Author Archives: Damien Gardner - Page 3

Trial run of the full 48 Relays

Starting to feel the pain of how much wiring there is just in the Relay Driver board.  Wishing I’d had the forethought to simply get a Board printed up in china 🙂P3290758P3290759

Dismantled an ATX extender to get myself an ATX socket to power the relays from 🙂 The wire seems a little thing.. But if it’ll power a motherboard with multiple PCI cards etc, it should be fine?


Started cutting the Ribbon cable for the Pi power cables.  Man, there is going to be SO much of this!


Power inputs for the Relay boards.  So much wiring!


And for some fun – here’s a full on, reboot, off test of all 48 relays!

Modifying the Relay boards

I had to modify the Relay boards – The relays were getting VERY hot.  Turned out to be a fault in the design – the 5V relays were being run from the 12V supply.  Simple fix to cut a trace, and run a wire to the output of the on-board 5V supply.  I guess that explains why they were $6 a board 🙂


And a quick look at the half-finished Relay driver board!  That’s 6 x 74HC255’s and 6x 74HC244’sIMG_3054

Almost finished the first bit of Fabrication

And another temporary workbench 🙂


Today we’re building the mounting frame for the Pi’s, ready to go in the case.P3220722IMG_3043

See where I’m going with this? 🙂  I reckon I can fit 48 Pi’s in a 2RU chassis.  That’s not bad 🙂


And time to test the frame IN the chassis.  And then start assembling it all!



And now we get to see the whole thing together!

P3220737P3220738You have to admit.. That is pretty sexy!


Starting the Fabrication

Today I did just a bit of fabrication 🙂

Fab work is always ‘interesting’, given the garage is full, so all work gets done out in the carport.  Which means lugging whatever tools I need outside as I need them.  Today we’re cutting up the Pi carriers, as well as starting on the framework that the Pi’s will actually sit in.


The carriers worked out pretty well.  Looks like I’ll get three rows of Pi’s in the case!  NICE.


And then starting on the framing.  More on that next weekend!P3150705

Mounting fun

Started work on mounting the Pi’s.  Biggest hassle was working out how to supply power, in a way that still makes them nice and modular incase I have a dead pi once it’s sitting in the DC.  Can’t very well power off 40 Pi’s to replace one..


I had considered using a bunch of RC power connectors to plug the carrier boards for the Pi’s in. But it ended up being FAR too difficult.   Decided to go with the tried and true method of a power cable 😉  It’s going to mean a LOT of ribbon cable though!


Tomorrow, I hope to have the whole carrier framing sorted!