Category Archives: Projects

Wood-burned Glockenspiel labels

In my previous post, I scrollsawed labels for the glockenspiel buttons. This morning I tried out pyrography – wood-burning – to label the Robotic Glockenspiel buttons, using  a piece of scrap wood of the same material as the Glockenspiel box.

First I transferred the printed image to the wood using carbon paper and a stylus. I tried using an iron to transfer the pattern directly from the laser-printed paper, but found that works best (that is, at all) on inkjet prints rather than laser printing.

Pattern, carbon paper, and stylus
Pattern, carbon paper, and stylus

Next, I used a wood-burning iron to define the edges, then fill in the spaces. The result is pretty um…”rustic”, but not bad for having done almost no wood-burning before.  I’m still deciding whether I’ll go with this (pretty sloppy) or try thinner wood and my scrollsaw.

Woodburned glockenspiel labels
Woodburned glockenspiel labels

One advantage I just realized about raised, scrollsawn labels: the icons are simple enough that you can distinguish them with your fingers alone – great for people with visual impairments or for controlling it in the dark.

In my next post I return to scrollsawing the labels.

Scrollsawed button labels for the Glockenspiel

Since putting a lid on the glockenspiel case, I’ve been wrestling with exactly how to label the robotic glockenspiel buttons: If I had a laser engraver I probably would have engraved (woodburned) the labels on; sticking paper labels on could look pretty sloppy; decals sounded like a production of their own, with the risk of gumming up my printer; painting the labels would require a steady hand; woodburning by hand is another option; so is gluing on scroll-sawn raised labels.

So today I tried out my new (used) RBI Hawk 220 VS scrollsaw, that I’d cleaned up a few weeks ago.

Hawk 220 VS Scrollsaw
Hawk 220 VS Scrollsaw

Looking at the result,  I don’t think I’ll go with scrollsawn button labels: the labels look good, but I think they need to be more precise and on thinner wood. I’m also concerned that they could pop off the glockenspiel box pretty easily as I move the box about.

Scrollsawn button labels, laid on the box's wood
Scrollsawn button labels, laid on the box’s wood

By the way, the RBI Hawk is a sweeeet scrollsaw, far better than my old Sakura (knockoff of a Strong-brand saw). Even as old and worn as it is, it makes a really good cut.

The more I look at the scrollsawn labels, the better they look, but I think traced and woodburned labels will work better for the glockenspiel.

So next I’ll try transferring the labels’ pattern onto the wood  and woodburning it.

How to soften LED light with a ping pong ball

Some time ago I read that you can use a ping pong ball to soften the harsh light of an LED, so I thought I’d try it out.

Step 0: pick out a white ping pong ball.  I used a standard 40mm ball; I could have used a 35mm Foosball instead.

Step 1: make a hole in the ping pong ball to hold your LED. For a 5mm LED, an ice pick heated on a stove top is an handy tool for making that hole. I have’t tried a drill press, but that seems another possibility.

Ping Pong ball with hole for LED
Ping Pong ball with hole for LED

Step 2: set up a circuit to blink an LED, perhaps using an Arduino Pro Mini.

LED ready for the ping pong ball diffuser
LED ready for the ping pong ball diffuser

Step 3: press the ping pong ball onto the LED.  For a more permanent mechanical connection, you could glue the LED into the ping pong ball using a hot glue gun.

Step 4: Enjoy the magical, diffuse light of the LED in the ping pong ball.  You may need to turn out the lights to see it well. Have a look at my low-key YouTube video of the result.

So a ping pong ball really is a quick and easy light diffuser for your LEDs – disco time! …or you can paint pupils on them to create blinking night-creature eyes as in this video.

The glorious ping pong ball LED light diffuser
The glorious ping pong ball LED light diffuser

Putting hinges, lid on the Glockenspiel

Since fixing the sound of the chimes,  I’ve been finishing the software for the glockenspiel. Now all the buttons work: on/off, play/pause, skip back, skip forward, and shuffle. Woohoo!

Today I made the lid, attached the molding on the edges of the lid, attached the piano hinge and attached the side hinges. It’s not fine furniture, but I’m learning a lot about how to make The Real Thing. For example, don’t sand the wood with the sandpaper you used to remove rust from your new scrollsaw (ouch!).

All the hardware (except the front latch and the feet, which should install easity) is now installed.  So now I’ve taken all the hardware off so I can easily do the labels and spray the finish.

Next I plan to label the buttons – I plan to try woodburning – the end is in sight!

The lid is built
The lid is built

Silicone pads make a lovely sound

Now that the control buttons are in the circuit, I’ve tamed the clanking noise of the Robotic Glockenspiel! Hear it in this YouTube video.

In an earlier post I mentioned that I’d used a tube of silicone to put a drop of silicone on each solenoid, to reduce the loud ‘clank’ when the solenoid strikes the chime. I found out that a drop of silicone is way too much: the chimes hardly sounded at all.

Too-thick silicone. It damps the chime too much
Too-thick silicone. It damps the chime too much

I then found these fabulous 21-gauge glue syringes on Amazon. They’re perfect for painting just the right amount of silicone on the tip of the solenoid. They’re easy to use: pop the syringe open, squeeze a little (very little) silicone out of the tube into the syringe, touch the tip of the syringe ‘needle’ (really a thin metal tube) to the solenoid tip, then gently squeeze the syringe plunger as you paint the silicone onto the solenoid tip.

silicone and glue syringes: the path to success
silicone and glue syringes: the path to success

The photo below shows the result: a pad of silicone that’s about 1/2 the thickness of the drop shown above. I still have to experiment / adjust a bit: I thought I painted all the solenoids with about the same amount of silicone, but the chimes sound very different from each other. I suspect that I just have to be more careful about painting exactly the same amount of silicone on each solenoid.

Silicone applied with the glue syringe: just right
Silicone applied with the glue syringe: just right

Next I build a lid for the box.

The first switch is in

Since my last post about the glockenspiel, I’ve been taking a vacation from my vacation (aka working). Today I turned back to the glockenspiel and wired up the first of the 5 lighted switches.

The hardware is lighted buttons from Sparkfun in various colors, some 4-wire phone cable I bought years ago, and 4-conductor 0.1″ connectors. The heat-shrink tubing keeps the 5 pins of the button from shorting to each other. Two wires run the LED, and the other three make up the button (common, normally open, and the unused normally closed).

lighted button
lighted button
connector for the lighted button
connector for the lighted button

I had a little trouble reading the switch: whatever I did, the output was close to ground. After much experimentation, I realized that the pin I was using (pin 52) is used on the Arduino Mega 2560 for part of the SPI bus.  Once I moved the input to an unused pin, it worked like a charm, with the internal pull-up resistor to keep the parts count nicely low.

The result: push the button and the light comes on!
The result: push the button and the light comes on!

Next I improve the clanking sound with silicone.

Design Thinking via the Robotic Glockenspiel Project

Now that the glockenspiel is working and in a case, this post is about what I’ve learned about Design Thinking through my Robotic Glockenspiel project.

Caveat: since I didn’t apply formal Design Thinking to the project, I’m going to be shamelessly revisionistic in order to talk about how the project would have been better via Design Thinking.

Design Thinking process (Stanford)
Design Thinking process (Stanford)

The Design Thinking steps we use at work are labeled a little differently from the picture:

  • Gain Empathy
  • Develop Insights
  • Ideate
  • Get Feedback
  • Prototype
  • Test

A brief history of the project

  1. I was a music nerd as a toddler, then a band geek in late grade school and early Jr. High; then a vocalist from late Jr. High through adulthood. I love music.
  2. In the deep past I was charmed by music boxes and by The Mighty Wurlitzer at The Organ Grinder pizza in Portland Oregon.
  3. In 2003 I wrote a project note something like “make a circuit to play a toy xylophone”. And there it sat for years, awaiting something to help break through the inertia. I’d used Pic chips, but they were time consuming to use. I’d fiddled a little with Arduino, but hadn’t devoted any serious time to it.
  4. In 2014 I spent some mad money on an Arduino Starter Kit, and had a grand time going through the exercises in it.
    • During this time I started to post YouTube videos of the projects. This was the beginning of my blogging about projects.

      My first YouTube Project video
      My first YouTube Project video
  5. As my Intel Sabbatical (8 weeks of vacation) started looming, I decided I wanted to build a Robotic Glockenspiel with part of that time. I started learning circuits I needed, and how to tune chimes.
  6. I spent the last few weeks of my Sabbatical feverishly working on the project; then spent much of my Christmas vacation getting it to a point where it would work. I blogged the project as I went, and put the project code, music, and materials list under GitHub.
  7. There’s plenty left to do, but enough is done to talk about it. You can see and hear the chimes.

The project though the lens of Design Thinking

  • Gain Empathy: I wanted to build it for myself. I thought I knew what I wanted, but I didn’t really examine it any more than any hobbyist. Also, only later did I realize that there were a couple more audiences: 1) my wife, family, and friends, 2) other Makers and musicians, and 3) my co-workers. I only talked with my wife about what we might do with it after it (the first version) was playing music.
  • Develop Insights: Early on I did actually spend time thinking about what music I wanted to play: Public Domain Christmas Carols, mostly from the Oxford Book of Carols. Looking at specific carols led me to design a chromatic scale with a large (1.5 octave) range, rather than the 8-note Major-scale many hobbyists have built. I also knew I wanted to play MIDI files that I could create with an open source MIDI editor. Originally I wanted to play playlists and Midi files from the net, but later realized that playing them locally (from an SD card) fit better into the model of setting it up somewhere and having it play.
  • Ideate:  I didn’t spend much time ideating: creating alternative physical designs and interactions beyond the single design I could think of: a thing that looked like a xylophone in a box, with an Arduino playing it from a playlist and MIDI files on an SD card.
  • Prototype, Test: Here’s where most engineers want to start the process: Skip the understanding and alternatives, and jump straight into building stuff. In retrospect,this is the bulk of the work I did – so it’s clear I fell into the trap of the engineer’s approach rather than the designer’s approach.
    • I tried out several types of chimes cut from different metals, and settled on 1/2″ conduit.
    • I tried out a couple ways of cutting the chimes to length and tuning them, settling on a pipe-cutter, rough metal file, and my ukulele tuner – this worked great. My first narrative blog was about cutting and tuning chimes.
    • I built a few test chime mountings, to see if the chimes would ring properly. I tried 2 ways of mounting the set of chimes, because my first attempt failed miserably.
    • I experimented a bit in mounting the solenoids, mainly because I’d just bought a router and didn’t really know how to use it yet.
    • I made a test circuit before too long, to make sure the power supply would ring all the chimes at a usable volume.
    • The software development went pretty smoothly, because I’m a software engineer by training.  …although I did get thrown a bit by Arduino interfacing (I forgot to write a blog entry on that). …and I changed the design a few times once I started thinking about making the project Open Source.
    • I waited until the mounting and circuit were done before I designed (or even thought much about) the box the whole thing would go into. As a result, the box is huge and unwieldy.
  • Get Feedback: Once the glockenspiel played tunes, I showed it off to Linda and we talked about how we might use it. This would have been a great conversation to have before I started – doh! We now think the best use would be 1) as a doorbell that plays tunes appropriate to the time of year, or 2) as a quiet music box that plays in the background at Christmas parties.  We also learned a few things from this first prototype:
    • It’s huge. I need to build a totally different, more compact frame. It’s bigger than a card table, and certainly can’t be discreetly tucked away as a doorbell.
    • It’s loud; perhaps literally deafening. I’ve experimented a bit with dampening the clanking, and have more experiments to do.
    • There’s no way to control it. After it started playing, I realised it needed at least Pause, Stop, and Skip buttons.
    • I generally like how it turned out: The circuit works, it sounds pretty good and is nicely in tune, it’s easy to make MIDI files for it to play, and easy to edit the playlist.

So even though the project was mostly for my own enjoyment – a situation where you’d be tempted to skip parts of Design Thinking, I could have made a much better first working prototype by  formally following the process: Gaining Empathy (looking into our lives and music); Developing Insights (analyzing how such a music box might fit into our lives and our house);  Ideating (coming up with multiple designs for a music box / doorbell)); prototyping and Getting Feedback through low-fidelity prototypes that would let us pretend we’re using it.

I’m sold on Design Thinking. I’ll be using it in the next project (or iteration of this one).

Next I start putting the control buttons into the circuit.

It’s all in the box (except the buttons)

In my previous post, I started putting the glockenspiel case together. Now I’ve bolted the glockenspiel harp and circuit boards into the base of the box, and temporarily mounted the handles and buttons. I still need to wire up the buttons.

assembled glockenspiel
assembled glockenspiel

In other news, I’ve tried out various ways of damping the initial, loud “clank” when a solenoid strikes a chime.  A piece of scotch tape on the top of the solenoid had no effect at all; a dab of silicone (which someone else suggested) can make just the right sound, but I’m a little puzzled about how to repeatably put just the right amount of silicone on each solenoid.

A daub of silicone on a solenoid. The silicone is about 2x as deep as it needs to be.
A daub of silicone on a solenoid. The silicone is about 2x as deep as it needs to be.

In my next post I reflect on how Design Thinking could have improved the project.

Gluing the Glockenspiel box

Now that the glockenspiel plays a number of Christmas carols, it’s time to put it in a box.

After a pile of routing I’m now nailing and gluing the Robotic Glockenspiel box together.  Since this is a first prototype (the flat chime harp is too large to be practical), I’ve made the box sides from 3/4″ x 6″ “white wood” (fir or pine) instead of hardwoods, and made no attempt to conceal the nails.

Gluing and nailing the glockenspiel box
Gluing and nailing the glockenspiel box

The base and top of the box are 1/2″ plywood with a nice veneer; the sides are fir/pine. The base is held in place by 1/2″ wide and 3/8″ deep dado joints in each side; the ends are connected via rabbet joints (which you can see in the photo). I’ve routed holes in the front for the 5 buttons that will control the glockenspiel, and scroll-sawn holes in the back to plug in power and usb cables.  I also used a flush trim router bit to make all the sides the same height (for some reason one of the boards I bought was about 1/16″ wider than the other).

I’d hoped to plug/unplug the SD card from the back, but found the thickness of the box walls would require a huge hole to get to the SD card. So instead I cut a small hole, then decided to plug/unplug the SD card from the inside.

I plan to connect the lid via a 30″ cabinet hinge from Lowes. I’ve routed out an indentation in the back of the box so the hinge will be flush with the top of the box.

Since this weekend is the end of my end-of-year vacation, progress on the glockenspiel will likely be a lot slower from now on.

The next step is to drill all the mounting holes, put a clear finish on the box, then mount the chimes and circuit inside the box. I plan to figure out the lid later.

Robotic Glockenspiel now plays 17 Carols

In my previous post, the robotic glockenspiel played its first tune. This post is an update on transcribing more tunes.

I’ve been busily transcribing public domain Christmas carols from “The Oxford Book of Carols” and other sources of public domain carols, so the glockenspiel has more material to play. All the carols are checked into the SD folder of the Robotic Glockenspiel Git repository, and are part of that open source project.

In other news, I bought this edge guide for my router, so now I can cut the grooves that will hold the base of the glockenspiel.  Next I need to learn how to make rabbet joints, so I can put the glockenspiel box together.

My next post is about crafting the cabinet for the glockenspiel.