Digital Sparkle Collar

2025-Apr-02, Wednesday 01:00 am
History )

Collar )

Circuit )

Attachment )

Putting it all together )

Finishing touches )

Coding )

Testing )


Photo of the neopixel collar, closed, and turned on, with four wires meeting in the middle, leading to the Gemma in a translucent bright green 3d printed circular case, inside yet another in a translucent bright green 3d printed circular case, with the LEDs in various shades of green, yellow, white, and off.

Digital Sparkle Collar, with more robust case situation
Photo by [personal profile] chebe

Piano LED Visualizer

2021-Apr-21, Wednesday 06:30 pm
Every so often I take a fancy to the idea of taking up the piano again. I was going through one of these spells when I came across this project, the Piano LED Visualizer. How could I not give it a go?

I ordered the suggested Waveshare LCD TFT 1.44" 128x128px, WS2812B LED Strip (144 per metre), 5V 6A power supply, silica tube strip in T0515 for 12mm in 2m length, and iConnectivity mio midi-to-usb cable. (I had a cable already, but thought it wasn't working. Turns out the port labels on my piano are backwards. (If I keep writing it everywhere maybe I'll actually remember next time.)) I already had the Raspberry Pi Zero, and miscellaneous components. As well as a digital piano. Time to get soldering.

I know the instructions say there's no need to solder, but I did anyway. I used a Pico hat hacker board and soldered the connections on to it. The idea is to wire up the power between the LEDs and Pi as in this article. Checking the pinout that looks like Data out on pin 12, and I used pin 34 for common ground. Then soldered a few connectors/adapters, before seating the Waveshare on top, installing the software, etc.

At this point it all works, but it's a loose bundle of components, so let's make that case. The instructions really gloss over this part. The case is this model, but it's based off this original case for PinkyPi. Which is where I found the guide that finally told me I needed M2.5 screws, standoffs, and nuts to assemble everything together. (The direction pad button is wonderful, but the other ones did not work for me at all. At least I can still reach the buttons through the opening in the case.)

I also ordered the midi usb-to-usb adapter needed to try the Synthesia feature, but haven't had a chance to try it out (due to a major mix up in shipping, that the seller was great at getting sorted out, but it took a while).

Overall the LEDs lighting up next to the key you pressed is neat. And you can set the LEDs to play animations if you just want background lighting, say for a video chat. But the LEDs don't line up well. I don't know if it's just because I got a cheap set of LEDs, but they are off at each edge of the keyboard by a couple of keys. Overall this feels like an early version project, but all the important parts are there. Including the software which is fairly solid. And it's very fun to play with.

Photos )



Piano LED Visualizer in rainbow demo pattern
Photo by [personal profile] chebe

I find myself wanting to use the same hardware controls in different projects again and again. But in various configurations. Can I make something modular, that I can reuse as needed?

Let's take the Colour Stealing circuit, actually let's take the version with a microphone.

Details )

Here's the whole system; wrist controller connected to power regulation and signal level shifter board and NeoPixel matrix. For the longer runs of wire I'm using thicker silicone wire that I have loosely plaited.

Overall it has the same problem as watches, in that the heavier section has a habit of shifting around, but if it annoys too much I suppose I could always stick it in place. The nice thing is that it all disassembles cleanly, making everything (not soldered to the protoboard) reusable.



Wrist Controller in the middle of it all
Photo by [personal profile] chebe



As I do more with electronics I get more complicated ideas, which necessitate learning more. At the moment I want to run 5V NeoPixels from a 3.3V microcontroller (i.e. Arduino Lilypad) which doesn't have a handy MOSFET pin (like the Adafruit Flora). I studied the NeoPixel best practices guide repeatedly. The new requirements boiled down to;

- 300 to 500 Ohm resistor on the Data In line of NeoPixel strip (which will be added to the NeoPixel end),
- capacitor (1000 µF, 6.3V or higher) across the battery terminals,
- logic shifter to up the 3.3V Data Out from the microcontroller to the 5V Data In for the NeoPixels.

Okay, great. Now where am I going to get the 5Vs from? 4AA rechargeable batteries would give me 4 x 1.2V = 4.8Vs, great. But, what if I accidentally grab alkaline batteries by mistake? That would result in 4 x 1.5V = 6Vs. Which is enough to damage the NeoPixels. To protect against thoughtlessness I would need a 5V voltage regulator. But, hang on, why don't I also add a 3.3V voltage regulator and remove the need to power the microcontroller with a separate power source? Just have to make sure everything has a common Ground.

Great, okay, so that's two voltage regulators. And the recommended bypass capacitors; 1µF on input and 0.1µF on output. This is a lot. Let's sketch it out. A few times by hand, then in Fritzing.

Process )

Then it's time to commit it to solder. It all fits on a half-size breadboard, and you can use any, but the ElectroCookie board has a continuous ground line if you bridge the break, which saves me work. Also, bonus cuteness.



Finished circuit soldered
Photo by [personal profile] chebe



Testing )
This started with wanting a new outfit for EMFcamp. EMFcamp ended up being cancelled this year, but the project had begun (in earnest at SciHackDay), so I had to finish it (at campGNDd). At least I'll be real prepared for 2022.

Once upon a time I made a 7x7 blue LED matrix grid top, with LED beads and conductive thread. (I've since misplaced it. *sad face*) I wanted something similar, but green, and that could survive hanging out in a field for several days. I've learnt a few things in the last *checks* ten years, so wanted to upgrade things a bit.

First things first; RGB LEDs. Single colour LEDs have their place, but the limitations are rather absolute. NeoPixel Mini Buttons are the smallest breakouts available. They come in five packs (Adafruit / Pimoroni), and in fifty packs (Adafruit / Pimoroni). You simply snap them apart, and chain them up, to use. The solder pads are on the back, the usual 5V in/out, GND in/out, Data in/out.

Details, glorious details )

And here is it worn, and on. Again you can see the grid conforming to my body rather than constricting it. You can also see that I only have it attached at the top two corners. The grid is so flexible that its own weight (91g) is pulling it down in the middle. (Easily corrected by attaching more points of the top tape to the outfit.)



NeoPixel grid worn, under semi-sheer black tshirt, on, displaying rainbow pattern
Photo by [personal profile] chebe



So it's flexible, it's versatile, but how durable is it? This is the first version, so we'll have to wait and see.
Following on from the RGBW upgrade the lightbox just needed some finishing touches. I finally got my Feather 32u4 Bluefruit LE (Adafruit / Pimoroni) working. Hint; you need the example code at the very bottom of this tutorial page, it has all the bits and pieces actually hooked up. The other code just prints hex code to serial, doesn't actually set any NeoPixels.

I first tweaked this code to work with RGBW strips instead of RGB;
//Adafruit_NeoPixel pixel = Adafruit_NeoPixel(NUMPIXELS, PIN);
Adafruit_NeoPixel pixel = Adafruit_NeoPixel(NUMPIXELS, PIN, NEO_GRBW + NEO_KHZ800);

//pixel.Color(255, 255, 255)
pixel.Color(0, 0, 0, 255)


Then I set about changing the behaviour. This is first and foremost a lamp, so I set the default behaviour upon power-on to be white with medium brightness. Then I played around with what the buttons in the app would do. I can increase/decrease brightness, reset to default, pick a colour, and play a couple of animations, all in software. Which seems to meet my needs nicely.

Finally I soldered some headers onto the Feather pins for modularity.

The next issue was making the power convenient. Which in this case means mostly mains powered, but not permanently removing the battery option. Also sturdy, and not the slightest bit fiddly. I went with a barrel jack to JST cable (SparkFun / ProtoPic) for inside the lightbox, and barrel jack to USB cable (SparkFun / ProtoPic) for outside the lightbox. I also added a USB cable with switch (Adafruit / Pimoroni) to the mix for even more usability.

The barrel jack to JST cable needed a hole drilled in the case. Flush so it wouldn't leak light, or get in the way when using batteries instead. I used a rotary tool to drill out a nice little circle.

Details )

Then it's just a case of closing everything up again, plugging the whole thing in to mains, and enjoying.



Lightbox with new mains-via-USB power cable
Photo by [personal profile] chebe

Lightbox RGBW Upgrade

2019-Sep-06, Friday 06:25 pm
I'm wandering around a supermarket when I spot an A4 lightbox. The kind I see in many bars and youtube videos; backlit with white LEDs, a plastic diffuser, and slots for placing plastic tiles with letters written on them. It's a nice idea, restrained, classy. Requires 6 AA batteries. 6?! That's 9 volts. For 18 white LEDs? I needed to see what was going on inside.



Original lightbox, out of packaging
Photo by [personal profile] chebe



Details )

Then finally connect the RBGW LED strip up to a microcontroller, load up the example sketch, and close up the lightbox. Oooh pretty. I have this working as a rather colourful lamp off an Arduino until I can figure out how to get my Feather 32u4 Bluefruit LE working correctly. But it can run off a 3.7V battery, or USB power. Which is a considerable improvement over 6 AAs and 9V. And with so many more colour options!



Upgraded lightbox of many colours
Photo by [personal profile] chebe



*edit* Finished in part two.

RGB Colour-Mixing Hat

2019-Jan-16, Wednesday 10:00 pm
A long time ago I acquired a hat. Some time after that, still a long time ago, I added a blue LED strip to the band. Later again I replaced the silver ribbon with a black ribbon, removed the original hat band (cutting the glue off the hat), hot-glued a felt pocket to the inside to hold the battery, and cut a slit so the wires could pass through.

But single colour LEDs? Running off a 9 volt battery? Not good enough nowadays. Enamoured with potentiometers of late, I got the idea of doing a red-green-blue plus brightness mixing board. (Bonus points for not using radio, meaning it would remain functional at maker/hacker meetups where radio frequencies are often saturated.) I found myself in Makevember so I did up a quick breadboard prototype.

images )

But once I had that done I wanted to add extra modes, controllable by pressing the push button a number of times. The first one I added was Rainbow Cycle (I'm using the Adafruit Neopixel library rather than FastLED here).



Rainbow pattern
Photo by [personal profile] chebe



Videos )


Parts;
Hat
Adafruit Mini Skinny NeoPixel Digital RGB LED Strip, 60 LED/m
Adafruit Flora
Bakelite Perfboard
Potentiometers
10K ohm resistor
Momentary push button
Headers
Various jump leads
LiPo battery
Somehow, while making my Colour Stealing Skirt, I got the idea that I would like a headpiece to go with it. I mean, it's for EMFcamp, so go big or stay home, right? (Not at all, but I wanted to so I made excuses.) I wandered down a path of cybergoth falls for a little, but wanted something a bit more cyberpunk, and what is more punk than outrageous mohawks? But I don't have a 3D printer, or laser cutter, or CNC. How was I going to get something strong enough to stand upright, but translucent enough to light up nicely? I had an idea in my head of circles, inspired by CDs and hair rollers, but nothing else. So I took myself on a tour of hardware shops and wandered aimlessly. Eventually I found these. They come in different diameters and different heights, but these seemed just right for me.



Plastic furniture leg/wheel coasters, or floor protectors
Photo by [personal profile] chebe



Next step; how do I affix these plastic circles to my head? I wandered around youtube until I found people who use garden wire (for trailing vines and such) to make frames for costume headpieces. The idea is to shape a double-sided U-shape (one for each side of the head) out of the wire. You make the join with duct tape. I added extra supports to the top, by bending the ends to sit along existing wires, and duct tape them together.



Wire frame base
Photo by [personal profile] chebe



Then I continued in the same way down the back of my head. Aiming for a secure fit. I also wrapped the wire with ribbon (secured with super glue), not just to make it nicer, but because the duct tape glue was coming undone and the ribbon keeps pressure on all the joins.

Many details )



Wear
Photo by Jeffrey_Roe



Parts;
Galvanised Coated Garden Wire, 2mm / 12 Gauge / 5/64"
Ribbon
62mm plastic furniture leg/wheel coasters (floor protectors)
Organza scraps
Wide crinoline tubing

Potentiometer
Adafruit Flora
Adafruit Neopixel strand
3-pin JST SM Plug + Receptacle Cable Set
Adafruit Colour Sensor
LilyPad Button Board
SparkFun Microphone
I've had an idea for an elaborate electronic skirt for, literally, years now. And no matter how long I waited progress just wasn't being made. At one point I realised that EMFcamp was fast approaching and I needed something for it. So I scaled back my ambitions, found a white tulle/net skirt on sale, and got to work.

I had a few Neopixel strands laying about the house, and found to my surprise that each 20 pixel (2" pitch) strand was almost exactly the width of my skirt. Two strands would completely encircle it. Rather convenient. And I wanted to be able to set the colour of the Neopixels from things around me, so I needed a colour sensor. I also wanted a potentiometer so I could adjust the brightness depending on ambient light, and would need a button to change between modes. Oh, and a microcontroller to make it all work. Which gave me this circuit.

Details )

But white is very much not my aesthetic. Which is a large part of why I made this an underskirt. You can use this one underskirt with a variety of overskirts to achieve different effects. Here I've used a black crushed velvet skirt with uneven hem so that some of the glowing tulle/net still peeks out. In dark enough environments, there is a side benefit of seeming to exist in a puddle of light on the ground. (Which can be handy when trying to navigate a campsite.) Overall this skirt is fun, but not the most practical. Though I do foresee it coming in handy from time to time.



Skirt
Photo by [personal profile] chebe



Parts;
Fabric scraps
Petticoat
Skirt

Potentiometer
Adafruit Flora
Adafruit Neopixel strands
3-pin JST SM Plug + Receptacle Cable Set
Adafruit Colour Sensor
LilyPad Button Board

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