Nora - Design docs?

Any update on when we might see the Nora boost supply design?
I’ve been running most of imps off 2x AA Energizer Lithium for a good three months working well often down to 2.2v :slight_smile:

It’s coming very soon. We’re running a lot of cycles on a nora2 right now checking this out with different battery types :slight_smile:

Thanks we should have a “Hugo soon scale” :slight_smile:

Hugo by chance does the Nora2 have circuitry to charge batteries? that would really “Blow the bloody doors off”

Thanks

It doesn’t, no… if you were making a rechargeable version you’d likely go with a Li-Ion pack vs a couple of AA NiMHs though.

if you’re using NiMHs, a charging circuit becomes really simple: you can charge them at 1/20’th of their rated capacity. so if you have 2000mA/h cells, you can charge them with 100mA.
A LM317 with a single resistor makes a nice one. Like this: http://theparanoidtroll.com/electronics/primers-and-tutorials/other/constant-current-sourceload-lm317/

For 100mA you would use a 12.5 Ohm resistor.
Imput voltage needs to be about 3V + (1.45 * number of cells).

Hugo & remcohn thanks I will take a look I’m porting a self powered soil moisture sensor I’ve had running via a set of solar panels and a handful of supper caps to the imp.

http://dx.com/p/mini-usb-1a-lithium-battery-charging-board-charger-144856