Simple Controller for RGB-LED-Strips

This is a Arduino sketch for a simple LED-Strip Controller. The user-interface is just a normal rotary encoder with pushbutton.

• push or rotate to wake up, then click (second time) to switch on
• rotate to change parameter
• click to switch to next parameter
• double click to switch between effect and global parameters
• long click (hold > 4seconds and release) to switch off

• Global
  • effect
  • brightness
  • overwrite (use only part of led-strip → rest is overwritten with black)
• Effect
  • static
    • hue
    • saturation
  • rainbow
    • duration
    • spread
  • plasma
    • duration
    • spread
    • hue

• Adafruit ItsyBitsy M4 Express
• Pololu Big Pushbutton Power Switch
• SN74HCT125 as levelshifter
• APA102 144Pixel/m *3
• as heatsink for the LED-Strips: Aluminium L-Profile
• MeanWell DC/DC converter SD-100A-5 (in: 12V; out: 5V 18A)

to compile this in arduino you have to install a bunch of additionally libraries: marked with * are my own ones and are not jet added to the library index. (so you have to download and install them the old manual way..)

• slight_DebugMenu *
• slight_ButtonInput *
• slight_RotaryEncoder *
• FastLED
• Adafruit_DotStar

the first concept is written in circuit python. but with a strip of 144*3=432 Pixels this is just to slow ;-) i then ported this to C++. (src_arduino)

the Code is heavily structured with classes. eventually at first this could be complicated to understand..

the main application is split into 3 parts:

• MyMenu a helper class for a serial debug and test menu
• SettingsUI
• MyAnimation
  all things animation related. here the main work happens
  this uses some sub-classes for the effects and parameters.
  This way its easier to automagically handle some of the parameters:
  there are global_current and fx_current and similar variables. these have the base type and so are able to point to child-classes.
  • ParameterBase
  • EffectBase

it is used as interior lighting for a car - therefore a DC/DC converter is used to generate 5V from the 12V extension battery

next time i will reevaluate the DC/DC converter market..
eventually for this it would make more sens to use a Pololu 5V, 15A Step-Down Voltage Regulator D24V150F5 the MeanWell SD-100A-5 is a great thing - but it misses a Enable Input.
so i head to use the external Switch..
the Pololu D24V150F5 has an Enable input - so no need for the extra switch..
also if i had more time in the first design decision phase - and would - why ever -
decide to use the SD-100A-5 i would reconsider just using a Mosfet as HighSide switch -
trying out things like the BTS441TG Smart Power High-Side-Switch

additionally i will try out another chip as levelshifter: SN74LVC2T45
the currently used SN74HCT125 as levelshifter maxes out at about 6MHz Clock/Data speed.
but the LEDs could go up to 20MHz according to some references..
this would give some more space for effect calculations...
(its also fine as is - the classic rainbow gives us 100fps currently...)
the other advantage of the SN74LVC2T45 is its VCC Isolation Feature -
currently i have to disable the outputs of the levelshifter to High-Z manually -
otherwise the leds try to power up from the 5V coming over the data-lines :-(
this isolation feature just does exactly this: if on of the VCC's is off the output is HIGH-Z :-)
one thing less to care about in software ;-)

currently the off-state current consumption is about 4mA@12V
1,5mA are alone for the standby of the small 5V DC/DC converter that powers the uC...
another ~1mA are going to the ItsyBitsy on-Board APA102 led...
so there is a bunch of things that could be improved.
but the Lights are run from the secondary Battery that is charged via solar..