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!

DIY guitar mute pedal

Guitar Mute Pedal Made From Upcycled Parts

Rockin’ out on your fave guitar is pretty fun for sure but whether your on stage or jamming in your basement, it can be convenient to quickly mute those killer licks. [wozlaser] wanted a mute pedal for his guitar and instead of shelling out the tens of dollars for a commercial version, he decided to build one himself.

This pedal is heavy-duty and made out of metal. If the frame looks familiar, that is because in a prior life this was a control pedal for a sewing machine. [wozlaser] found it cheap at a thrift store. After the internals were taken out, he added a few key parts. First were the 1/4″ input and output jacks that were scavenged from an old stereo system. There is a momentary switch from a VCR and a standard guitar stomp pedal switch mounted all the way in the front of the frame. The wiring is as follows:

DIY guitar mute pedal

The wiring schematic is pretty darn simple, it just grounds and ungrounds the signal wire. As stated earlier, there are 2 switches, a momentary and a push-on/push-off switch. A normal mute pedal would only have one switch but [wozlaser] wanted something special. If you push the pedal all the way forward it will mute or unmute the signal until it is pushed again. When the pedal is in the spring-supported ‘up’ position a lever pushes on the momentary switch, a slight push on the pedal lifts the lever off of the momentary switch to mute or unmute the signal. The function of the momentary switch (mute or unmute) changes with the state of the other switch. This works exactly the same as a 3-way light switch circuit allows two switches to control one light in your house. With this setup [wozlaser] is able to not only mute and unmute his guitar but strum a chord with it off and pulse the chord on to the beat of the music or tap the pedal with some guitar feedback to make the sound cut in and out. All that only cost [wozlaser] a little time and spare parts… and there are no batteries to replace!

Crank Out The Jams With [Dino]’s Fuzz Face

Weekly Hack a Day feature [Dino] is back again, this time with his very own guitar pedal. It’s modeled on a three-transistor Fuzz Face clone and sounds very good in our humble opinion.

Fuzz pedals were some of the first guitar pedals on the market, and for good reason. Their easy construction and simple theory of operation (just amplify sound until the transistor saturates) made them an economical and available pedal for the legends of rock in the 60s. [Dino]’s build follows this tradition of simplicity with a common 2N3904 transistor and a pair of BC547 Silicon transistors. We’re guessing [Dino] couldn’t find any cred-worthy and mojo-giving Germanium transistors, but the result sounds just as good as we could imagine.

To test out his pedal, [Dino] hooked up a [Jack White] style single string lap steel and turned everything up to 12*. The result is rock. Check out the build vid after the break.

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