Anyone seen my Red Pitaya? Is that it, under there?

red pitaya shield1

The "shield" is a new PCB that sits on top of the Red Pitaya. It replaces the original hand-wired Arduino shield, and acts as an interface to a number of other things:

Most of the board worked straightaway... except for the Codec board. the Codec, it seems, doesn't "like" the 3.3v to 5v level translator chip between the Red Pitaya and the Arduino.. I've not understood what it's not happy about - the logic levels look fine, and the timing is essentially identical - but with the level converter powered, the Codec won't respond to I2C commands. In the short term I've removed it and bypassed the level converter, but I'm not totally happy with that arrangement - it means the Arduino is only getting logic 1 voltages of 3.3v which marginally meets the specification. i'd be a lot happier with a "proper" logic 1 level. 

red pitaya shield2

I've included space and mountings for a fan, but I don't think it will be needed.

 

Next stop - the Munin amplifier. I have most of the components now - just need to get on and make it.