the lamps
- Effect - fifteen different effects available
- Effect rate - the overall speed that the effect executes at
- Effect blocker - a boolean flag allowing the controller to change effect and speed settings without them propagating to the fixture until the user is ready
- Blinder override - controls the floor value of every lamp, allowing the controller to manually raise the overall brightness of every lamp
Due to its simplicity, this PCB can be reused for any fixture to alter the behavior of its built-in channel group with only some changes to the firmware.