vi_pedal

Input / Command - Mode Selection via Foot-Pedal to Teensy

Very simple idea, stolen from someone ( I couldn't remember where but today I stumbled across the blog-post once more with the nice german title: Warum vim so geil ist ) You have a foot-pedal and can send keystrokes with this foot-pedal to your PC (via USB-HID) In this case it is a vi-pedal:

• When pressing the pedal a "i" is sent once and you are in insert-mode
• when releasing the pedal a ESC is sent once and you are in command-mode Thats it.

As usual in my projects (shooting with canons to sparrows...) I used a Teensy. Wiring is rather simple:

    SW               ---------------
----/ ------ GND ----|             |
|                    |    Teensy   |------- USB to PC
-------------12 -----|             |
                     ---------------

That was the original idea. As it turned out, a "proper" pedal, which is intended to be used, does not use a normal switch. Instead it is using a infrared light barrier with a IR-LED and a Phototransistor. So the wiring now looks like this:

+----------+-------VCC-------+
|          |                 |
R2         R1       +--------+-------+
|          |        |                |
|          +----12--+     TEENSY     |------- USB to PC
D1 --->    |        |                |
|  --->    T1       +--------+-------+
|          |                 |
+----------+------GND--------+

A little bit better to understand is the following wiring:

So now the polarity is inverted and the input-pin does not need a pullup. The IR-Diode, Fototransistor and the two resistors are used as they have been in the original pedal, which already was a USB-Pedal. But unfortunately it was not able to produce different keystrokes on push and and on release. So the Teensy with the "intelligence" is needed.

Please see also on my blog here: http://jogiblog.kuenstner.de/2017/05/das-vi-pedal/

Have fun