Voice‑Activated Snowflake! Animating LEDs with a micro:bit

This video contains sequences of flashing light. Hi, I'm Natasha and welcome back to element14 presents. In this video, I'll show you how I made my LED snowflake react to my voice. This video is a continuation of my LED snowflake project. So, if you didn't see the first video, check it out at the link below. In that video, I share my design process from discovering the LED filament sticks to laying out the circuit design and soldering it all together. In this video, I'll share how I connected the circuit to micro: bit and how I experimented with the code to create these LED animations. Let's jump in.

Now, it's time to upgrade to a micro: bit and I grabbed a breadboard compatible adapter for the micro: bit out of my bin. This is something that I won't use in the final, but it already had pins soldered to it. So, I'll use this one to make a breadboard prototype and then I will use this other one that doesn't have headers on it yet to solder the final project together. I have my little jumper cables with the spring hooks and never have I been so excited to use them because look how convenient they are. Perfect. I plugged in the other end to all of the pin numbers except for five and 11 because those correspond with buttons A and B because I want to use those in the code, too. So, I've got everything lined up. Let's jump into the code.

The first thing that I did was make an array of my digital pins because they weren't all in order. So, I went in and I went to the advanced tab and went to pins and grabbed this digital pin item and then was able to select which pin and put them into each bit of the array. And then I just made a little loop going through each of the pins and turning them on and off. So, let's take a look at what that looks like.

Let me think out loud here. So, I have this center burst and that actually leads up and to the outer pieces here. So, maybe what it is the main part of the animation is going in to out and then the other pieces that aren't a part of that main bit are kind of like the secondary bits of the animation. I like this a lot better. I feel like using the center to just burst out right away makes a lot of sense and then the secondary burst is like the aftershock. So, it's like boom boom. Yeah, I like this a lot.

— Well, this is bad news. I thought that since there were so many PWM pins on the micro: bit that I could connect all seven of my LED rings and do a nice analog fade on all of them, but unfortunately, I did not read number three — in the notes here and it's telling me that I can only use three at a time. I am so angry. I thought that I could do this whole fade effect, but I need a new plan. So, I could switch to Arduino, but I already got an edge connector and I have all of the components that I want to put into this project build. So, I think what I'm going to do is just pivot to creating an animation that looks cool with these limitations. Now that I know my goal, I'll solder everything together first and then work on the final code.

— I chose this edge connector because of its shape and the ability to put the little pins over the edge of my block. I took a few pictures to make sure that I remembered which pins were which and then I disconnected everything to solder the final copper wires to the edge connector. I marked and drilled holes to connect the edge connector to the block using screws and I ended up having to use machine screws and not wood screws because they were so close to the edge of that block that I was afraid that if I used a wood screw, it would just tear through and you would see it on the side of the block. So, I do think I did the right thing by — choosing a machine screw cuz that worked just fine. Next, I used the needle nose pliers to create little hooks that I could hook around the vertical copper wires and run it back through the pin holes in the edge connector. I repeated this for all nine wires and then it was time to solder them together. Here, I just added a giant blob of solder on each of the hooks that I made to make sure that was a good connection and then I went through and soldered each of the pins to the board. And I used my flush cutters to get rid of all of that excess wire so that everything would look nice and clean. Now, my micro: bit could be inserted upside down kind of like a bat hanging there on the back of my block. But wait, oh no, my USB cable doesn't fit. Don't worry, I have a solution for this. I found these little USB turnarounds online and this one actually goes from micro to USB-C. So, not only am I making it fit into the project better, but I can use just a regular USB-C cable with my micro: bit now, which is just more convenient for me. But before I plugged that into the computer, I went through and looked for any broken LEDs. There were several. So, I decided to replace them so that I would have a fully functioning snowflake for my final coding session.

I decided to use the micro: bit's onboard microphone to provide some interactive input to the sculpture since I wanted the animation to feel alive, but keep things simple. I started by creating code that used volume to trigger the burst of LEDs that I created earlier. — I like this animation and I think I'll make it even better by using the analog pins to mimic the volume of my voice or the music and then have that burst happen only on loud sounds. So, let's try that. And what we have here is only the analog pins being mapped to the audio input, but I'm not sure it's getting me that much more interest than having the digital pin. — Now, let's say if it's over 800, do the digital pins turn on. Okay, so hello. Hi. Hello. Oh, and I forgot to turn them off again when they're done. See, I am just coding as we go. Now, it has the feeling that I'm talking to it, definitely. That like robot feel and then I go blah and it gets really bright. Let me see what that looks like with music playing. Well, my hypothesis didn't work out. I don't like how the second layer of the snowflake is — less bright than all the others. I think it looks like a mistake or that they aren't really LEDs back there, but rather just other parts of copper wire that aren't quite illuminating. Well, they wouldn't be illuminated at all if they were copper wire. So, I think I think the analog thing is kind of not that great of an idea. Maybe it's totally okay that I don't have many analog pins because this thing was meant to be animated as an on-off type of animation. — So, I started with the big burst and then added the rest of the pins to create this. — Now that the LEDs are animating, it's time to put the final build together. Testing 1 2 3.

— I can sneak up on it with my voice. It's so fun to play with this. I wish I could reach out through the internet and give you the opportunity to Maybe that'll be a future project. Internet connected snowflake and you could talk to me through the internet by illuminating my snowflake.

— Let's play some music. — Even though it looks really nice when it goes to music, it's just kind of fun to make some noise. Like whoop. Whoop. Hello. Hello. Oh, and when I laugh it goes ha ha.

— [sighs] — This project was so much fun. You will definitely see me building more things with LED noodles and filament. I really do want to make that tiara, so hopefully I can make that pretty soon. And there's so many more things that you could do with this. So tell me what you would make or if you have any ideas for me, please let me know in the element 14 community. Where do you think I should put this? I considered putting it in my window, but maybe that would be a lot for my neighbors to look at. So maybe I'll put it up on top of my drawers here. It's perfect. I love it. Thanks for watching. See you next time. Bye. —