The OneTrickPony MIDI Controller
  • As the question Pops up frequently how to trigger the Shruthi while tweaking without having to connect a bulky MasterKeyboard or something else i quick and dirty made this:

    A simple Microcontroller (here a PicAxe 08M2) that scans a Button, if pressed it sends a NoteOn Message with a Note Number determined by the Pots Setting (hey, you want to check your Patch at different Notes, don’t you?), if releases sends a corresponding NoteOff Message. Its as simple as that, a OneTrickPony.

    You can find Sourcode (that compiles to 80 Byte ;-)), Schematics and further Information here

    Before you ask: Im not gonna do Kits or PCBs or Cases as this thingie is so simple everybody can do it on a piece of PerfBoard (its just 1Cap, 5 Resistors, a LED, a Pot and the MIDI-Connector….) but if anyone is interested ill send you a programmed PicAxe Chip and you can do your own OneTrickPony….

  • that’s very cool :)

    As used in the one-trick poney, i’d rather suggest that it sends a NoteOff message when pressed again. It’s more practical using the ARP or SEQ setting than the ARP+lt or SEQ+lt.
    Or, we can leave the option up to the user…

  • Or you can choose at startup between these Programs

    • Note On/Off like a 1Key Masterkeyboard + Pot for NoteNumber
    • Latched + Pot for Notenumber (turn the Knob while latched and it sends a NoteOff for the old and NoteOn for the new Note)
    • Chords (plays arpegiated Chords, latched, Pot scans thru different chords: C, Cm, Csus2, Cmaj7, C7/9 etc….)

  • Then you’ll have to rename this to the 3TricksPony™

  • Hmmm, this poney is starting to learn too many tricks :)

  • nice :) i am sure this would fit inside the shruthi case, if build very tiny.
    i am just not sure, if the controls would fit. ...button, pot + it would need an extra switch to be able to detatch it from the midi in.

  • Maybe something based on a tiny accelerometer? Is my shruthi broken? (shake it… test tone) No it’s not!

  • in my opinion, if you want to fit it into a shruthi case, you better use directly the IN1 to IN4 ports?

  • WOOT!

  • @loderbast
    You can go without the Pot if you like, then you only have one Key….

    Just checked, i can disconnect the HardwareSerial In Port so i have another free I/O Pin. Lets give the accelerometer a try….

  • Just fit a piezo transducer in the case. Tap the box to play a sound :)

  • naah, you cant sell this to the bay area or japan….

  • “photoshopped one trick pony logo with an infinity sign instead of a one”
    “photoshopped one trick pony logo with 1111 instead of a one” + “it’s the 15 tricks pony (in binary)”

  • i could use the spare pin for a serial lcd…

  • or perhaps some 7-segment displays for note number readout?

  • Frank, you’re the man!

  • Thanks schrab; 1 Key seemed to be within my reach ;-)

  • @ fcd72

    I need something almost exactly like this, but instead has a center detented pitch wheel and a midi thru or combiner or something. Basically to add a pitch wheel to a non-pitch wheel having midi keyboard. Chain the two together and boom, easy fix. How hard would it be to modify the code to do this? And how hard would it be to add a midi in + merge?

  • @n8bit

    “I need something almost exactly like this” – but indeed totally different. The only thing in common would be that both need 5V Vcc ;-)

    For the PicAxe Series of Chips you would have to

    • use an external A/D for 14Bit accuracy or at least significant more than the 8 Bits the PicAxe provides, probably connected via i2c that collides a bit with the Hardware Serial Out used for MIDI – there is only 1 UART. I have never tried the 10 bit input command (readadc10) for using enhanced internal resolution so i can’t really tell about if that works or not.
    • adding a useful internal MIDI Merge is not that easy as it would not only to pass thru bytes, it has to keep track of the running status so you don’t scramble up Data when merging your PitchBend Whee Data and it has to do useful SysEx forwarding…but its doable (i know because i did it ;-) )
    • add a 6n137 for the MIDI in + some Rs Diodes, Caps, a Proper PSU – so it grows to a real Project…

    Using a 20X2 or bigger chip will probably do, but – I’m hopefully not to rude saying this now -please don’t ask me for doing this. Instead get y PicAxe Development Kit yourselves, ill gladly share my MIDI related Code. Or just buy a DOEPFER Wheel Electronic + Wheels.

  • And “ something almost exactly like this “ but whith 7 micro switch ( A B C, Do Ré Mi ) Instead of potentiometer ? it is also totally different ?

  • No, it’s not much different. With a resistor network you can replace the potentiometer by a series of switches. When you detect a certain value on this input, you know that some switch has been pressed.

  • In the world of demanding people who always want a few more features more I reckon this will end up being a 47 key controller with knobs on :)

  • @Lucchio
    Only More keys or with MIDIthru?

    For more keys and MIDI thru i’d take a 20x2….

    If you have more ideas I might be tempted to do a MultiTrickPony Development PCB, just like the Shruthi-1 Playground PCB. It would include the MIDI Jacks + Optocoupler, a PSU, a PicAxe 20x2 Socket + Download Circiutry and a PerfBoard area on 100x75 PCB. Add PicAxe USB Cable and then yue can build your own M-TrickPony to your like.

    Anyone seriously interested?

  • Not “midi thru” just change the pitch with buttons instead of a potentiometer.
    The MultiTrickPony Development PCB is a good idea but in my case I should learn how to use the picaxe ! :)
    The goog thing is there is no danger of damaging the instrument by playing with the M-TrickPony PCB ..

  • @lucchio: pixace is really simple to learn. in fact the main advantage of those chips is that they are so simple to programm.

  • @loderbast : I put this on top of my list: “thing to do” !

  • @luchio
    Why don’t you give it just a try, a 08M2 Starter Kit is just 17 GBP, maybe add a 20X2 und you are halfway in DIY-Controllerland ;-)

    edited to 6581s sharp eyes

  • You mean 08M2?

  • Update:

    The One Trick Pony slowly evolves: currently fellow ShruthIzen™ loderbast and me are discussing makin a OneTrickPony™ PlayGround PCB, that houses a PicAxe 28x2 @ 64MHz, MIDI In & Out Jack + Optocoupler, a 7805 based PSU, a LED and the needed Download Circuit for the PicAxe System Programming Cable. The rest of the PCB has just a long double row of 3xPADs suitable for installing small DIP ICs and a big PerfBoard Area. As the Board has the Shruthi Form Factor Generic Cases would be available.
    Also provided would be Sample Code for a rock solid low latency Software MIDI Thru, Code for dispatching CCs and Switching 4053s, Code to make a simple 4Pot MIDI Controller and some other surprises.
    Target is anyone who wants to do something you can plug into an MIDI device easily (the PicAxe Basic is dead easy to learn, the development Environment is free, a Download Cable is just 15€) that does one thing that others don’t do – hence the Name OneTrickPony.

    So let us know what you think….

  • It is an interesting concept. It really depends on its potential. I don’t assume we’ll be using it to make new digital effects but perhaps new controller apperati?

  • I have a bunch of Ideas for Controller:

    • Ribbon Contoller
    • alternative Keyboard Layouts
    • Program Change Send Thingie for Live Setups
    • Start/Stop/Rewind/FastForward/Record for your favorite DAW (including Song Position Pointer…)
    • Motion Controller via 3axis Accelerometers

  • i’d love an alternative keyboard layout! there’s some really interesting development going on with ipad apps for that.
    like soundprism
    would be great to have something like that incarnate in a real controller

  • Some sort of MIDI lego would be fun. Build a UI using blocks with switches etc.

  • Incidentally, I was thinking that a tiny 1 octave keyboard in 303-shape would be the perfect companion for the anushri. Ok, that’s a standard looking, boring keyboard, but still it has proven to be pretty efficient, eh?
    But anyway, my plan was to base it on one of the buggy_at_20Mhz™ ATMega chips Olivier has provided me, so I’ll follow closely this thread, while probably developing something relatively similar in parallel…

    Edit : oh, and to communicate with the chip (for all your needs for blinkenlights and buttons), this might interest you : I’ve ordered samples of PCF8574A and TLC5940 chips – available as free sample in DIP package at TIs….

  • i’ve been using the anushri with the korg nanokeys. It’s a perfect companion with the switches for pitch and modulation to program the sequencer.
    Would be nice to hack this keyboard with real midi.

  • This makes me think of another thing… what happened to the Octopot?

  • The One Trick Pony is kind of a stripped down Spin off of theOctoPot – i upgraded the OctoPot to the Big 40x2 Chip to integrate the Display handling into one Chip for Timing reasons as i want to get this thing as transparent as possible for MIDI thru. I also added some eEprom Memory and have 2 additional useful applications in development. Alltogether this takes a bit more effort than thought but I’m at it.

  • great, because you know… I’m still waiting for it :D
    But don’t feel pressed. No no… I can wait. I mean your avatar reminds me of it every day, but I can take it, I’ve learned to live with it.

  • @rumpelfilter
    I won’t release anything before it meets my own standards – but you are one of the pitty BetaTesters to be tormented

  • you need betatesters….(pleads)

    edit: and is pathetic)

  • 4x4 button matrix support will be great!

    200 x 176 - 1K
  • @schrab
    There are plenty of unused I/Os so no Problem – Cool Logo!

  • 1 pot 2 encoders and 16 buttons to be exact.

  • @i’ve been using the anushri with the korg nanokeys. It’s a perfect companion with the switches for pitch and modulation to program the sequencer. Would be nice to hack this keyboard with real midi.@
    Absolutely, the nanokeys looks great. But the USB-only thing is really pissing me off. I know there are solutions for this but they are quite expensive, and you quite lose the advantage of a compact setup because you multiply elements of gear..
    That’s why I’m thinking about something DIY with a cool “shift” button that allows you to program some CC controls for each key. A lot of dev time, not so cheap, but anyway. I want to learn. And it seems to correspond to schrab’s need actually, only in a different shape.

  • All these things you could easily Achieve with the OneTrickPony. If you want to take a look, take a peek on the PicAxe Website and grab the Manuals Its really easy to Program, the 28x2 @ 64MHz is powerful enough to do all your scanning and MIDI Processing

  • Yeah I know about the PicAxe, and I really know that our intentions are actually very equivalent, we’ll probably end up with about the same hardware. I just don’t want to mess up with a new development environment. I’ve got a lot of things AVR, I’ve received today a TI MSP430 Launchpad (it costs $4.30 shipping included btw…), I’ve got a PIC programmer that I never used, a freshly received lpc17, an arduino mega… I’m soon to receive a TI ARM-based launchpad and a raspberry pi…
    Actually, as I stated before, I’m going to be unemployed starting from November. I don’t know how long it will last, but I’m taking the opportunity of really trying to learn how to program on embedded systems, assuming it will be of some value on my computer scientist CV. And of some value for my musician gear, of course ;)
    I’m afraid the PicAxe has a “toyish” connotation (well, undoubtedly an Arduino also), and for this purpose I better develop things from A to Z.

    By the way, why wouldn’t you directly get the corresponding Pic chip? The picaxe is easier to program and get started with, but you’re basically paying for a pic chip + a bootloader, which I think becomes quite useless once you’ve acquired more experience..? I suppose that your intention is to develop a kit, but what’s the advantage of chosing a picaxe over a plain pic µC for this perspective?

  • Ooh, I lurvs me teh smell of a beta test! Could threaten to send some pictures of tits if I’m excluded… Gotta stop those weekend daydreams.

  • @MicMicMan
    The development Environment is free, you only need this cheap Cable. The reason for not using a normal Pic is that the learning Curve with the PicAxe is very steep, i think with an appropriate Tutorial everybody that sometime in his life has learned just a bit about programming can do a MIDI Controller. First learning C(+, ++, -, &%/ or whatever flavor) is a bit more tedious task and will shy many more people away.
    The additional Cost for the Bootloader and the PicAxed Chip are in relation to the time you’d need to learn how to program a PIC Chip from scratch marginal. How long do you work to earn 3€? See? ;-) So one objective here is not to do State of the Art programming and squeezing the most out of a chip – its about the fun you can have building a dedicated Controller for some of your gear in just one evening.

  • Well, the 3€ are to multiply by the number of projects. Sure for a small and cool personal project every once in a while it’s not important, especially if you want to develop it quickly.
    It’s not the same story when you plan launching a kit batch of 100+ units, however.

    I might have been misunderstood – In no way I want to criticize your choice, that’s really a great idea you have here. It’s a cool way of having members of this community to get initiated to programming embedded stuff. Olivier’s stuff was also thought this way, but Olivier’s code is pretty intimidating due to a lot of (necessary) sophistication. I just wanted to know your intentions, and have a bit more insight.

    edit : oh, by the way, I know it’s possible to DIY a programmer for picaxes using a simple audio cable – you might consider adding this audio-plug to your pcbs, so people interested in modding this thing aren’t even required to buy a programmer. I bet everybody interested in this project owns a soundcard :D

  • The Download Circuit will be included (its just 3 Rs and a 3,5mm stereo socket) for shure. How people connect it to their computer is up to the individual – i certainly would not recommend it with a Soundcard due to the upcoming Support Hell ;-)

    Shure its a total waste of computing power using a PicAxe at 64 MHz to achieve something you could do with the same PIC programmed at machine Level at 4MHz but the last is Expert Level and thats not what i am aiming to – I’m self confident enough to know ill never could compete with MIDIbox ;-)

    Its really meant as a Platform for your personal one off “My Coffee Machine runs on Channel 16 and accepts Note 64 ON/Off for making coffee” Controller
    EDIT thinking of it it could report level and temperature of the coffee back via CCs ;-)

  • I’m not criticizing a waste of power at all, if 64 Mhz is as cheap and as reliable as 4 Mhz then why would you ever think about going 4 Mhz?! :)

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