A forum member recently contacted me regarding how to mount leds right on his control panel to show the position of various layout turnouts. He needed two types; one type for standard Lionel 022 switches and a second for DZ-1000 controlled switches such as RCS and Gargraves. The result was a couple of new pcb designs which I figured I would put on the forum in case other operators have similar needs.
Many O scale operators like to substitute a toggle switch for the normal OEM turnout control, for reasons of looks or saving panel space. But a common problem with this is how to know which position the turnout is in, particularly if it is not easily visible. This can be very inconvenient, especially if the switches are not of the non-derailing type. These compact indicator boards provide an easy-to-interpret solution that mounts right on the control panel and shows at a glance which position the switch is in by means of a red or green led.
A full size momentary SPDT (ON)-OFF-(ON) toggle switch functions well, but neither it nor the Lionel remote lend themselves to locating on the track plan due to their size. But a “micro” size toggle switch works great for this. The MAIN reason for using a momentary switch is so that once the switch is thrown and released, the control circuit is open and will not attempt to keep the switch in the opposite position if/when the non-derailing feature is triggered.
These small indicator boards can be mounted right at each switch on the track plan, or grouped in a designated area on the control panel. One variant uses a single bi-color red-green led to show turnout position. Another uses individual red & green leds. Both have the same functionality and are ideal for small 3mm bezel mounted leds; though any size led can be used. The leds are the only part that is visible on top of the panel; the wiring and circuit board is all concealed on the underside.
R2.1 version (shown below) is for use with Lionel 022/072 switches, and any similar types that use an internal SPDT switch to tell the circuitry which position the switch is currently in. It can either be assembled with a single bi-color CC led, or with two separate leds per user preference.
R3.1 version (shown below) is specifically intended for turnouts operated by the Z-Stuff DZ-1000 switch machine, including those made by RCS, Curtis and Gargraves. The internal circuitry of the DZ-1000 machine prevents the use of a single bi-color led. Different circuitry than R2.1 is required and separate red and green leds are used. It is reversible and can be built either as a type A for machines mounted on RH switches, or type B for machines mounted on LH switches. In both cases the indicator led color will match that of the DZ-1000 mounted led.
Both the above versions provide the same indications and functionality. Both circuit boards are only 12 x 22 mm in size. Besides the leds there is only 2 other components on each board. Hookup is simple requiring only 3 light #26 wires hooked directly to the momentary SPDT toggle switch. This is convenient if the toggle switch is mounted on the panel near the led location. No outside power is needed to operate the board, power is supplied by the switch operating circuit. Power consumption is less than 15ma each. Full user instructions are included.
Gerber files are included for both board designs below for those who wish to order their own. Optionally I can provide bare boards for simple assembly, contact me offline for more information. There is no BOM as they are both dirt simple; values are shown right on the boards. Easy stuff.
Revised Pdf files are also included providing suggestions for building and using both board styles several posts down.
Let me know if any questions.
Rod
