Hello,
How did you decide to go with 3.3v, rather than 5v, when you designed the JeeNode?
Thanks,
digitalhack
3.3v vs 5v
(7 posts) (6 voices)-
Posted 12/10/2009 01:31:53
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Simple - 1), the RFM12B doesn't run @ 5V, 2) some newer chips can't tolerate 5V either, and 3) many interfaces run fine @ 3.3V.
Posted 12/10/2009 07:43:21 -
It ist possible to run the Jeenode with 5V. Don´t solder the voltage regulator and buy an RFM12 5V version at the pollin.de shop.
Posted 13/10/2009 22:35:19 -
The choice of 3.3V is one of the reasons that attracted me to this design. A 3.3V is much more elegant and seems more inline with the "real" hardware industry.
Posted 16/10/2009 03:48:18 -
With 1 AA cell and this: NCP1400 3.3V you don't waste any power!
Posted 18/11/2009 15:31:49 -
I was reading about a "joule-thief" the other day http://tinyurl.com/yeluun3 which seems to be a home-made version of the NCP1400; don't know whether it's smooth enough though. Interestingly, there's a version driven by a peltier and waste heat from a toaster.
Posted 01/01/2010 14:57:14 -
Google for "joule thief efficiency" for more info about that approach. I'd expect the NCP1400 to work better, because it generates regulated output, whereas with a JT you'd have to regulate (i.e. throw away) any surplus voltage.
A single AA might be pushing things a bit IMO. I'm considering setting up a piggy-back unit for JeeNodes with an MCP1257 and 2 AA's. It only draws 10 µA in "sleep" mode, and one I/O pin can switch it to normal mode to provide more power during RFM12B activity. Needs only 4 ceramic caps, no inductors.
Posted 04/01/2010 00:05:03