Thursday, 4 October 2012

Tiny TV

I lashed up a teeny TV driven by the composite output to see how it would look. It's not the easiest thing to use (!), but it does mean that I can now build a teeny, tiny self-contained Piana with its own display.

The TV is USB bus-powered (or it is now, after I took it to bits and attacked it with a hot soldering iron), so I now just plug a USB into my MIDI breakout board to power both this and the Pi, the Pi is powered by 5V on the GPIO header. Cool! And it was only £15.

Also - this Piana is running 8 note polyphonic, with the filter in place. I need to benchmark the new modulation code, and double-check my overclock settings (I think I'm at 900) but it looks like I've saved enough cycles for 8 note polyphony to be reliable. 


  1. > And it was only £15.

    From where?

  2. The power of Google will help you. But heck, I'll help you anyway - eBay .. hang on, need to check my email ...

    Here's the item on the vendor's shop -

    and I did the 'cut out the 12V regulator' mod that was mentioned here - - I tapped straight onto a 5V point on the PCB rather than onto a capacitor leg, otherwise the same trick.

    Note that you'll need a USB PSU with much grunt to power the telly and the Pi - I'm using an iPad 10W adapter.

    1. [For some reason blogger now insists on making me anonymous but its still me, I'm just failing to use the OpenID that worked yesterday]

      Wow. Thanks. The blog post link is especially useful...

  3. Update on the clock, I was actually at 1GHz when I filmed this with maximum overclock and overvolt, at 900 it's still fine most of the time, but I see the odd audio dropout so need to get tweaking.

  4. I just bought one of those screens. I can't believe you can buy a 640x480 screen for £15 now. Utterly amazing.
    You must try to get the midi ports working....this whole thing now is too much not to see it all in a box with some midi ports!

  5. The MIDI works fine, I just have to hand-solder the damn boards! I'm not going to enable USB MIDI on this thing, it kills performance and it means if I use a real 'old fashioned' MIDI interface then inexpensive non class-compliant keyboards can be used - so I could use for example an entry-level but perfectly capable Oxygen 49 or Oxygen 25, rather than the much more expensive Axiom range. I want this to be an affordable option.

  6. Oh ok I wasn't sure how the midi was at the moment. Oxygen 25
    S are cheap. I own one....they are selling for tuppence on eBay. I've also got a zoom fx processor that was 25 quid. If I build one of your synths I'll hook it up.
    Maybe you should build another one and send it to Wendy Carlos. Switched on Piana!