Current Status as of 6 November 2012

I’ve made the move from breadboard to a prototype printed-circuit board.  This attaches the microcontroller, the SD card adapter, the real-time clock, and the serial level adapter onto a single board.  Here it is in action:

The small green board on the left side is a Teensy 2.0 from PJRC with its matching SD card adapter piggy-backed onto it.  The remaining circuitry handles the real-time clock (which is needed to convert the downloaded data into usable form) and the serial level converter.

I’ve had difficulty with the power supply on this board, and at least part of the problem is that the MAX1674 IC I’ve chosen is just too small for me to hand-solder.  I’m working on a revision of the board that will, among other things, replace it with a device (the NCP1402) which will be easier to solder.  This prototype works just fine from a USB charger, but does not work as intended from two AA batteries.

The Teensy is an Arduino-compatible microcontroller, making it relatively easy to program and interface to the outside world.

I have my source code in what seems to be a working state at this time, though it has not been extensively tested.  More accurately, it’s completed one download from my UBG-16 without apparent errors.  Check out the other software requirements before attempting to use the source code.

This project has progressed significantly.  Schematics and board layouts can be found on the Hardware page, as can a link to the parts list.  Bare circuit boards are also available for $5.00 each, shipped; contact me by e-mail if interested.  I also have some documentation on the EI downloaded data format.