Monday, March 15, 2010

control panel making progress

Last fall I started working on the control panel for staging and Talheim. While I want all switches to be computer-controlled, I also want the ability to press a button on a panel, see the switch points move along with LED indicators on the panel. As early as being a teenager working on my Dad's layout, I loved the chapters about building custom control panels with feedback indicators in Bernd Schmidt's books. I must have read "Maerklin Bahn&Landschaft" a dozen times or more. Still have it, and even though the wiring instructions are not quite up to the times anymore (he wrote for analog AC wiring), the general ideas are as applicable then as they are today.

So, work and other projects don't leave me a lot of time, but last night my little control panel finally successfully threw the first switch.

The panel is made from a lexan sheet with holes drilled for buttons and LEDs mounted in a wooden frame. Buttons and LEDs are soldered to a bunch of cables that connect the panel to the "decoder board". Originally I planned to solder those cables to DB25 plugs so I can disconnect the panel from the decoder board easily. After soldering 150 connections just for the cables to the panels, and another 100+ for the first round of DB25 plugs I dropped that idea and revised the design to hardwire the cables between decoder board and panel.

Why use a separate board to mount the decoders you ask? Space constraints. I don't have a lot of room between laptop, Intellibox and the layout to install a panel in the first place. Furthermore, since I want to be able to run the layout with two operators, I need to fit two people in the rather small space left in the room. Every centimeter counts, so the panel itself is quite compact, and I mounted the Digitrax DS64 decoders (which replace the amnesiac ESU SwitchPilots I'm using for hidden staging) on a sheet of plywood that will be installed under the layout. That decoder board and the control panel are now permanently tied together by eleven 10-connector cables.

The reason for making this removable is that I can wire the decoder board on the work bench. Soldering is soo much easier when you sit on a stool than crouch on the floor under the layout.

The connection to the layout still goes through DB25 connectors. One DB25 plug for the Tam Valley Depot servo decoders. Two DB25's for the DS64 snap switch connections. Those wires will feed into a bank of 36 euro-style terminal connectors ("Lusterklemmen") for easy disconnect and wiring on the layout.

I need to solder the two remaining DB25 plugs for the snap switches, and the remaining  fascia boards for the servo controlled switches. Another 200 or so solder points left ...

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