(check the comments, I’m posting updates down there)

Touch Arc is a Monome Arc emulator for development purposes. It is very much not intended to be “nice” to use or a competitor to the hardware, so please don’t complain about that aspect (if you want a useable and ergonomic interface that’s a joy to use, buy an Arc).

Touch Arc comprises two parts, a TouchOSC template and a Max patch that works as the middle ware and converts the Arc OSC your app is transmitting into a format the touchosc template can interpret, and vica versa it takes the touchosc template interface input and converts it into fake Arc OSC format that your app can handle.

This way developers can work on proof of concept, sound in the knowledge that once the arc hardware is released their applications will function.

The touchOSC template initially replicates all the in and out points of the Arc 2 (I’ll do an Arc 4 one later if there is a demand).

This means there are two duplicated UI’s for each encoder, these are made up of:

- 64 slider ui elements, which can handle values of 0 – 15 (these are the LED’s)
- 4 momentary buttons, that output every 100ms either -2, -1, +1, +2 (these are the encoder turns).
- 1 momentary button that registers as an encoder press event.

For the LED side of things, due to the limitations in the TouchOSC interface, the LED UI is made up of 4 multisliders each made up of 16 subsliders. We could have used 64 single sliders, but they can’t go narrow enough to get 64 of them in a row, even in landscape mode, this means the LED handling middleware needs to do a fair amount of math converting 0-64 into 0-3 + 0-15 coordinates. For this reason (and mainly due to hitting a brick wall with the range wrapping round at 64, I used Javascript as the main math function handling.

The interaction conversion side of things is a much easier straight translation, so I handled that with just Max. The encoder rotation interface is faked by firing a value every 100ms for as long as one of the valued buttons is pressed in the UI. I could replace these with a slider the more you slide it from the center the faster it fires the +1 or -1 values, but i figured for ease and simplicity this approach worked.

Source code is available on google projects, so you can download it and try it out http://code.google.com/p/touch-arc/source/browse/#svn%2Ftrunk. If you can find bugs or better ways of approaching the problem, I’m very happy to update the code, or please feel free to use SVN and update the code or post other examples directly to the project.

I have spoken to Brian at Monome and he’s very happy for me to make this available, if it makes developers lives a little easier pre launch, hopefully that will be of benefit to everyone.

Update:

I’m working on a native Max UI, to see if that renders better without so many hicups. It could also be used in app patches where you’d like an onscreen representation of the Arc UI. Should be ready for testing very soon.

For a long time I have been toying with the idea of creating a Control Voltage tuned Radio that I can DIY and add to my Eurorack Modular Synth setup.

There are a ton of uses I can see in having easy access to the radio waves: random noise, strange sounds, fuzz and white noise.

But being able to control the tuning with CV so I can jump around the dial, or slew my way from one spot to another I think would be really awesome.  If for no other reason than I like the idea of programming up a sequence and then every time it runs it will be different since the sound source is constantly evolving and changing.

So research began by looking at how radios work, and things didn’t look good to start off.  It seems that radio tuning is all about capacitance, not voltage.

The simplest tuner consists of an inductor and capacitor connected in parallel. The capacitor is usually made to be variable (although the inductor can made variable it requires a more complex mechanism and is rarely used). This creates a resonant circuit which responds to an alternating current of one frequency

http://en.wikipedia.org/wiki/Tuner_(radio)

This means “most” of the time the tuning pot is not a pot but a variable capacitor type thing, which means you can’t just swap out the pot with a CV source (which was my initial hope, ignorance is bliss).

All seemed at a lose until I found out that some radios use what is called “varactor diode tuning” this is a diode that in essence replaces the capacitor bit, but the neat bit about the diode is that it’s voltage controlled.  This means that the tuning pot will be handling voltage and suddenly we have somewhere we can bolt our CV into.

The next snippet of info, was that Ramsey (the makers of great electronics DIY kits) make a series of kits that all use Varactor Diode Tuning, include a $40 FM receiver kit.

So later part of 2010 I ordered one up, and it sat on a shelf for a few months whilst I tried to finish off other “higher priority” projects.

Then NAMM 2011 came around, and I was intrigued to see that Buchla, the makers of VERY high end modular synths was showcasing a new module the 272e which had 4 FM receivers that could all be referenced via CV.  Now their concept is very different to mine, they have digital tuners that you tune and they then allow you to control the outage from each using complex envelopes, there is no CV control of the tuning – that said they do look really very nice indeed.

Buchla patch Model 272e through the 296e Spectral Processor. from Richard Devine on Vimeo.

But if nothing else it spurred me back into life.  So earlier this week I soldered up the Ramsey kit.

With some awesome help over on the muffwiggler forums (MANY THANKS DAVERJ!)

I tapped into a couple of places on the PCB and hooked it up to a very low frequency Oscillator I had running a sine wave, and low and behold I had CV controlled tuning.

Now the tricky bit.  I doesn’t work great. It doesn’t work with CV only with the Oscillator, so it needs a stack load more tweaking and testing.  But my hope is in the next week to get it hooked up to Silent Way and have a fulling CV tunable radio incorporated into my modular synth.