Thursday, July 10, 2014

bGeigie Nano PCB remixed

As I pointed out in my review on Safecast bGeigie Nano kit, the size of the current software already reached the limit of processor's program memory of 30KB or so. From this point on, it is difficult (if not impossible) to add new code features, and that may require drastic code optimization or even disabling existing features.

I thought that the easiest solution to keep this project up-to-date is by upgrading the processor, by entirely replacing the Fio board with an ATmega 644P plus a few extra components (e.g. LiPo charger). This makes the kit a bit more challenging to build, since it requires soldering SMD components, but could also save a few bucks. The device is still Arduino-compatible and programmable, like to Fio, using the FTDI breakout.

Updated Jul 11, 2014: As Rob suggested, I added the XBee module as well. New Eagle files are here.
This is how the bGeigie Nano Plus PCB looks now. (I also added an option for the Fastrax UP501 module, a bit cheaper then the Ultimate GPS breakout, but still a great GPS module (if you can find it on ebay or other sellers)).


The Eagle files for the upgraded bGeigie Nano can be found here.
On the board, the positioning of the modules, switches, headers etc. is the same (except for the Fio, which is now gone).


A few more points:
  • The LiPo charger follows Fio's schematic, using the exact same components.
  • The ATmega644P processor will require burning the bootloader (board has ICSP header).
  • To compile and upload sketches, the Sanguino core files need to be added to the Arduino IDE (as detailed in this post).
  • ATmega1284P, with double the program memory, could be used instead of the 644P, since it has the exact same footprint (and it is pin compatible).


Unfortunately I am short on cash these days, so I hope someone could order the PCB with oshpark (the set of 3 original PCBs was $52 when I ordered them a while ago) and prove the design. I could help with the IDE setup and probably with some software development as well (the first thing that comes to mind is using the whole 128x64 OLED screen, and not just half).

As always, any feedback is appreciated.

5 comments:

  1. Whoooooo, very nice job. The extra memory would be great. Pity no Xbee on the board. That would be interfacing easier. A BLE 113 or 112 on the board would be a very welcomed addition. Probably also better to market the board as a bGeigieNanoPlus version.

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    1. Thanks.
      I forgot about the bluetooth. I will add one.

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  2. Maybe even considering replacing the ATmega644P with a Teensy 3.1. So people with limited soldering skills can still make it. The advantage of the FIO was that it is easy to assemble..

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  3. I'd avoid 644p and use 1284p instead. It costs virtually the same, but has more RAM and also better bootloader (Sanguino is so buggy). I switched my Xronos clocks to 1284p long time ago, just had too many issues with Sanguino. Also for bigger boards I suggest iTead, you can get ten 10cmx10cm (2 layer) boards for less than $30

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