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With the usual rock-band line-up of ukulele, double bass, washboard and phonofiddle, and with harmonies to die to, the Boodlum's find humour in the best and worst of popular music. They needed a new prop ...

Parts list

Qty Product Part number
1 Concertina
1 Pull Action DC D-Frame Solenoid, 7mm stroke, 5W, 6 V dc 250-0760
1 Panasonic Lithium CR2032 3V Lithium Manganese Dioxide Coin Battery 457-4757

I went to see the Boodlum Band play at my local theatre. I soon realised that they have fun with music in a similar way that I have fun with engineering - not taking it too seriously and accidentally inspiring and encouraging other people to have a go.

They are billed as "art-rockers with a unique mix of offbeat songs and comedy, and an enviable playlist that includes rock classics, old-time songs, pastiches and pop parodies."

Their instruments include watering cans, double bass, washboard, swanny whistle, ukelele, keyboard and a phonofiddle.

They wanted to introduce a new "instrument". Band member Ian English had an idea for a gag - he would be the backing concertina while another band member sang a song. And on a long note, he would pull the concertina too far, and the end would fall off. He had a concertina (technically, it's a bandoneon but you're not going to squeeze the differences out of me) and the end had already been removed - but that's where the project had reached a stop.



Could I make it so it was playable, but also would come apart on demand?

As I had never worked with a professionally-made musical instrument before, there was only one answer to that. "Of course!"

Before I started, I wanted to get a little idea of concertinas and bellows, so I adapted Rob Ive's paper puffer.

Rob Ive's Paper Bellows Photo Credit

Which was fun, but ended up to be not much like the concertina I was hacking!

The concertina had seen better days - some of the buttons were missing, some notes didn't play. So I didn't feel too bad about hacking it.



Because I didn't really know how to start, I started with the obvious things - fixing the buttons ...

Which involved making a new one. 




Painting parts with nail varnish ...



Some of the leatherwork was broken, so I repaired that too (thanks to Elizabeth Bond for advice!).

Leatherwork_ec6321bf7a2a13703b0cc19b53bb6b21d4792b3f.jpg New_leather_2_7651b46c12f74d1606c476ed730ae038837bcc0d.jpg New_leatherwork_f1682e297a56bb188c9202dcb6bdac9ca0fc0905.jpg

When there were no other distractions left, I got on with the actual project.

I had been asked for "Press a button and it releases" - so I decided on solenoids and a battery. However, no external wires were allowed.

The battery had to be small enough to fit inside the concertina. I also made sure that I could take the other end off the concertina, in case the battery ran out when it was closed.



I drilled into the case to make sockets for the solenoids to locate/lock in to.


The secret button on a switch - painted with black nail varnish ...


Secret button installed.


As can be seen in the video, everything worked perfectly.

Until I put the rest of the concertina together and tried to play it. The solenoid throw wasn't long enough to hold the end on, and air leaked out. Which meant the air didn't go through the valves and so no noise came out.

After all that effort, with such an elegant solution ... but it was not fit for purpose.

So I needed a re-think.

Opening my kitchen cupboards I realised they latched with magnets.

So disregarding the request that it had a "secret button" I put cabinet magnets and the locking plates on to the concertina, and also a gripper latch to hold it fast and stop it sliding apart.







These held it closed enough to seal the box and force the air through the valves - making noise music noise.

The concertina had its first outing at Towersey Festival in August.  The video shows a clip of it in action.

The solution is comletely mechanical, not that elegant, but it is fit for purpose.


I am an inventor, engineer, writer and presenter. Other stuff: Royal Academy of Engineering Visiting Professor of Engineering: Creativity and Communication at Brunel University London; Fellow of the Institution of Mechanical Engineers and have a PhD in bubbles; Judge on BBC Robot Wars.
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