diode matrix with tortoise switch machines?

There are lots of ideas for roll-your-own circuits on Rob Paisley's site at:

If the button activates a relay, that relay can be connected via the matrix to power the necessary switches. You will need a mechanism to deactivate the previous relay.

For a "start"/"entrance" and "destination"/"exit" setup you will probably need a diode matrix for each end.

Another post points you to Bob Paisley's site, good stuff. The club I belong to uses a slightly different approach. One button, when depressed, increments an counter. When you release the button at a particular number the corresonding relay, for that yard track, is activated, all others are deactivated. That relay provides + and

- voltage to the diode matrix for that yard track and power to the corresponding track. It uses a Basic Stamp chip to run the led display and activate the relay. The diode matrix is a physical manifestation of a directed path state diagram.

Good luck and enjoy, Paul

There's also another way (probably many "other ways") to accomplish the objective. On my layout I control all yard turnouts via software. I have CTI software and hardware installed

have written the software to allow selection of any yard track by pointing to a button at the end of the track. All switches are aligned for entry/exit. When the train is out of the yard I have a "finished" button that resets the lead for the mainline. Works fine and I can change track colors to show the complete alignment (just like one of the real dispatch centers I saw looked). It works!

There is an article in the August 1987 issue of Model Railroader that has a circuit which will allow you to use pushbuttons and a diode matrix to contol Tortoise switch machines. I have about 3 dozen controlled with this circuit. It works very well.

Also check out . . .

Hope this is helpful.

Paul - "The CB&Q Guy" Modeling 1960's in HO.