During investigation into a problem with mfx operation I developed an Arduino based sampler program to record and decode the mfx signal from the track - that can be found in this forum under the Marklin Locos - MFX or DCC topic.

As a separate spin off I developed a rather grotesque track powered mfx sniffer sitting on a 4411 chassis to confirm my work. It shows the address of each loco the controller is sending commands to - I chose to also show direction and speed. It can just be placed on the track to report on what is happening - no wiring or connections needed. While the carriage itself is very unlikely to be of any interest to anybody the Arduino program powering it can be used to capture any mfx frame and could easily be the basis of a cheap decoder or custom controller. It works with single and dual MS2s but I have no way to check other systems.

For those wanting to dig deep into the workings of mfx and build something I recommend Stefan Krauss's site where you will find a great pdf. Site is in German but I've supplied him an English translation that can be downloaded from there.

https://www.skrauss.de/

I used a Mega 2560 board for my carriage because I needed to drive an LCD display and I already had all the bits in my electronics collection - but any of the small processor boards could be used for a very compact device. The sniffer code isn't pretty - it is just a quickly hacked down version of the larger sampler program.

The commented Arduino sniffer and sampler code and the interface diagrams (plus some other rubbish) can be downloaded from

https://mega.nz/folder/U...A#xyaaqkKX0ypSpaHtTKZENw

Edited by user 19 November 2024 04:02:00(UTC)  | Reason: Not specified

Link reloaded - works when I test it - let me know if the problem persists and I will try something more drastic.

Also, corrected interface diagram, 47pF capacitor on wrong input.