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(Last updated: Saturday February 24, 2007)

mTW523 - the modified TW523 project

Sorry still under construction

The programs under this project are Licensed under the GPL Open Source License.

I've quickly thrown together a page containing the various parts of the modified TW523 (aka mTW523). It's going to take me a while to piece together the instructions on how to build this beast. So for now here are the parts. I still need to build a schematic for the mTW523 to PIC and PIC to RS232. I'll be using gEDA to produce the schematics but I'll also output them as .png files.

I'm interested in comments and suggestions on improving the device. I really don't want to hear that it's a peice of garbage (I already know that but it's a better peice of garbage than is currently available). One of the things I am working on is switching the PIC16F87x to a PIC12C67x. This should make the board easier to build. I may also include PCB files from one of the cheap PCB houses so the boards can be purchased and built by various people. I have no intentions of providing kits (sorry) but I wouldn't mind someone else doing it (just remmeber to give credit where credit is due). The other improvement is to take advantage of the ADC on the chips and measure the actual amplitude of the signal (Thanks to Dave Houston for giving me the idea on how to resolve the protocl output). That's a later project but an interesting one.

Please note that all the code files found on these pages are currently in poor shape. The device was meant as a tool for other projects but I thought I might as well share it. I will clean up various sections (such as the while loop in the Perl code, that was a quick kludge and really needs cleaning up).

  • Modified TW523 - another version of this page with a bit more info on the entire project.
  • SD523 - another version of this page with a bit more info on the entire project.
  • X10 sniffer - another version of this page with a bit more info on the entire project.
  • - My Perl Program to interface between Linux and the PIC connected to the mTW523. It currently uses the Curses and Select modules so I don't know if it's portable. I'm currently working on a Perl/TK version which should be portable (at least between Unix and Windows).
  • x10sniffer.c - The C code for use in the PIC16F87X chip. It was compiled with the C2C compiler. This compiler has some real odities so you'll probably notice a few wierd sections of code. I just can't remember why I did what I did (SMACK, bad programmer, that's what comments are for!).
  • x10.h - The header file used by x10sniffer.c.
  • X10SNIF.ASM - The Assembly language file used by Microchip's MPLAB
  • X10SNIF.LST - The .LST (list) file produced by Microchip's MPLAB.
  • X10SNIF.HEX - The HEX file produced and used by Microchip's MPLAB
  • mTW523.scm - gEDA schematic file for mTW523.
  • C2C C compiler for Linux, DOS, and Windows

  • You may email me at