One of the most interesting electronic parts to come on the market lately is Berrett Hill’s Touch Toggles. They’re little electronic switches that operate by the proximity of your finger. There’s no mechanical movement, so you can put them behind acrylic control panel faceplates and other such and still operate them just by touching the surface. Unlike a mechanical switch, they never wear out, and they come with built-in indicator lights.
We’ve gotten several questions about using them to control our MRServo switch machines, so last fall I purchased a few to try them out. Unfortunately life gets in the way, and they’ve set on my shelf until this evening, when I was adding switch machines to the Nizina staging yard on my Copper River & Northwestern.
Any of the toggling Touch Toggles (as opposed to the momentary versions) are just perfect for controlling MRServo. They operate on +5V DC and provide a logic level output – exactly what we need as an input. The problem is how to easily wire them in, without cutting the end off and soldering them to various places on the board.
Fortunately Berrett Hill has chosen to use the standard RC servo pinout for their connection. While the Touch Toggle’s logic level output won’t drive a servo directly (servos need a pulse width input), +5VDC and ground are on the right pins (+5 on the center, which is usually the red wire, and ground on pin 1, which is typically black or brown). So, with a servo Y-cable, we can get power for the part right off the servo connector, and we can just cut the signal line (usually white or orange) on the Touch Toggle side of the Y cable and connect it to the MRServo control input.
Here’s a video of it in action: