Computing stuff tied to the physical world

Indoor temperature, etc.

In Hardware, Software on Nov 20, 2010 at 00:01

Here’s a fun little project…

A Graphics Board with a JeeSMD and two plugs: a Pressure Plug and a partially-populated Room Board.

The result is a geeky little indoor environmental monitoring station:

Dsc 2293

Couple of notes here:

  • I took the lazy way out and merely display the info as text, graphics would be so much nicer!
  • Both sensors can read the temperature, but as you can see, they don’t fully agree…
  • I added the FTDI hookup and used it to power this thing via an AA Power Board.
  • The AA board does double duty, as a little stand to hold this thing slanted upwards.

Adding FTDI was very useful in this case, since it also makes it possible to re-program the JeeSMD, which has no FTDI connector on board. All it needs is a 0.1 µF cap and the 6-pin header:

Dsc 2298

But there’s more to it than that, alas: to be able to upload to the JeeSMD, you need to hook up all the headers on the JeeSMD, i.e. also the PSI and the SPI/ISP headers. Adding those after the fact is very tricky, since you can’t reach the back of the Graphics Board pcb anymore if you soldered the LCD on permanently – as I did.

I had to solder the female headers slightly higher, to just barely reach the pins from the top with a very fine soldering iron tip (I use 0.4 mm). It worked, but as a result, the JeeSMD sits a bit higher on its pins than usual:

Dsc 2297

Here’s the indoor.pde sketch, also added to the Ports library:

Screen Shot 2010 11 17 at 22.47.37


  1. Very nice…

    A little trick I discovered with the male headers when I had to solder them from the “wrong” side: If you place them pointing down against a hard surface, you can push the plastic separator bit down the pins with a pair of needle nose pliers, that way you can solder the pins further into the board and then push the plastic back down again.

    • Nice trick – but unfortunately in this case I needed to place female headers (I always use male headers for PSIX and SPI/ISP on the JeeNode).

  2. Ah yes, of course… For those you need a different trick, it involves a sanding disk! (You know me, I’m not joking!).

  3. When do you expect a resupply of Graphics Board Kits to arrive to the shop?

    • I’m trying to get a few more boards + alternate displays before Dec 10. Larger quantities later in December, if all goes as planned.

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