Hi! I was wondering if you can help me plan a project.
I’ve had a small amount of experience a few years ago, self-teaching using forums etc, to animate artworks using servo motors using Arduino UNO. As gateway project for getting back into artmaking I was hoping to make small battery-powered disco lights to attach to the bottom of my roller-skates. I’d love it to be small and neat on the bottom of my skates (e.g. 55x21mm is the perfect size to sit between the trucks of the skates, which is the size of a 9v battery holder for reference). I have access to a 3D printer so could make a case at a later stage once I work out all the electronic bits.
I am very beginner but keen to tinker to work it all out! I just want the right components at hand and probably some hand-holding so that I don’t accidentally blow anything up.
I’d love your advice on what I should get to plan this out? I was a bit trigger happy and bought a few things as a starting point, before realising I don’t know what I’m doing. I have two Trinket Pro 5V and 20 individual neo pixel minis. I was hoping to make something like this truck-riser project, though it doesn’t need the bluetooth component — just a on/off switch or a button to move through different light modes would be great.
TL;DR: Could you please help me plan what I need to make two battery powered devices — one for each skate — which have 5-10 neopixels facing down to light up the ground beneath the skates. I’m open to using individual neopixels or a stick or a ring, it doesn’t need to be contained in a case but I’d be happy to tinker with this truck-risers project to make that case work for me. Ideally the project would end up 55mm long (between the trucks), up to around 25mm tall (between bottom of skates and the ground), and up to 120mm wide across the width of the foot. It can be rechargeable lithium battery or a 9V, I’d like your advice on that. It doesn’t need to be in a case —e.g. it could look like this but I’ve got access to a 3D printer if I can make a little case to go with it later.
These two projects describe the kind of thing that I’d like:
The Trinkets are great tiny microcontrollers, they dont have onboard BlueTooth like the nRF module used in the truck riser project.
Before you jump into putting them on the skates I would do some experimentation on the bench using some small sticks or GlowBits (Hopefully the 1x8 sticks hit the store soon!)
For powering the LED’s you can use the USB pin on the Trinket to get power out (Pinout reference)
For powering projects my goto are 5V battery packs from Kmart or larger ones from Core: https://core-electronics.com.au/power-batteries/usb-battery-packs.html
I’d have a look at using a dual output one so you can supply power to both - also might be worth to keep the batteries off the ground (a side pocket would be good) away from anywhere it can get punctured or heat can build up from friction, especially LiPo’s!
Along with the strips, controller board (Trinket) you’ll need a couple micro USB cables, some wire to solder everything together, a button to change the modes.
I’d also have a look at making the LED’s a bit more hardy, epoxy, a cut up Chinese container etc… Bringing the controller board and button up to the front of the skate might also give you a bit more room underneath while still letting you do crossovers.
Thank you for your detailed response Liam! I have a lot of ~I am an extreme beginner~ style questions. With the 5V battery packs, they’re those little emergency phone charging style ones you find in vending machines at train stations yeah? Would you have this instead of a LiPoly battery onboard, attached to the controller board via a microUSB cable? Or do you mean to say you’d have it as a backup to charge the batteries? Because when you say dual output I’m imagining wires running up the legs – is that so? I’d rather have a lightweight and compact battery on each skate. Therefore if I were powering skates I’d have to have two battery packs – one on each skate – which might be a little heavy and bulky, I’m not sure?
So another question: if I do an onboard little lithium battery like in the truck riser project – I’ve noticed that the Trinket doesn’t have a USB power charging circuit – does this mean I’ll need a LiPoly backpack to make it work with the battery?
Yeah, those are the ones. Yup, I’d completely swap them out. it also allows you to drop the Powerboost board(link and reference later in this reply) and feed the power through the Trinket and use the power from the USB pin ( you’ll have access to more than 500mA).
I’m coming from it from a safety perspective rather than electronically, those packs protect the batteries, have the BMS and charging circuitry built into it, plus with running LED’s you’ll be safe from them automatically turning off (The guys at Core might be able to do some testing to see what the average shutoff is for each pack)
Yeah I was thinking wires down each leg, Fair enough, LiPo’s are very energy dense, but that also wraps into safety, making them quickly removable so you dont get hurt could be a route to explore.
Yeah, to bump the voltage up from the 4.2V - 3.7V that the LiPo outputs (as the battery discharges the voltage changes) you would use a boost regulator to bump it up to the voltage, this is where the Powerboost is handy it lets you charge the LiPo with a USB cable and lets you know when the battery is low (there isnt any protection onboard so be careful!)
Cool I like these ideas. Theoretically it would be cool if I was skating with flames on my feet, but in the field I’m not so sure. And after a bit of research… the battery packs are small enough that they’d probably fit underneath the skates and be protected by the wheels!? I’ll have a play and see.
The Glow Bits are very sweet! Thanks for that tip.
Oooh that would be awesome, surely on concrete you’d be fine. You might get some looks and questions from people. Coming from ice skating I’ve seen something similar at the rink, it looked to be a part of the skate itself though.
Good catch! I’d love to see it finished
No worries, if you have any other questions feel free to pop them up!
I got a GlowBit rainbow as Liam suggested, and it’s very cute! I also got some hook test-leads for prototyping. I have an arduino uno I’m already familiar with. And a breadboard. And an ill-organised small mountain of boxes of bits and bobs. READY TO ROLL.
Third snag: trying to work out what type of resistor I had based on the little coloured lines on them
Fourth snag: code wasn’t uploading to uno successfully. answer: was trying to upload to the wrong port. in arduino IDE go to menu bar, tools>port>arduino uno
Here is a less-than-helpful photo of the configuration that’s working so far. Note!!: Not pictured plugged into power, I moved the yellow lead to pin 6, and ignore the little button.
Great to see you working your way through the challenges one step at a time.
Thanks for providing a photo with your update, this looks like great progress for a proof-of-concept roller skate disco lights so far
Our production team did some quick testing of the white USB battery banks Liam linked and it looks like they’re happy to keep supplying power with a low current load, so they should be a great option for a compact and reasonably resiliant power supply that won’t require a tonne of extra protection circuitry.
Awesome, thanks! I actually ran out and bought a couple of generic $4 power banks from the office supply shop at the end of my street – I’ll let you know if they work. They also happen to fit nicely to the underside of my skate boot and quite light (I think 100g each)
Thanks for doing that testing. For reference: I did a little bit of reading earlier and found that the fancier powerbanks can have a function that turns off the power supply if there isn’t sufficient current being drawn from them when turned on – I think that’s what you’re referring to?
This is a lovely community. I appreciate your time and support! Keen to get these wheels flashing
Exactly, I know my Goal Zero bank does and I think one of the brands from JB HiFi does the same, so we wanted to see if ours did too, but with some quick testing it appears they do not.
