Sunday, August 2, 2009

Jaluino Medium 18F2550-based: first draft

Jaluino, with user guide, schematics, PCB, shields, etc... can now be reached on the following sites:

Main site:

Careful, schematic and PCB in this post aren't tested yet. Except if you're a daring risk-taker, you shouldn't build this board as it would only be a waste of time, and probably of money too... You've been warned.

I'm still on this Jaluino board.

While trying to get a working schematic, I've also spend a lot of time drawing the PCB. I focused on a 18F2550 version, instead of big fat 18F4550, so PCB layout is simpler and I can focus more important issues for now. So this is now about Jaluino Medium (18F2550), not Jaluino Maxi (18F4550). BTW any ideas about "marketing" names to replace Mini, Medium and Maxi ?...

Last schematic contained lots of errors, mostly on USB and dual power. Luckily Guru Albert helped and provided me four options. I kept the simpler one (I can understand), which consists in having a jumper to select whether power should come from:
  • external supply (jack)
  • USB self-powered connector
(I would even add a new source of power: from serial, and more specifically from a USB-to-serial converter)

The current schematic seems to look better (yet still untested, this will be for other posts).

So here how the PCB looks like now...

This PCB is expected to be 8.1cm x 7.1cm (3.2in x 2.81in). Compared to an original Arduino (6.9cm x 5.4cm), it's a little bit bigger. But it's also a single side board, and there are lots of other connectors (I²C and serial) not present in Arduino.

There are several connectors. Some will be the shield connectors (JP1, JP2, JP4, JP5 and POWER), female headers as in Arduino, others (ICSP/JP6, I²C, serial) will be male headers.

The shield is expected to be something like 4.8cm x 5.8cm (1.9in x 2.3in). Original Arduino's shield is 4.9cm x 4.3cm. It's a little bit bigger, and I may adjust connectors (move JP1 & JP2 lower) to have a "more squared shape".

Next posts will be about testing and prototyping this board, using a breadboard. This will also be a good exercise to have basic (and maybe advanced) experiments using jalv2 and jallib.

S├ębastien Lelong


  1. I think serial connector and power connector must be in line with the others...

  2. Easy to make the shield? Or looking less complicated? Easy to insert and remove a shield? Closer to Arduino (not too much differences)?

  3. Hi Seb,

    Looks like C2 is wired wrong in the scematic. Better check that. B.t.w. I would love to see a JalduPilot someday.


  4. Hi,

    This is post is getting outdated, Jaluino is now available based on 18F4550 (18F2550 will someday come). Check Google Code project "Jaluino", explore sources for mainboard & shields schematics:

    Documentation will soon be available on website


    PS: yeah I'd love to see a "jalupilot" board too :)