John Hill

Obviously I cant drive the tracks directly from the output of the sound card but my software does cause the sound card to output DCC format signals and it is just a matter of using the motor driver chip to up the power enough to drive the tracks, the other IC just trues up the shape of the signals that are distorted by the audio output circuit. All the controller software is in the PC, my software looks really crude but I hope it will prove easy to use. Right now I can put about a dozen 'trains' on the screen each one with a throttle, brake, reverse button that can be operated by a finger on the touch screen. If it works well I might develop that "human interface" a bit more! I have talked to a few train guys but I never struck the right person! Of course just mentioning that I was using this for LEGO brought fourth a whole horde of folks with ideas totally at odds with mine! If I can get this to work I will certainly be going back to those boards as some guys did express genuine interest.

I have a number of 9V trains I have converted for DCC by installing the decoder chip in the motor housing but as we all know this is rather difficult to do in a 12V motor so I have an alternative. For 12V DCC I install the decoder chip outside the motor, two wires to the motor sockets and two wires to copper brush pickups that contact on the metal 9V rails. The 12V pickups I just hold in the fully up position with tape. This system works well except that the copper brush pickups are not the best idea and I hope to make metal bogey wheels to improve the contact. The copper brushes are tufts of copper braid taken from old computer cables and held near the wheels of a bogey with hot glue which sticks well to LEGO and can be easily peeled away when required. Some people tell me that I will "fry my 9V motors" by running them on 12V DCC but I dont believe them and so far I have not had a single 9V motor failure. My theory is that as the 9V motors are being fed PWM there will be no stress on the motor unless attempts are made to drive them at faster or heavier loads than they would have been able to handle on 9V DCC. This is fortunate because I can mix 12V motors and 9V motors on the same track, the 12V trains may be down on power a bit and I expect I could increase the DCC volts a bit (15V maybe) without stressing anything. I hope you find this interesting and maybe useful.

I have fitted a few of my LEGO trains with DCC and have a commercially made DCC controller. Unfortunately the controller is very difficult to operate and although I could no doubt buy a better one I have chosen to experiment with writing software and using a PC. I have chosen not to use anything like an Arduino but instead am trying to create the DCC signals direct from a PC under Winderz, in the past this would have been easy but since the operating system has put increasing separation between the user and the real world it has become more of a challenge especially as PC parallel ports now seem to be a thing of the past. The route I have chosen is to have my software write ".wav" sound files containing the DCC signal forms. The only complication encountered so far is that the sound device must be programmed for a non-standard sample rate and not all sample rates work however 17250 samples per second does, at least with my sound device. The only 'electronics' required is an LM339 chip as a comparator and an LMD18200 H-bridge motor driver IC. I am using a PC power supply for 12V for the track and 5V for the ICs. Results so far have been promising but not totally satisfactory with the train occasionally pausing or putting on a burst of speed. I presume there are caused by the DCC decoder getting corrupted packets although it is difficult to see how this could be happening with each packet having a check byte. I would like to check the wave form but my analogue scope is only partly useful and I would be grateful for any suggestions on how to do this. Thanks. I have just merged your two topics about DCC. In principal the same topic. (JK)

This might sound really weird but has anyone made a "vertical transverser"? (A horizontal transverser is a system where sections of track move horizontally to carry tramcars, locos and other rail vehicles between parallel tracks serving a purpose similar to a turntable.) In my case I have a special LEGO room that shares a wall with the garage and I would like to have a number of trains set up in the garage ready to go through a hole in the wall out into the "real" LEGO world! I could use a few switches and have about four storage tracks in the garage (or even a regular style transverser) but space in the garage is limited. So, the notion is that several tracks could be mounted on a frame attached to the wall so that it could be moved up or down to bring the desired train to the level of the track going through the wall. Has anyone seen such a system?