This site describes several DCC decoders with RS-Bus feedback, including a switch decoder, a relays decoder and a feedback (occupancy) decoder. Also a DCC/RS-bus monitor is described. All decoders share a similar design, are easy to build and connect. For most decoders the RS-Bus feedback is provided via an add-on board. Functionality of the decoders can be modified via Configuration Variables (CVs).
Motivation
Around 2003 I started building my own H0 train layout, based on the DCC system. I have several LENZ master stations (LZV 100) and boosters, and originally selected LDT as the main source for DCC decoders. Although these decoders worked reasonably well, after a while I kept having the following problems:
Wiring became too complex, since too many boards were needed to provide certain functions (for switch feedback two boards were needed: S-DEC-4 and RS-16-O; for removing power from tracks in the shadow station three boards were needed: RS8, SA-DEC4 and separate "high current" relays),
Feedback of switch positions remained unreliable (using S-DEC-4 and RS-16-O),
Block occupancy feedback decoders (LDT RS-8) did not allow modifying (programming) the delay times, causing frequent jitter to occur,
Block occupancy feedback decoders (LDT RS-8) had too simple detection logic, and do not allow changing the sensitivity.
There is no decoder that lets my computer control the various camera modules I have (I'm now using Traincontroller Gold).
The decoders described on these pages were designed to solve these problems.
Who should be interested
The decoders described on this site will be primarily interesting for anyone who:
Would like to build his/her own DCC decoders.
Likes to use RS-Bus feedback. Originally my RS-Bus software routines were hard to reuse by others, but lately an Arduino library has been created. This library can be used by anyone who likes Arduino's, but would like RS-bus feedback. Note that the RS-bus is a development by Lenz Elektronik GmbH, and supported by LZV100 / LZV 200 master stations.
Relation to OpenDCC
The decoder hardware and software is inspired by and based upon the OpenDCC project. In fact, this site can be considered as a "spin-off" of the OpenDCC project, and anybody interested in this site should therefore also see the "real thing". Wolfgang Kufer is the driving force behind the original OpenDCC project, and most credits should therefore go to him. Note that OpenDecoder software is available for non-commercial purposes under the GNU license.
Relation to Arduino
Originally there was no relationship with the Arduino ecosystem. Lately parts of the software (such as the RS-Bus feedback) have been rewritten for Arduino. New designs are Arduino compatible from the start.
Hard- and software
The Schematics and Printed Circuit Boards (PCBs) can be found on my EasyEda homepage. From there you can easily (modify and) order PCBs. Costs for PCB production via jlcpcb will be a few Euro for 10 PCBs. Note that all original boards use through hole components, and are therefore easy to solder. Nowadays I'm switching to SMD components however, which will be assembled by jlcpcb since assembly costs are just a couple of Euros.
The software can be found on my github page.