Computing stuff tied to the physical world


JeeHub physical layout

In Hardware on Mar 11, 2009 at 00:01

I’m going to try and fit all the components of the prototype JeeHub onto an 8.5 x 11.5 cm board to match a little enclosure that’s been lying around here:

Picture 1.png

It looks like everything fits – though it’s a bit tight:

JeeHub proto

There are two subsystems: the MMnet1001 Linux module and the rest, based on a JeeNode. The “rest” is actually the core of the system since it will run day-in day-out, whereas Linux could be shut down when no ethernet access or fancy reporting is needed.

The remaining components on this set-up are:

  • a DCF77 receiver for accurate time tracking
  • a BMP085 barometric pressure sensor
  • a 433 MHz OOK receiver to pick up remote control commands
  • a 8 Mbit dataflash memory as piggy-back on the JeeNode
  • a status LED

Furthermore, the RFM12B wireless on the JeeNode can control standard 433 & 868 MHz radio-frequency units such as power switches.

Everything can be powered from a USB port or a 5..6V DC wall plug. The automatic battery back-up allows running the JeeNode core off-the-grid. It’s not a priority but I want to see to what extent a JeeHub can function on its own power. The Linux module will be powered by a 5 -> 3.3V regulator, with a shutdown-pin controlled from the JeeNode.

Much of the basic software for the JeeNode core has already been written. But that’s of course just the tip of this “home-monitoring and -control” iceberg…