Busy hands | Disquiet mind

Digital Sparkle Collar

2025-04-01T20:14:33Z

( History )

( Collar )

( Circuit )

( Attachment )

( Putting it all together )

( Finishing touches )

( Coding )

( Testing )

Digital Sparkle Collar, with more robust case situation
Photo by chebe

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Divoom Pixoo LED Display Replacement

2024-05-07T14:50:15Z

Divoom Pixoo Slingbag is nice looking bag, with a 16x16 RGB LED screen in it. I was curious and wanted to look inside. (I must caution you if you buy one for yourself; there are always discounts, don't pay full price. And their after-sales marketing is often overwhelming.)

The bag is constructed well, of decent quality materials. The LED grid works very well. The app for it, on the other hand, is absolute hell. Other people have made alternative clients for them, like the DivoomClient for ESP32, Divoom Timebox Evo, but the only one I personally tried out was the Windows Diwoom client. Which worked pretty well, but made me realise the bluetooth communication isn't protected at all. If there isn't a client currently connected to the bag, there's nothing stopping anyone else from connecting and changing the displayed image. So clearly the hardware had to come out.

( Details )

Outside view of the bag, new display in place, running Rainbow example
Photo by chebe

This bag is quite eye-catching, and people have asked me questions about it whenever I've brought it out. I look forward to customising the animations, eventually. There are repos that will decode the actual animations from the app, but there doesn't seem to be a ready library for implementing them in MicroPython (I saw a promising one for CircuitPython, which alas is not MircroPython), but I'll keep investigating. Also, the original display is still functional, so that might find a use somewhere that isn't public.

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Adafruit LED Glasses basics

2024-01-04T14:46:37Z

Some time ago I got myself an Adafruit LED Glasses Starter Kit. But other than turning it on and running the example code I hadn't done much with it. Then with the return of Congress I, of course, wanted all the LEDs, so I dug it out. First things first, how am I going to wear this?

( Physical details )

Front panel and driver attached to my glasses
Photo by chebe

( Code details )

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Merry Krampus surface-mount soldering kit

2022-12-19T15:04:56Z

I'm not of an Alpine culture, I didn't know what a Krampus was, but I mean look at how cool this Merry Krampus surface-mount soldering kit looks! I wanted it. (It's also available on Tindie, but the Challenge version seems permanently sold out.) I found and ordered it last year, but it arrived in January, so I put it in a drawer until recently. I got the Challenge version, because a little challenge in your life can be good for you.

Slight hitch being, I didn't have any surface-mount soldering tools. So I had at the kit with my regular soldering tools. The instructions are thorough, and it even comes with a programmer that you need to assemble. But when I got to the point where I could program the board it just wasn't working. The LEDs at the eyes would blink, but then the Arduino IDE would complain that it couldn't communicate with the board. I emailed the creators, and was surprised when they replied, with even more detailed info to help me through the process! Seriously, they are lovely people.

I examined the circuit diagrams, figured out which pins on the board were which on the diagrams. I multi-metred my way through all the connections. It all seemed good. The next step was removing the transistors. I did not fancy that with my standard soldering iron, so I ordered a SMD Repair station (a.k.a. a very hot air gun). Before trying to remove the components I hit every single solder joint with the hot air. I couldn't see anything happening, but the plastic parts of the switches are very toasted, so stuff was happening. Then I tried programming the board, and it worked first time! My guess is I had made connections (multi-metre said so) but that they weren't good enough. Reflowing the solder must have helped strengthen the connections. After that you can add decorations and ways to attach the board to things/you. (There is also the challenge of changing the programming, but I might save that for next year.)

( Pictures )

Finished, and programmed board, all lit up
Photo by chebe

Of course, if you don't enjoy this kind of challenge you could buy the presoldered version, or even the solderless version, which is new this year. But as frustrating as it was doing this kit without the proper tools, it really does feel like an achievement to have it working!

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3D Printed, on fabric, Baubles

2022-01-02T13:42:03Z

So I'm minding my own (read: entire world's) business on twitter when a tweet by AtelDsign enters my feed. Geometric 3D printed baubles, that are printed on fabric! I had to try them!

( Details )

All four geometric shape baubles lit up with red LEDs
Photo by chebe

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CircuiTree of Lights

2020-12-13T17:19:29Z

Three years ago I posted about a little Tree of Lights that consisted of conductive paint and auto-changing RGB LEDs. Over the years I had to mend some of the connections with wire glue. But, again, this year, I found that most of the connections, all but one actually, had broken. The LED legs had physically broken the traces by pulling away from the tree-form.

So I gave in and soldered silicon wire between all the connections. As wire has much lower resistance I needed to add resistors as well. I also added proper wire connectors for ease of adding power, and added so much hot glue to try and hide the wires in the pre-existing paint traces. The main benefit of the wires is that now the whole thing runs happily off 3Vs, whereas before I was struggling to get half-decent brightness with 9Vs.

( Photos )

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3W LEDs, from Micro-controller, via MOSFETs

2020-09-06T12:45:35Z

Time to play with some super bright LEDs! (Just remember; do not look directly at them while powered.)

Kitronik have some lovely 3W LEDs (with unfortunate name) in a star shape for heat dissipation. They provide a datasheet with example circuit for 5V power source. It requires 2.2 ohm power resistors, which are new to me. But when I tried regular resistors there was a lot of smoke, so they are definitely required.

I want to control the lights from a lower voltage micro-controller, so I'm going to need some N-channel MOSFETs. This is my first time using these. The Data pin (from the Arduino) acts a switch to complete the higher power circuit that lights up the LED.

All together the circuit looks a bit like this.

( Images )

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LED wire Shamrock sign

2020-07-27T19:52:00Z

A long time ago, during Makevember I made a galvanised coated garden wire shamrock, for use as a sign at events. Here it is at Congress. To make it I printed the shape I wanted on A4 paper, put that on top of some cardboard, and used a pattern tracing wheel to transfer the outline to the cardboard. Then I cut the cardboard along that outline. And used pliers to bend and shape the wire to follow the outline of the cardboard shape. Including some feet so it could stand.

( Process )

Lit up LED shamrock sign, brightest setting
Photo by chebe

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Accelerometer data to RGB

2020-07-25T09:16:01Z

The LilyPad Accelerometer (ADXL335). I've been trying to use this for over ten years. Turns out I've misunderstood what it measures for 10 years. I had partial success with just the x-axis using Leah Buechley's code, but it has since disappeared, so I can't even be sure what it did.

I was trying to do something else, and the numbers, very strangely kept coming out to an exact 100.0, which is very wrong. So I went back to make sure the accelerometer was giving me a full value range. Which it didn't seem to be, so I went researching and found this excellent tutorial.

Although the accelerometer gives you raw values between 0 and 1023 on an analog read, it actually measures gravity acting on it as it moves around in 3D space. Converting the raw to Gs is straight-forward;
long xAcceleration = map(xRawPinValue, 0, 1023, -3.0, 3.0);

To then turn this into a colour, simply, you could map the range onto -255 to +255 (the polarity demonstrating direction of change), and then reducing that to just value of change;

int xRed = map(xAcceleration, -3.0, 3.0, -255, 255);
int absoluteXRed = abs(xRed);

Do the same for the y and z. Write to RGB LED/pixel of your choice. (Warning; movement in video is quite sudden.)

( Short video )

Sorry for the rough prototype version, I dismantled the version I made up for parts to make my tiara.

Other than light-up gloves, this could be used for rough gesture control, but doesn't give me the kind of information I needed for the thing I was trying to do as is.

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Time Cuboid

2020-04-27T19:55:42Z

I find myself, like many of us, sitting at my desk a lot. I sit there for work. I sit there again for the many video and/or voice socials that have been set up. I sit there to play games or watch films. I even clear off the computer stuff and sit there to solder and work on projects. I am, in fact, sitting there now as I write this. So basically, I sit there a lot. And it got so that I found it difficult to know what time it was, whether early or late, start of the day, or end. I know, I thought, possibly aloud, no-one will ever know, I need a clock.

But I didn't want to go buying lots of unnecessary things, or wait until my usual suppliers were back in full swing. So I dug around in the piles of boxes that comprise my electronics stash. Back at GaelHack (seven years ago) I started on a clock, but it never left the breadboard. I dusted that off, and found most of what else I needed.

( Making it all fit together )

Given the purpose of the device, and age of most of the components, I had half a mind to refer to this as a Time Capsule, but Time Cuboid seems more self-explanatory.
Overall it looks something like this;

Time Cuboid, on
Photo by chebe

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Lightbox RGBW Upgrade, part two

2019-10-20T14:39:26Z

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 chebe

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Adafruit NeoPixel Goggles Kit enhancement

2019-10-15T21:51:46Z

Get yourself one of the Adafruit NeoPixel Goggle kits, and make it up following their excellent instructions.

Adafruit NeoPixel Goggle kit made up
Photo by chebe

( Enhancements )

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Lightbox RGBW Upgrade

2019-09-06T16:31:27Z

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 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 chebe

*edit* Finished in part two.

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RGB Colour-Mixing Hat

2019-01-13T15:22:17Z

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 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

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Ghost detector

2018-10-10T22:45:49Z

Unexplained cold spots? Feeling of being watched? Could you have misbehaving tech, or ghosts? Let's build a cute little ghost detector you can leave all around you for ambient observance.

First you'll need a simple near-field tester for electromagnetic compatibility. I cut the battery holders off the back and started prodding around the circuit with a multimeter and crocodile clips.

( Explore )

I wanted the unit to be as small and neat as possible so I tried to squeeze everything in behind the LED board.

Wire up circuit into a neat package
Photo by chebe

( Build )

That's it. Now all you need to do is leave it where it will encounter electromagnetic disturbance.

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A Study: Book Light

2018-03-19T14:16:18Z

I wanted to try out a few techniques on a smaller scale;

1. feasibility of the neopixel circuit layout,
2. using conductive thread as traces,
3. light transmission through different fabrics.

And so I ended up with the slightly silly light-up bujo cover/ portable night light.

( Steps )

Much more impressive in a dark room. Coded using FastLED library, OceanColors_p palette, taken from this tutorial.

Cover, front, in dark room
Photo by chebe

Conclusions;
1. The circuit layout does work well. But, there is still a looseness to the attachment points (on the boards) that could be improved.
2. I didn't treat the edges of the conductive fabric, and although it frayed very little it did still fray. Treating the edges of the strips would help. I don't think using the conductive fabric over conductive thread was any faster, but it was less fiddly.
3. Diffusion of the neopixels is best achieved through distance from the LEDs and the covering fabric, so designs enforcing this distance would be better.

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Tree of Lights

2017-12-23T19:39:17Z

Umm... I posted this on twitter three years ago, so it's at least that old. I'm really surprised I haven't posted about it here already.

Anyway, it was a very simple project. Hanging around the hackerspace someone was giving away laser cut extras. I nabbed one, painted it in a mostly transparent metallic green. Then I took twelve RGB auto-changing LEDs, bent the legs, and perched them on each of the branch tips. I connected them all by way of conductive paint traces. My paint was quite old, a bit dry, and rather difficult to work with. I've since gone over the traces with wire glue (that you can get most places that sell soldering and pc repair gear), and that went much more smoothly. Many of the LEDs don't want to cooperate and in some cases I've had to hot glue them in place, repeatedly. I've also hot glued some wires onto the conductive paint traces at the roots to attach power. The power is unevenly distributed, but it's still pretty to look at.

Tree of Lights; RBG LEDs connected by conductive paint
Photo by chebe

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LED'd plush Cthulhu

2017-10-19T12:04:21Z

Choly Knight has a free plush Cthulhu pattern on their website that is totally adorable. (Actually, many cute plushies!) But, maybe, could be a little more terrifying? LEDs, yes, LEDs for eyes!

Also, I want to play with the Gemma M0, which is much like the previous Gemma, but it comes set up with CircuitPython, a derivative of MicroPython. So instead of installing the Arduino IDE and installing all the boards and libraries, it mounts as a USB flash drive, and you just write your python script in any text editor. Save it, unplug, and it will start running it. (Caveat; space is limited so not all libraries are on the Gemma M0. You'll have to copy over a library if it isn't there. Luckily there's lots of documentation. (And the NeoPixel library is already there.))

( Labour for the Great Old Ones! )

All hail
Photo by chebe

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4x4x4 LED Shield

2016-08-15T20:41:21Z

You know the story; you go into Maplins for solder, and you walk out with an LED Cube Shield. (It can't be just me.) Anyway, building one of these yokes seems to have become a kind of rite of passage for the makery sort. So, I made one!

( Couple of photos )

Not so straight LED Cube, completed
Photo by chebe

Pretty!

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Seasonal Winter Jumper

2016-02-19T17:16:43Z

Three *years* ago I started this project. At a Christmas Jumper Make Night for charity. It seemed like a simple idea; sew up some LEDs with some conductive thread. The first year I only got most of the felt snowflake done. The second year I got the SewIO board wired up. It wasn't until the third year that I managed to complete the circuit. And there are problems, but we'll get to that.

( Details )

All in all, except for the faintness of the LEDs, I am happy to declare this project finished.

It was pointed out that most light-up jumpers are so bright that it can hurt to look at the person wearing them, so dimmer, softer, LEDs aren't actually a bad thing. Especially as this kind of jumper is typically worn in winter, in dark pubs. That is a very good point. I just wish it was intentional.

Winter Jumper, modeled
Photo by chebe

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NeoPixel Tiara

2015-08-25T19:08:12Z

I love the Adafruit Learn site, particularly the wearables section, there are some really fun ideas in there. And when I saw the NeoPixel Tiara I knew I needed one. I had almost everything already, except the 3d-printed band.

To TOG! We downloaded the thingiverse file (tiaraHolesClose.stl), converted to gcode, and watched the LulzBot Taz print for 50 minutes. *cue montage music* It was a pretty good print, given how fine some of the detailing is, but our process needs tuning as there are artifacts, and the strands are coming apart as I touch them. Still, usable!

Robot minion making me a crown. Finally.
Photo by chebe

On to the assembly! ( Process details await )

Finally, my royal position secured
Photo by chebe

And, because the tutorial code has a nice sparkle effect to it, here's a short video.

I am going to wear this everywhere.

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Neckpiece that Predicts the Weather

2014-07-29T18:30:06Z

A time not so long ago, in this very land you're standing, some people were known to hang seaweed out to dry. Whenever the moisture in the air reached a certain level the seaweed would rehydrate; warning those around of rain.

Ruling out wearing seaweed around your neck, how can we use this knowledge to help us avoid getting wet? Thusly was the kelp neckpiece born!

Kelp neckpiece at Dublin Maker
Photo by chebe

I have already talked about parts of this project; in getting many LEDs to light up, and then getting the humidity sensor working. But to recap/elaborate;

( Wonderful details )

There you have it; a felt neckpiece that warns you it might be about the rain. I began trying to leverage the extra information (temperature and pressure) from the sensor, and fit it onto local historical weather data to more accurately predict rain, but was pulled away from such indulgent pursuits by the need to complete the other pieces.

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All the LEDs; or, Flora/Gemma and SewIOs

2014-04-06T13:48:54Z

If you follow me on twitter you may have noticed that I have been playing with getting the maximum number of LEDs for the minimum amount of microcontroller that I can. Here's a short summary.

( Pictures! Video! Text! )

I have to thank Rob for being very patient in answering all my questions. And also to note that although I'm using the Adafruit wearables, Rob has been using the LilyPad boards (including the Tiny!) with the SewIOs quite successfully. Yay for interoperability! And finally, that they don't have to be regular LEDs, you can connect anything you could normally. I think RGB pixels, and smile.

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Seasonal LED kits

2014-02-05T01:15:11Z

At TOGs birthday party (you weren't there?! You missed awesome cake!) rob showed me a new kit he's come up with for February.

( Soldering kits )

LED shamrock plaque, angled to show LEDs reflecting
Photo by chebe

*dusts off hands* Back to working out some Arduino problems...

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SEWRGB pixel graphic equalizer video

2014-01-02T10:54:22Z

partfusion, who makes the RGB pixels I'm using in a few half-finished projects, has made up a video offering tips using his pixels in a soft graphic equalizer. He goes into more technical detail than I usually do, you might find it interesting.

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