Two-Channel Guitar Stomp Box Makes Momentary Switches Latching

When we first saw [Maarten Tromp]’s article about a “momentary latching switch” for guitar effects pedals, we have to admit to being a bit confused. When it comes to push-button switches, “momentary” and “latching” seem to be at odds with each other, with different mechanisms inside the switch to turn one into the other. What gives?

As it turns out, [Maarten]’s build makes perfect sense when you consider the demands of a musical performance. Guitar effects pedals, or “stomp boxes,” are often added to the output of electric guitars and other instruments to change the signals in some musically interesting way. The trouble is, sometimes you only need an effect for a few bars, and the push-on, push-off switches on many effects pedals make that awkward.

[Maarten]’s idea was to build a stomp box with momentary switches that act as inputs to an ATtiny2313 microcontroller rather than directly controlling the effect. That way, a bit of code can determine how long the switch is tapped, and activate a relay to do the actual switching accordingly. A short tap of the button tells the microcontroller to latch the relay closed until another tap comes along; a long press means that the relay is held open only as long as the button is held down.

Yes, he could have used a 555, a fact which [Maarten] readily acknowledges, but with some loss of flexibility; he currently has the threshold set at 250 milliseconds, which works for his performance style. Changing it would be a snap in code, as would toggling the latching logic. A microcontroller also makes expansion from the two-channel setup shown here easier.

Looking for more effects pedal action? We’ve got a bunch — a tube-amp tremolo, an Arduino Mega multipedal, a digital delay line. Take your pick!

Surprisingly Stomp-able Soft Switches

Competition sure brings out the brute in people, doesn’t it? So what do you do when you need a bunch of switches you can let people fist-pound or stomp on repeatedly without them taking damage? You could look to the guitar pedal industry and their tough latching switches, or you could simply build your own smash-resistant buttons as [wannabemadsci] has done.

The main thing about these switches is that they aren’t easily destroyed by shoes or angry fists. That’s because the shiny red push-me part of the button is made by cutting a foam ball in half.

Not easily crush-able Styrofoam, mind you — squishy, coated foam like an indoor football. This is mounted to the top of a sandwich made of hardboard and a couple pieces of easily-compressible foam from craft paintbrushes.

A brass washer is mounted to the middle of both pieces of hardboard, and these have wires soldered to them to read button presses. Then it’s just a matter of hooking it to a microcontroller like any other momentary.

There are all kinds of things you could cut in half for the top, like maybe tennis balls. Or, do what [Sprite_TM] did and use inverted plastic bowls.