Episode: 3123
Title: HPR3123: Arduino controlled Christmas lights
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr3123/hpr3123.mp3
Transcribed: 2025-10-24 17:16:40

---

This is Hacker Public Radio Episode 3123 for Wednesday, 22 July 2020. Today's show is entitled
Arduino Control Christmas Lights
and is part of the series Arduino and Related Devices. It is the 10th anniversary show of Archer 72
and is about three minutes long and carries a clean flag. The summary is
controlling Christmas LED lights within Arduino.
This episode of HPR is brought to you by AnanasThost.com. Get 15% discount on all
shared hosting with the offer code HPR15. That's HPR15. Better web hosting that's
unfair at AnanasThost.com.
Hello, this is Archer 72. Welcome to Hacker Public Radio.
I had the idea to take three strings of LED lights that were on my Christmas tree
and make them reactive to the music. I started with the project with an Arduino Uno
as basically a breadboard to make sure the project would work first.
I tried initially powering it the project with USB power but it made the audio signal unstable
and I was having outputs to the LEDs even though I didn't have an input from music or anything.
So I tried plugging it into the power at the barra plug and that seemed to work out a little better.
After I finished the project, I ended up using a generic Arduino Nano to control the project
and slated the other one to use for another time.
I took a preamp that was off Amazon and I modified it to...
I took the electric mic off and took the inputs and used that to take the laptop,
music source and input it to the preamp.
I ran the output from this preampifier to A0 on an analog input to the Arduino
and then split the signal out to an external speaker so I could still hear what the music was going on.
I used the digital outputs listed in the sketch, the three outputs to power the LED indicators
and as for a reference if you're not familiar, the sketch is a program that the Arduino runs through a loop.
I used pins 10 to 12 as an analog right to provide power which is a range of 0 to 255
and I used 150 as the power on state to the solid state relays which needed about 3 volts.
I used a Dremel to separate the power to the common side of the power outlets
because it was modifying electrical outlets to run to the lights.
I used three of the outlets to power three strings of Christmas LED lights
and I used the other one to power the Arduino.
I'll post video of the circuit working on archive.org.
I had to pull out the audio though because otherwise it would have been a copyright violation.
Thank you for listening. There's been Ardui 72.
You've been listening to Hacker Public Radio at Hacker Public Radio.org.
We are a community podcast network that releases shows every weekday Monday through Friday.
Today's show, like all our shows, was contributed by an HPR listener like yourself.
If you ever thought of recording a podcast and click on our contributing to find out how easy it really is.
Hacker Public Radio was founded by the digital dog pound and the Infonomicon Computer Club
and is part of the binary revolution at binwreff.com.
If you have comments on today's show, please email the host directly, leave a comment on the website
or record a follow-up episode yourself.
Unless otherwise stated, today's show is released on the create of comments,
attribution, share a life, 3.0 license.