Several months ago I bought an industrial switch that would be used to operate something like a commercial sewing machine. It's mounted in a heavy metal body that rests on the floor and the pedal is set at an ergonomic angle. It has two sets of contacts. When you step on the spring-loaded switch, it breaks the first set of contacts and makes the second set. When you release the switch, it restores the first circuit. The generic type is a make-break-make, or single pole, double throw switch that's momentary in one direction.

I'm pretty sure that Roland pedals are normally closed, i.e., the circuit is conductive ("closed") by default. When you press a Roland pedal, it opens the circuit. When you release, it closes the circuit. So a switch like the one I bought with two circuits, opens and then closes the circuit potentially very quickly, with one pedal press.

By connecting both sets of contacts together, I thought that this switch would emulate a quick press-and-release when I stepped down on it, and again when I let up. However... it turns out that there is a minimum interval needed to activate built in functions like Bass Inv. I discovered that you can actually press the pedal so quickly that the keyboard doesn't reliably detect the change. Through experimentation I learned that the BK-9 was faster processing and more sensitive than my old E-50. The BK-7m was slightly faster still. But none of them reacted consistently enough to use this approach practicing or playing.

If I have something custom built with an Arduino, it will have to continuously compare the present state of the footswitch with what's in memory to reliably detect a change of state. It would also need to have programmable delays that could be set from "real time" to a few hundred milliseconds. This customizability would ensure that it would function consistently with any vintage of equipment. Discussion boards suggest that I'm not the only one searching for a "toggle to momentary pulse" trigger device. But as of last year, I didn't find any that were mass-produced commercially.

The MIDI solutions Footswitch controller with its capability for "on release" messaging must also have built-in logic for analyzing the state of the pedal. Since it uses MIDI and can be merged into the MIDI stream, it leaves the FC7 port, hold, and footswitch available for other functions.

I've only messed with the D-Beam a little. The lighting in my dining room is tricky. Keyboard is by a large window, so it actually varies by time of day. Other than the harp, chimes, etc., I think I would rather trigger the other functions with footswitch or the assignable switches.