Friday, December 3, 2021

Christmas Tree Project Step 1: Materials

Early this year, I watched a video by Matt Parker on his project to make a Christmas tree with LED lights. The lights were individually addressable and he mapped their 3D coordinates so he could make effects that followed the tree rather than the wire of the Christmas lights. I was instantly inspired to make something similar. However, I didn't actually see the video until after the holiday season (which is when he posted a follow-up in which he runs people's code on it), so it didn't really make sense to do so at that time.

I'm not usually one who remembers to follow up on such ideas at the right time, but somehow I ended up at the video again a while ago, which was nicely just before Christmas. This time I was in the perfect position to actually make one myself.

Now, Matt has an important tip in his video for projects like this (in a much broader sense): start small cheap. That's not something I'm good at. I like to start on something really big and ambitious and work towards a grandiose goal, and not care too much about the money I'm spending on whatever new project I'm working on. It happens a lot that I then do not finish the project, but that's just something that I've made my peace with. However, I was also struggling with the fact that if I ordered the lights from an affordable place, I might not actually receive them until after Christmas. So, that's why I decided to go back to his tip and actually follow him.

I actually already owned most of the things I needed for the project. About two years ago, I was similarly inspired by a video on YouTube for another project involving Christmas lights, so I had ordered a string similar to the one Matt used, but I never ended up doing anything with them, so I still had them. I also have plenty SBCs and microcontrollers, so that wasn't going to be a problem either. The one thing I still needed was a tree.

The lights

In the video, the simple start was one with a clothes rack standing in for a tree. I didn't want to go quite that simple, I wanted to make a "Minimal Viable Product" this year and then I can see if I want to go bigger and better next year. I did want an artificial tree, though, as I don't want to deal with the mess and I want to make something that I can just retrieve next year (if I don't end up going bigger). I also didn't mind spending a little money on a tree because it was the only part of the project that would cost money. So, I visited a physical store and bought myself a 90cm (2'11") tree.

A 1.5L bottle of Pepsi for scale because I didn't have a banana

The next challenge was the power adapter. It turned out that that I actually had a lot more of those than I thought I did. However, almost all of them were 12V or above, and the lights needed 5V. One adapter that was 5V only supplied 1.2A. Now, the string is going to need about 3A when all lights are fully lit. I can probably get away with a bit less, but 1.2A seemed like it might be pushing it a bit. One other adapter was rated 5V and 3A which is perfect, but it had the drawback that it was a micro-usb cable that had snuck in with my barrel connector adapters.

One clutter of adapters

Micro-usb cables have two problems. The first is that it's not at all easy to connect to the power lines unless you have a proper connector. That problem disappeared when I realized that I had some micro-usb breakout boards that I can use for this. The second problem is that they are pretty infamous for not reaching the Amperage they are rated for. However, I also had a solution for that: tools to see how the adapter does if you draw up to 2A. That wasn't the full 3A, but it would still give me a good idea if the adapter was likely to work.

1.8 Amps...

As it turned out, the adapter fell well short of the 3A with only about 1.8A, but that was at least an amount that is likely to work as I have all my leds go on full white. And if it doesn't work, the advantage of using the micro-usb break-out board is that I can probably find other cables to use, either in my own possession or in a store.

The micro-usb break-out boards

With all the components collected, I guess the only thing left for me to do is to say that this story is... to be continued.

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