Baby Dragon

For Halloween, my son told me that he wanted to be a dragon. What kind? I asked.

A fire breathing one.

Since small children with flamethrowers are generally frowned upon, he settled for sound reactive lights.

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I am a busy person, so whatever shortcuts could be thrown at this costume, got thrown at them. First off, black trousers, red sweatshirt, base done. Secondly twitter informed me that articulated dragon wings are a Thing on the internet, so a set of those got purchased pretty sharpish. Luckily Child does not like having anything on his face, whether that be makeup or masks, so it was down to whatever I could figure out to whack on over the sweatshirt.

The design appeared, scribbled by me while Child looked on and corrected me. Frequently.

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And this is how we ended up with this implausibly detailed design.

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The idea is that there’s an Adafruit Circuit Playground Express on the chest, set to detect sounds, and then fire off er, fire-coloured lights over the front of the costume. The other part is that he wanted to actually code the lights, so I was limited to the microcontrollers he had experience of – it was that or the Micro:bit.

The lovely thing about the Circuit Playground is that you can code it at least three ways – MakeCode, Circuit Python, and that other thing. You know, that one.

More on that later.

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As I’m sure everyone does, I wrapped half of Child in chip paper (Americans, it’s the outer layer of what fish and chips is wrapped in. The inner layer is too greasy.) and drew where the chest plate should go. The shoulder plates were fashioned out of the recycling (cereal packets) and tested for flexibility.

Then I marked the pieces out onto the back of some red glitter felt, cut them out and hit a snag. I wanted to pin the shoulder plates together with paper fasteners, but we didn’t have any, so I improvised. Turns out bent paperclips work just fine.

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Chest plate next.

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We did a lot of umming and aahing at this point, as the glittery red didn’t contrast very well with the sweatshirt. I focused on the positioning of the Circuit Playground and the lights while that got mulled over.

I cut a diamond/rhombus shape out of mdf, with a hole for the Circuit Playground to fit in snugly, before realising that wires are a fairly important part of the setup. Cue a bit of filing.

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I gave the MDF a coat of primer, and set an orange perspex diffuser into the hole, and tested this out with the pumpkin candle tutorial from Adafruit to see how it looked. Pretty good, I thought.

There was a problem though. The diffuser meant that the microphone/sound sensor on the board wasn’t picking up enough of a difference between a moving child with rustling clothes, and a roaring child who was pretending to be a dragon. All sorts of misfires (pardon the pun) meant a redesign.

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And then… into my life appeared this AMAZING dragon scale material. Couldn’t not use it, as it was both scaly and black (and thusly contrasted with the sweatshirt perfectly).

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Enter the next three nights of my life, soldering these little things onto snippets of wire to fit on the pattern I’d drawn. Layouts are very important so that you don’t end up with too short a join, or an impossible bridge.

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Exactly why I sat down and drew it first, before cutting all those little bits of wire. Sadly, my brain hadn’t registered that I was looking at the inside of the chest plate, and that the Circuit Playground would be facing outwards. [insert facepalm here]

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Note the complete flip of the pins. D’oh!

I still hadn’t noticed, so I commenced snipping the wires to the right length and then soldering them at the right angles. I was feeling quite smug at this point.

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And now all I had to do was fit the Circuit Playground onto the wired LED chest plate and… oh. I think I stopped taking photos at this point as I frantically rewired the start of each strand to the correct side of things, so as a consolation prize here’s a very ugly photo of my idea of securing wiring to the back of something where you know no one will see it.

DSC_1446We used MakeCode to add the lights in three sections, so that we could control them in a ripple effect (marked sections 0, 1 and 2 on the paper).

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On the front, I used stick on gems as diffusers for the pixels. Surprisingly, we only lost one gem while out trick or treating!

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And finally, it’s ugly and quick but it works, we duck taped the chest plate on (the wings covered it), popped the wings over the top and bada bing bada boom – one baby dragon! When he roared, the lights lit up from bottom to top in a kind of ripple effect, and as you can see in the last photo, it was enough to light the way for him and his friends when trick or treating.

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Xmas dress 2017

For our Christmas do, I usually do something along the lines of …well, lights. In my family we have always celebrated the Solstice and the sun coming back, because quite frankly, Winter is a bit miserable.

So, last year I wore a crown of ivy, berries, and little warm white lights.

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This year… I figured I’ve got a bit better at coding, so why not use that to make my lights a bit more interesting?

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I drew this sketch with all the enthusiasm and disregard for practicality of a 5 year old. First step was actually having a dress to put it in. Sewing is something I’m capable of, but I don’t have the patience to sew sequins on. Cue Chinese manufacturing.  Turns out if you send your measurements along with a rough sketch of what you want, then wait weeks and weeks, eventually a dress turns up.

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It also transpires that I can’t measure myself correctly, so the V shaped back is going to be a little more V-y than first planned. If you want a laugh, the zip also got stuck when I was trying it on, and I had to be helped out by a neighbour and a can of WD40. Plus point, the dress smells better now.

While I was waiting for the dress to arrive, I made up some prototypes. They kind of worked, but were a bit ugly. This version is a halloween witches’ skirt with red LEDs underneath – sort of works, and you get the idea of what I was aiming for. I wanted SNOW though. The lights on the prototype went up, not down. 😦

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It was time to be brave and dip a toe into Arduino to drive Neopixels. I got some WS2812B’s on Lorraine Underwood’s recommendation – they’re the ones she used for her awesome weather display stairs.

So, when you don’t know how to do something (in my case, ANYTHING) with an Arduino you turn to the internet. I used Adafruit’s tutorial on the Trinket to get the right libraries installed and to learn how to upload code onto a Trinket. Nothing gave off magic smoke, so all good so far.

Next, time to research falling snow patterns. My local Emporium of Shops (referred to as Meadowhell) had some great icicle patterns that appeared to drip snow. I nosied at their xmas decorations , but after a near miss with a balcony I gave up trying to look at their microcontrollers, and to be fair the security guard was giving me suspicious looks.

TO THE INTERNET!!!! I really admire the work of Kamui Cosplay – so I bought a book of Svetlana’s called Advanced Lights – Animated LEDs. You can get them from Adafruit or from her website. It’s a very fun and well written book with lots of little asides, and gave me the confidence to have a go at altering some code. Her Nova cosplay lights were based on these LED falls by Phillip Burgess, which in turn were based on these shoes by Becky Stern, so I guess my dress code is in good company.

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I looked at the colours in the LED falls and how they were set – and changed the code so that it was shades of blue, white and cyan. I also think I may have found a bug in the code on the page – you need to add the word “const” before the line about the gamma correction table (line 11).

I uploaded this code onto the Trinket, and then tested it with one strip of 15 Neopixels. BOOM! Happy times, it worked straight off. I tested it out on all of the pins in turn, from 0 to 4. Still good. Next I had to work out how to wire up the strips to be stable enough to hang around all night on a skirt and not be a horrendous fire hazard or giant tangle.

There is a guide to wiring the LED falls on the tutorial page, but I wanted mine to be a lot more spread out to go around the dress, instead of all radiating from the same point, so I grabbed some card and made an extremely poor and non technical wiring diagram.

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The warning on the Adafruit tutorial says your soldering has to be Rock Solid, so I knocked up some mounting plates for the top of each strip so that the solder joints wouldn’t be under any stress. I cut them out of 3mm scrap perspex on the laser, with mounting holes on the top, and a textured front so that when I inevitably glued the neopixel strips on with hot glue it’d have something to grip on.

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Soldering took ages because I stopped after each strip to re-test that they still did what I wanted, because there’s nothing worse than working your way through 42 solder joints and *then* finding out there’s a problem.

Next, I glued each strip to a mounting plate, and threaded a cable tie through the holes I’d cut. I then liberally taped with all up with black electrical tape, kind of to hide the joins and also because I feared bits dropping off.

The installation of electronics into the dress was a lot easier than I thought – largely due to the cable ties I nabbed off Jon, and the way that I wanted it to be removable for washing the dress. A cable tie through the mounting plate, then a safety pin through the cable tie and onto the dress. A few more cable ties sorted out any baggy wires, and then finally I pinned the board to the back, and added a USB cable so I could run the dress off a powerbank.

Yay! All was lovely. Until I plugged in the powerbank. Turns out that testing the electronics with mains power works lovely, but a powerbank just doesn’t give out enough current to light all of the strips. Yes, I should have thought of this before.

Cue a change to LiPo batteries. Which also couldn’t give enough oomph, so I had to double the price of the electronics (I’d spent £20 so far) and fork out for an Adafruit Powerboost 1000.

AND THEN IT WORKED!!!!

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I know this isn’t a very detailed write up, but I made the dress for fun, rather than for a tutorial. Maybe when I make one for the toddler in the photo I’ll do a proper tutorial.

Parts used:

  • WS2812b reel of pixels, cut into 15 pixels per strip.
  • 7.5m of black stranded wire
  • 7.5m of red stranded wire
  • one scrap proto board liberated from Botlab
  • lead free solder
  • scrap 3mm perspex
  • about 20 black cable ties
  • 5v Adafruit Trinket ( Adafruit (USA) or Pimoroni (UK)  )
  • Adafruit Powerboost 1000 ( Adafruit (USA) or Pimoroni (UK) )