Designing a DMX controlled Patio Light with Neopixels

A friend of mine has approached me to make him some Patio lights. He wants them to be interactive! I'm thinking the best idea would be to make him some sort of DMX controlled light with WS2815 LEDS. I can build on the previous design work I have already done which should save me some time. 

For the enclosure my plan is to take an existing garden rock lamp and re-engineer it for this purpose. This should save me having to design some clever aesthetics. To that end I have bought a cheap (£3.20) garden lamp from B & Q - A popular Home / garden improvement chain in the UK: 

https://www.diy.com/departments/grey-solar-powered-integrated-led-outdoor-lamp/5059340020471_BQ.prd

The lamp itself looks like this:

   

Simple Garden Solar charging rock lamp

The lamp housing appears to made of some sort of ABS moulded plastic.  The Reflector and LEDS are protected by a simple circular polycarbonate shield.  There is a battery housing and a button on the base of the housing.

Don't turn it on - Take it apart!!!

The deconstructed lamp

The light actually came apart very easily...it was mainly hot glued together!  The reflector, battery box and solar panel will be discarded as they won't have any purpose in the upcycled lamp.  I will probably leave the solar panel on as getting it off will be difficult and it won't do any harm.

There is ample space inside the lamp for a couple of circuit boards and some ballast (weight) to stop the lamp moving too easily.  My current thinking is to design two circuit boards.  One for the DMX and one for the lighting.  The controller will be a small microcontroller board which accepts DMX and outputs SPI to the lighting board.  The lighting board will be a circular PCB with WS2815 LEDS arranged in a sensible pattern.  If I'm luck it will be possible to fit 32 LED pixels on the display board.

I have not decided which microcontroller to use yet...probably an arduino or teensy variant.  There is no need to go for a wifi enabled micro as the plan is to use wire to carry both power and the DMX signal.

The diameter of the reflector is 84 mm.  I think the lamp PCB will need to be the same dimensions.  Hopefully we can get 32 W2815 LEDS (Pixels) to fit!

So to recap our electronic and mechanical requirements:

Design a lamp PCB with 32 pixels.  I think powering the lights via 12 volts might be a good idea however I will consider this more once I get to the PCB layout.  We will need to ensure the tracks are suitably rated for the current flow.  We will fuse the voltage signal on the control board with a user changeable fuse.

Nice to haves: 32 pixels - allows for simple channel assignment via DMX controllers.  Each lamp on one universe...with 96 channels.  

So the design tasks so far:

• Design a Lamp PCB
• Design a DMX to neopixel PCB with optocoupled DMX in and out ports - possibly using the one I've already designed.  
• The micro is yet to be decided.
• The circuit will also be powered via 12 V dc but we will probably need to regulate that down to 5 V dc for the micro and other circuitry...sound detection, light detection etc.

I haven't got a budget set however cheaper is always better!

That will do for now!  Take care - Langster!