Computing stuff tied to the physical world

Lithium node

In Hardware on Jan 23, 2010 at 00:01

The 3.6 long-life / low-current OmniCel lithium batteries just came in.

Say hello to the latest room node at Jee Labs:


Colorful, eh? ;)

The battery is connected directly to +3V and GND, i.e. after the voltage regulator, since its operating voltage is an excellent match for the ATmega and RFM12B.

No motion sensor was needed for where this node is going (and I didn’t have any left anyway), so that reduces the current draw by some 40 µA. Average should be somewhere around 200 µA – as mentioned before, this can no doubt be optimized further.

Since there are no motion triggers, this node will only send one or two packets per minute – the battery should last well into 2011, according to the specs.

Unless the receiver is turned off and this thing starts re-transmitting all the time. I really need to fix that flaw…

For a fun enclosure, check out the Airwick post by Szymon Kobalczyk on the Jee Labs discussion forum.