About Lumière

This code is a firmware for a smart light system called Lumière (meaning «Light» in french). The underlaying design goals are to provide a relative agnosticism from the physical implementation.

Given the overkill computing power given by modern µ-controllers and the respective order of magnitude of electrical consumption between the «power stage» and the «command stage» of the system, we can neglect low-level (and non-interoperable) optimisation strategy.

This code rely on c++11 capabilities to provide compilation-time checking and computation, especially througt template metaprogramming and generalised constant expressions.

For the sake of simplicity and pedagogical purpose, we’r using arduino framework instead of the naked AVR lib, if limitation began to arise, we’ll feel free to switch.

But, arduino IDE is a real shit for anyone loving to code and the lake of integrated CLI compile-chain make it necessary for us to use the CLI part of platformIO (and emacs as an OS).

once this intalled compiling and flashing the fireware should be as easy as :

platformio run -t upload

Copying constraint

Please keep in mind that while it is legal to seel system based on the fireware, your only obligations are those of the GPLV3: give the same right to your customers your where given here.

Physical implementation

The actual physical system which is running this code consist of :

• An arduino mega compatible-board (a chinese copy, in this case).
• A power-stage constitued of a 12v led-strip power-source (probably recycled by the maker from a laptop power) and SMC MOSFET (AMP3055L TO-252 N Channel MOSFET) dimentioned (paralellized or not) accordignly to every chanel it had to drive.
• led strips :
  • Warm light
  • Red
  • Green
  • Blue
  • Grow (optimized spectrum with no green and low blue)

I don’t have any global schematic for the system as its simplicity allow it to be built from the top of (y)our head; if you think otherwise, ask for it and I’ll try to draw one.

Practical goals

Lumière is built on an simple electronical structure with modularity in mind.

As many libre software, this system is designed at first to cover one of the author need, which is this case :

• Live in a underground studio with only a 50/25cm window for 27m² divided in two room.
• Want to keep a circadian-cycle compatible with social life and matching with the sun (ie: daylight are shorter in winter and the overall spectrum is shift by atmopheric scatering (and quantic effect) due to declinaison).
• Want the system to be independant from computer, network connection and able to work on batteries (and aware of the power-source switching).
• Want to handle multiple light channel, with independant semantic (ie: grow-light for plants can’t be driven exactly like warm-white light for human).
• The overall cost should be minimal but we limited hacking and recycling to physical interface (switch, galvanometers & co.), the electronical part will be composed from standard (ie: with lot of equivalent ) part easely found on the actual and future market.
• Control interface should be electro-mecanical (physical switchs…), it’s vintage, can last years and be recycled easily. To allow the system to be hackable, the interface component should be easy to plug into the code.

in the hope that it will be useful.

Librement,

Yann Asset