Thursday, June 4, 2009

Lessons learned 2

This is how the board looks after it was populated.

The main reason for the hack was to install a connector to Tx/Rx pins of the microcontroller. So, always wire Rx/Tx pins of the microcontroller to an external connector (e.g. FTDI) that you can use for serial communication. Otherwise, your software issue (sketch fix/upgrade) becomes hardware.

(to be continued)


  1. I just made a similar mod to the board you sent me! I drilled 4 small holes and epoxied in a 4 pin sip for +, gnd, Rx, & Tx. (I use an LED on the Rx line to tell me when to press reset so that's all I need.) I assume the transistor you have is to reset automatically? I can now load the board directly which is nice at my current stage in development!

  2. The transistor is supposed to drive the reset line to ground, based on a signal from XBee. There are 2 documented methods that I know: one described by Rob Faludi (output pin from atmega drives the reset, "rejected" by ATMEL), the other described by ladyada (pin D3 from XBee drives atmega's reset). I will write some conclusions later, since I am working on the second method (first one did not work for me).