raspberry pi2 test-bed (fancy psu stuff)

[linux-works]

wanted to play around with the pi2 board and so I threw together a test bed to let me tinker around.



I'm using a spare copy of a chassis I designed for another pi project.

the modules are:

top-left: a low voltage UPS module that gives fast fail-over from one dc-in to another. normal use will have 18vdc on one jack and a battery at 12v on the other. when 18v is present, it charges the batt and drives the output of the module. when absent, power from the module comes from the batteryl

lower-left: dc/dc converter. I can get either 18v or 12v out of the UPS module; but the pi wants 5v. so, this module does that efficiently and without any appreciable heat.

middle: simple $5 ebay 2 wire voltmeter. its nice to monitor the dc line voltage on test beds.

bottom-right: neat little sd-card (or micro) extender. lets me do a right-angle turn and with the side of the box on, the card hangs out an open slot and I can swap out its o/s 'disk' whenever I want.

upper-right: the pi2, of course.

almost all came from amazon.  parts, for those who care:

UPS module: http://www.amazon.com/gp/product/B005TWE4Q0/
dc/dc: http://www.amazon.com/gp/product/B00MEFJXM0
2 wire voltmeter: http://www.amazon.com/Digital-Voltmeter-3-00~30V-Motorcycle-Battery/dp/B00R5YAM5C
sd card remoter: http://www.amazon.com/gp/product/B00L9OB7WQ
rpi2: http://www.amazon.com/Raspberry-Pi-Model-Project-Board/dp/B00T2U7R7I

power for the pi has always been a problem, of sorts, so I kind of oversolved it, to some degree, I guess   I'm putting 5v directly onto the board and bypassing the usb connector.

before I did this, I did try the board standalone with a usb micro cable.  I saw the power led blink on and off during some heavy loading, so there are still some issues with the onboard psu and relying in usb power from a computer or wallwart.

anyway, there's my test bed and parts list in case anyone likes the idea and wants to replicate it.  the UPS module works well if you have a 12v sla battery on one pair of wires and an 18v laptop brick supplying power to the other pair.  I might see if I can find a small enough 12v battery so that it can sit right inside this chassis.