IT is actually possible to build a very simple pedal yourself. You can tape two tinfoil "electrodes" on cardboard and fold it so that they touch when it's completely folded. Then also put some sponge between the folded cardboard so that it releases reliably. If you connect a mono audio cable to the electrodes you have a working pedal. This worked in a pinch for an electronic drum set and it is also much quieter than a real pedal.

I did something similar once, entirely in hardware, by soldering a normally-open foot pedal switch to the keyboard's controller chip.

In most keyboards, a keypress is registered during the connection of two conductive pads on two separate membranes, each of which contain a trace back to a controller chip. You can take a keyboard apart, look at where the Ctrl key is, then visually follow the traces back to their respective pins on the chip. Soldering a switch to those two pins will register with the keyboard exactly as if that key were pressed.

That's a neat, different way to do it. Nowadays I think most people would go straight to building something with Arduino (e.g. http://apcmag.com/arduino-project-usb-foot-operated-mouse-sw...), but that's not always necessary.

Cool, low budget hack requiring almost no additional hardware! The author states that "the signal is too strong for our input and goes off-scale, making it almost impossible to reliably detect pedal press/release events". Since the two waveforms are visually quite distinct, it is probably possible to correlate the incoming signal with reference on and off waveforms to detect a state change reliably without using hand-crafted heuristics.

On the one hand I cringe at using the audio input for effectively a DC signal, but on the other hand it is probably sitting there unused on a lot of machines so it isn't like you're losing a capability. As with many folks I'd probably use a small uC and have it emulate a keyboard (maximal re-use of known interfaces) but hats off to the creative use of pulseaudio.

The troll of the day:

> How about using ViM?

Thanks for sharing, this post made my day.

I needed a programmable USB foot pedal for my Linux system, as I wanted a hands free way to give a presentation, so I bought one from https://www.delcomproducts.com/webpage.asp?id=32 for $40.

this project is great! after a quick research, it seems that esd might be a bit outdated now [1] and that more recent sound API could be used. it seems however to do the job just fine.

[1] http://www.linuxquestions.org/questions/programming-9/esound...

Is anyone using a pedal in addition of a keyboard on a daily basis? Do you really think this could be a significant help when typing code?

Now this, my friends, this is a hack.

Obligatory complaint about Blogspot breaking back-button functionality; cmd-[left arrow] does nothing, cmd-[right arrow] takes me to the next article.

Who thought this was a good idea?

Pedantic, but that's not a TRS connection.

I see an iKKEGOL USB foot control switch on Amazon for $13.99. Can't you hook that up to any software?

Would a voltage divider help the overvoltage problem?

I remap LALT to CTRL so i can hit it with my thumb