# How to get integer volts from a keyboard or how to select different outputs with a keyboard

I’m trying to get integer Volt values from a keyboard. I don’t really care if I use the keyboard as V/OCT or as a set of triggers. My goal is to press a key and get 1V, another key for 2V, another for 3V.

What is the best way to achieve this?

To give more context, I’d like to use 8 keys from the keyboard to control the CV input of the 1:8 module from Bogaudio.

One way to achieve this is probably to send constant voltages to a mixer and then control the solo input of each channel via keyboard. Anything simpler?

Keyboard as in QWERTY or piano? On a piano keyboard, each octave represents 1v. So if C1 is 0v, C2 is 1v, C3 is 2v etc

C to G

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From the BogAudio manual. It doesn’t need integer volts.

As a multiplexer, it routes an input to the output under control of the SELECT knob and CV. A -10-10V CV, divided into 16 equal divisions of 1.25V, controls the input selection. A CV between +/-1.25V does nothing; a voltage of 1.25-2.49V will add 1 step to the selection, a voltage between -1.25V and -2.49V will subtract one step, and so on. This value is summed with the knob setting; for example, setting the knob to 4 and inputting a 2.6V CV will send input 6 to the output. When the knob-plus-CV value exceeds 8, it wraps around.

I’d like to use the bottom row of a launchpad that is easier to access, which means I’d have 8 keys from B-1 to F#0 and all the semitones in-between. I tried to create a semitone-to-octave mapping but it was not very promising

I would instead use this to select one of 8 using a midi note:

(oops, host-gate in the picture - changed to midi-gate)

Rereading you post, you probably want to use VCV Library - ML Modules TrigSwitch 1->8

remapping the triggers, is as simple as clicking a note in the grid, and pressing a key on the midi controller.

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Paul Pikos solution is more specific to Bog Audio but generally you just have to multiply the voltage by 12 to have each semitone one octave higher. You can use the const add mult module as in Paul’s example.

For sure there are different ways to get what I need, but this Triggered Switch 1 to 8 from ML modules does exactly what I needed and in a simple way.

Thanks everybody for the inputs and ideas.