All posts by bneedhamia

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.

Collaboration is not Part of Making; it’s the Heart of Making

This post is about what I’ve learned about Making through the Robotic Glockenspiel project.

Even at the beginning of the project, I was “standing on the shoulders of giants“:

Continue reading Collaboration is not Part of Making; it’s the Heart of Making

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.

Continue reading Design Thinking via the Robotic Glockenspiel Project

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.

A router is a most wonderful power tool

In my previous post I pointed to my Open Source code for the project. In this post, I describe the mounting of the solenoids to the frame.

The conundrum of the project has been how to mount the solenoids to the glockenspiel. If I were a metalworker, I’d probably tap the solenoid holes and fasten them with 2mm screws into a metal strip. My 2017 future self says to design a 3D printable holder. Not knowing how to tap such tiny holes and not (yet) knowing how to design 3d printed parts, I’ve been thinking and thinking about how to mount the solenoids to wood.

One day I was wondering out loud how to fasten the solenoids, and Linda said “Why don’t you just buy a router? They’re perfect for that sort of thing.”  So I did.

I bought a Dewalt DWP611PK compact router set and a starter kit of router bits so I could route channels in a bar of wood, then mount those solenoids into those channels. I originally picked the DWP611 because it fits in a CNC router I have my eye on (but no money for yet).

My first attempt with a router was pretty sad. I had imagined that since I knew the basics I’d be fine. A few unintentionally-diagonal cuts later, I realized that making the solenoid channel cuts freehand wouldn’t work: I’d need a jig to let the router cut exactly the width channel I needed.

So using the router and a makeshift fence, I made a little height-adjustable jig.  The first attempt at the jig turned out badly, but I’m happy with the second try:

Top of router jig for cutting channels
Router jig for cutting channels (top)

jig (bottom)
jig (bottom)

If I were to make jig revision 3, I’d change a few things:

  1. use wider wood to give the router more base to glide on
  2. make the gap large enough so I can clamp the wood to be worked to the jig.
  3. use a plunge router so that the ends of the jig are solid rather than open. Doing that will make the end less likely to warp and bend apart over time.

At any rate, I made a test slot using this jig, and it turned out great!

a solenoid pressed into a routed channel
a solenoid pressed into a routed channel

Now I’ve marked the real solenoid bar, and am ready to route the 19 solenoid slots.

marking the solenoid bar
marking the solenoid bar

In my next post, I describe the last steps to a functional robotic glockenspiel.

Robotic Glockenspiel and Arduino Midi File Reader library on GitHub

In my previous post I pointed to some sources of information about how to read Midi music files. I’ve now Open Sourced my working code.

I’m a total newbie at Git, but even so I’ve managed to create repositories for the Robotic Glockenspiel and the Arduino Midi File Reader library it uses.  See My GitHub  repositories for the current state of things.

The repos are far from ready for prime time, but they have the essentials for this project-in-progress:

  • The Arduino Midi File Reader library I wrote to deliver Midi events from the file in sequence. I’m hoping others will find this library useful. It currently has no documentation at all, other than the comments in the code.
  • The Fritzing circuit diagram for the glockenspiel controller so far (no physical user interface)
  • A Bill of Materials (parts list) for the electronics and a few other things. I still need to add the wood and work out e.g., the number of conduit pipes I needed to build the 19 chimes.
  • The Robotic Glockenspiel Arduino program, as-is. It currently will play a hard-coded list of Midi files that reside on the MicroSD card, with what seems to be the correct timing (although I know it will end each song abruptly).  There’s much left to add, such as using a network card to read the playlist and the Midi files from the net, and code to control the player using a set of pushbuttons.

As an added benefit, all this is now under a real revision control system rather than being backed up nightly to my USB fob.

In my next post, I show how I mounted the solenoids to the frame.

Party On!