Christmas Lights Improvements last year

 For the past few years I have set up music controlled colourful Xmas lights using Lightshow Pi software (LSPi) running on a Raspberry Pi RPi.  LSPi software hasn't changed in the past three years but it still works and support is still available from enthusiastic users, particularly SoftwareArtist.  I started my updates for Xmas early in December 2021 which helped me produce something useful in time for Xmas day.

Last year I ran the music (MPD) and LSPi on the same server.  My RPi server used for this application had a disastrous SD card failure during the year so I needed to reinstall software on my shiny new RPi4 application server (PI41) this December.  Luckily LSPi configuration was backed up and my notes on installation was up to date.  Currently the MPD music player is active on my web server (PI40) along with the web pages to select and play music.  

LSPi Installation is well documented on reddit.  I followed  the instructions, which have been updated for RPi4.  I encountered one error in building "rpi-audio-levels" which the helpful SoftwareArtist on reddit provided a solution for.  Once I updated RPi firmware, LSPi installation worked fine and I was able to test that LSPi on PI40 was controlling GPIO output properly.

The LSPi configuration required for my setup is quite simple.  Music is streamed in from MPD on PI40 and RGB output provided on three GPIO pins.  The sample LSPi configuration file has detailed explanatory comments for all the options but my cutdown file only requires a few.
The most important command is "stream_command_string" which causes LSPi to listen to the music being played on PI40 by MPD.  Clearly MPD needs to be setup with a streaming output on port 8000 to achieve this in mpd.conf

I found by trial and error the pin_modes, pwm_range and attenuate_pct settings to give a pleasing range of colours on the output.  We need to set preshow_configuration to null to avoid a few seconds delay before the lightshow starts.  I was grateful that this solution avoids the syncing problems I have previously experienced with the lights being a secnd or two behind the music.  The current solution is quite impressive, RPi is calculating Fast Fourier Transforms (FFTs) in real time to determine music frequencies and using these to calculate pwm duty cycles.

The second improvement I made this year was to "finalise" my MOSFET setup.  I use MOSFETs to increase the RPI GPIO voltage to 12V and provide the current that MOSFETs need to drive the 5050 LED strip. Previously a breadboard solution provided this facility.  My track record in transferring working breadboard configurations to perfboard has been abysmal so although the circuit is quite straightforward I was very careful to draw out a design, check it, cut wires to length and find the necessary components before I started.  I colour-coded the RGB wires and on completion made sure the wires were tidy then put labels on the connections.  

I am rather proud of the results, it works a treat and I will probably keep the lights setup all year round.