I said it was addictive

This post is part 1 of 3 of  The Mindy Python's Confined Band

Well… since last post things got wild as usual

Yes, a simple bass would be great. And yes, the metallophone/glockenspiel could be perfected. And yes, most bands use more than 4 percussion instruments in their musics so the Percussion Kit could be extended a bit… and since some MIDI files include lyrics on a metadata track why not trying Text To Speech and have a singer? And what about that last year funny finding of doing music with pneumatics valves?

So The Mindy Python’s Confined Circus band has born.

And also yes, the software part is getting complex day after day. Thank god for open source and search engines.

So after having a basic 4-intrument Percussion Kit sorted out I decided to try a LEGO one-string instrument. Nothing fancy, just the basics: just a string and a resonance box:

It worked so I kept improving it… added an arm (neck), a longer string, some gear to adjust the tension… and got something that sounded on the bass range:

Then I reinforced the whole thing so I could play without dismantling it:

at this stage I was using a 300 cm Technic string, folded in two and twisted to increase the weight (weight, tension and length decide the note we get).

I wanted a slightly lower pitch and also a fret board with enough precision to mark 8 to 12 tones so I decided to increase the neck a bit but had to reinforce it a lot because tension was already too much. I ended with a 111 cm fret length:

Another advantage of such a long neck was having enough space to add some motors. So with a Technic Control+ hub I could have 1 motor to strum the string and 3 motors to press the string against the fret board:

I chose E, G, A and C because those were the notes used on Queen’s “Another one bites the dust’.

The code part shares most of the code of the Percussion Kit except that for the bass I don’t just map each note to a single motor action, I need to store on the hub the current state of the “fingers” to move the necessary ones for each new note command (for instance: if the bass is instructed to play ‘C’ it lowers the finger on the ‘C’ fret… if another ‘C’ follows, there is no need to move the finger but if it is a lower pitch note (like ‘E’) it needs to move the ‘C’ finger up and move the ‘E’ finger down, wait a bit for the finger to reach position and then strum the string.

With this robotic bass I am still facing some issues while strumming the string… it doesn’t sound the same as when using my fingers… and since I don’t know how to play a bass, that means a lot. I already tried hammering it instead but no luck… will probably need to find a mechanical design that moves the pick in a more complex way.

The glockenspiel

This post is part 2 of 3 of  The Mindy Python's Confined Band

So I got back to the glockenspiel, trying to use all the bars I had from PV Productions.

At first I had the idea fo making a vertical glockenspiel or lyra:

but I wasn’t happy with dynamics of the motors in this ‘solenoid-like’ configuration and decided to go with a conventional (horizontal) glockenspiel:

The sound wasn’t great but since I believed I could make it better just by adjusting the metal bars configuration I went to the the software part, mixing tools like Rosegarden, qmidiroute to find a way to proper map some MIDI songs to the limited amount of notes I had:

After hollydays, back to home, I got disappointed with the metal bars.. I could not get all them to vibrate as they should. So I ordered a real (but inexpensive) glockenspiel – it would sound as it should with the bonus of having more notes so I could better map some music files.

So a 12-bar MIDI glockpenspiel was now possible:

I’m very happy with this improvement. It still is the only non-100% LEGO instrument on the band but it allows me to play several kinds of music because most musics use at least of MIDI track that can be played on it (usually a piano or an organ but sometimes other instruments do map very well to it).

I still think I should extend the range to a 16- or even 20 bar glockenspiel but will have to wait for the other main instruments in the band to be completed because each extra hub I add requires an extra Bluetooth LE session and I am not sure how many my laptop can handle (I can add extra BLE dongles but the ‘pybricksdev’ tool doesn’t seem have a way to specify the HCI device, I guess it assumes there is just one).

The band

This post is part 3 of 3 of  The Mindy Python's Confined Band

So now that I had enough LEGO MIDI robotic instruments I could finally form a band.

So The Mindy Python’s Confined Circus band was born, playing a cover of Queen’s ‘Another bites the dust’ with just two instruments – a one-stringed bass and a 12-bar glockenspiel:

4 Technic Control+ hubs, 16 LEGO motors, 4 BLE sessions… but it needed more.

And I also need more space and time to proper join the band for jam sessions… luckily school is now physical again so my kids rooms are available during day time (as I am still working from home).

So the same cover of Queen but now with an extended Percussion Kit (a Robot Inventor hub with 6 ports allowing two more instruments than the previous version):

and also The Clash’ song “Should I Stay or Should I go”: