> -----Original Message----- > From: owner-piclist@MITVMA.MIT.EDU > Sent: Monday, June 22, 1998 3:55 PM > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: DC motor speed regulation > > > there are pic controlled trains for as small as 'N' scale > that I have seen > on the web. The pic receives the digital signal (Train id, > and speed) from a > signal on the track. there is a site www.tttrains.com that > has the specs and > if you do an www.altavista.com search for +pic +microchip > +train +hobby > there are many links to poke around. > > michael > > Howdy All, The common standard that is used today in the Model railroading world is the DCC standard from the National Model Railroad Association (NMRA). It stands for Digital Command Control. There are many (6-8) manufacturers in the DCC field (Digitrax, Lenz, Wangrow.. and others). There is quite a lot of information out there on DCC. You might want to start at www.nmra.org. There is a section for DCC and that are links to most of the manufacturers own web pages from there... The standard only states what the signal is on the rails. How each manufacturer gets the signal there is up to them. A brief synopsis of command control: Command control of model trains has been around a long time. General Electric developed a system back in the fifties called ASTRAC, It wasn't too popular and never really took off in the hobby. In the seventies a series of articles in Model Railroader was published covering the CTC-16 system. This was the first major system to gain a wide acceptance in the hobby. It was an analog system. A few years later the CTC-16 system was improved upon to create the CTC-16e. again is was digital. The creator of the CTC-16 system (Keith Gutierrez) developed the system as part of his master thesis for his EE degree. You can get more info at his company's web site: www.cvpusa.com. Other systems came onboard with some of them compatible with the CTC-16 systems and other that were not. There are/were two-three other systems out there that were not compatible with every one else. In the eighties a German company (Lenz) developed a digital system with more capabilities that the other analog systems out. As more companies became interested in the digital system, the NMRA pushed for a standard that everyone can live with and be compatible at the track level. With the standard in place many companies decided to develop systems that adhered to this new way of communication with the locomotive. Back in the seventies the pc boards in each locomotive was quite large compared with today's decoders. With the advent of Surface mount and the Microcontroller these boards can be quite small. The smallest today is about the size of a dime. Like I said earlier the only standard is the signal on the track. As for the way the different systems communicate between each device is different. Some manufacturers use a RS-485 polled network and others use a slowed down version of a Ethernet. Different stroke for different folks... I am in the process of trying to add some devices to one of these networks. As I am new to the PIC world I would certainly welcome any help alone these lines. The system I am working with uses the Ethernet approach. It's slowed down to about 16K baud which is well in the range of the PICs out there to day. Thanks for the bandwidth, Kevin Orcutt Software Engineer Vickers E.S.D., Inc. 1151 W. Mason-Morrow Road Lebanon, OH 45036-9699 (513) 494-5752 - Phone (513) 494-5400 - Fax kevin.orcutt@vickers-systems.com (Work) kntorcutt@fuse.net (Home) #include // "It just doesn't Matter!"