I wired my tree with 500 LED lights and calculated their 3D coordinates.

Matt Parker explains how he used a camera and custom code to calculate the 3D coordinates of 500 addressable LEDs on a Christmas tree.

If you support me on Patreon at any point in December 2020 I will film your name on my xmas tree while I give you a thumbs-up of appreciation. patreon.com/standupmaths Huge thanks to Eugénie von Tunzelmann for helping me out with this video. You can see more of Eugénie in my "General Relativity: Top 05 Mishaps [inc INTERSTELLAR]" video. youtube.com/watch?v=Z4oy6mnkyW4 Thanks to Ben Sparks for helping out with the GeoGebra file. You can try an online version here: geogebra.org/m/p2pdz6v2 And of course thanks to Howard Carter for yet one more remix of the Stand-up Maths theme song. The main theme is on bandcamp: standupmaths.bandcamp.com/ If there is enough demand we'll make a Christmas album. Here is my code on github (along with the 3D coordinates of all 500 LEDs on my tree). If you have a program you would like to see run on my tree, email me matt@standupmaths.com github.com/standupmaths/xmastree2020 My prototype LEDs were type WS2801 and wired to as Raspberry Pi Zero. The WS2801 LEDs I used on Amazon. Other retailers are available. amazon.co.uk/dp/B01MDJ3VBC/ref=sr_1_1?_encoding=UTF8&tag=sta… I set-up the Pi to run 'headless' (no monitor or keyboard) largely using this guide: tomshardware.com/uk/reviews/raspberry-pi-headless-setup-how-… I followed this guide to wire and program the WS2801 LEDs. If you use an off-the-shelf power supply you do not need to worry about the mains wiring (which you should not do unless you are qualified). tutorials-raspberrypi.com/how-to-control-a-raspberry-pi-ws28… Then I switched the WS2811 LEDs because I could buy 500 of them (they are also cheaper). I also switched to a Raspberry Pi 3 because my Pi Zero didn't have wifi. The WS2811 LEDs I used on Amazon. Other retailers are available. amazon.co.uk/dp/B0775CC559//ref=sr_1_1?_encoding=UTF8&tag=st… amazon.com/ALITOVE-Individually-Addressable-Advertising-Wate… I wired up the WS2811 LEDs and coded them using this guide. learn.adafruit.com/neopixels-on-raspberry-pi/raspberry-pi-wi… CORRECTIONS: - None yet. Let me know if you spot anything! Thanks again, as always, for Jane Street being my principal sponsor. janestreet.com/ Thanks to my Patreon supporters who funded those LEDs. If this video does well, I'll buy even more next year. patreon.com/standupmaths Filming and editing by Alex Genn-Bash and Matt Parker Music by Howard Carter Design by Simon Wright and Adam Robinson MATT PARKER: Stand-up Mathematician Website: standupmaths.com/ Maths book: wwwh.umble-pi.com Nerdy maths toys: mathsgear.co.uk/