Computing stuff tied to the physical world

JeeNode in a bottle

In AVR, Hardware on May 3, 2009 at 00:01

When you have a hammer, everything looks like a nail. Or in my case, a potential enclosure for JeeNodes:

JeeNode in a bottle

This adjustable enclosure came with some small relays shipped to me a while back.

Now if only I could figure out a way to make JeeNodes run a while on these batteries:

3.7 V @ 100 mAh Lithium

That’s a 3.7 V @ 100 mAh Lithium cell. Three months endurance would be the minimum needed to make this practical, that’s about 40 µA average power draw (the RFM12B draws 30 µA in sleep mode, though that could be lowered tenfold by connecting it to a switchable regulator such as the LP3985). Hm, might actually be feasible.

  1. Where do you have that 30µA value from? I just checked the data sheets, and the RFM12(B)’s supply current in sleep mode is specified as 0.3µA.

    But even if powering down the module externally is needed, you could save the regulator and just use a spare port pin to power the module. The ATmega168’s port pins are specified to drive up to 40mA and the RFM12B’s maximum supply current when sending at 868MHz is 25mA.

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