Twisted Pico Voice Changer

This is my take on the Pico Voice Changer. The original was first published in Pi Magazine #106.

Credit where credit is due

The original was designed by maker Mike Cook.I changed his design by replacing the BCD switch with a Rotary BCD switch and I added a onboard regulator as wel as some extra output to be used for ledstrips or whatever you see fit.

The pcb I designed was sponsored by PCBway. Find good quality at an affordable prize here: PCBWAY.COM

Different modes

1. Output Delayed
2. Reverb
3. Echo
4. Pitch shift
5. Pitch shift two voices
6. Backward ( output will be reversed like talking backwards )
7. Dalek
8. sin wave
9. square wave
10. saw tooth
11. Vibrato
12. Musique concrete

To know more about how these effects work, I suggest you take a look at the original publications in the magpi magazine.

https://archive.org/details/MagPi106/page/68/mode/2up

https://archive.org/details/MagPi107/page/52/mode/2up

You'll need the PCB.

If you live in the EU, ordering a PCB from my tindie story might be the cheapest option:

https://www.tindie.com/products/markdonners/twisted-pico-voice-changer/

However, PCBway, who sponsored the prototype can also provide you a pcb:

Get one at PCBway.com, just click on this link.

To assemble the pcb you have some options:

1. order a pcb without components and assemble all yourself
2. Order a pcb and have PCBwaw assemble it for you
3. Order a pcb and have it partly assembled and add everything else yourself.

Anyway the whole partlist for this pcb is included in a list.

You'll also need a microphone and amplified speakers.

All about the Raspberry Pico

The heart of this schematic is the Raspberry PI Pico micro controller board. I added a rotary switch to select the mode of the voice changer.

Rotary Encoders

Two rotary encoders are used to change the settings.

Audio circuit

There is a audio circuit for the input and for the output. The audio circuit uses it own power line so that there is less disturbance from the microcontroller.

Input / output

You can hook up a condens microphone to the input.

The output needs to be amplified. I used a set of amplified computer speakers.

Get your PCB:

Buy it here

Raspberry Pico, Opamps and Display

1. I used sockets for the opamp for easy changeability.
2. I used pin sockets and headers for the Pico and the Display.

Rotary switch

1. This one is soldered directly onto the pcb, the axes can bu cut the the desired size.

BCD encoders.

I highly recommend to use wires to connect these encoders. I distroyed several encoders ( the little piggyback pcb's) before i was able to get it right. The reason is that these KY-040 encoders come with a single sided PCB without metalized holes. If you want to change the connector to a vertical version you will have a hard time for it to not brake a trace. Better to use wires instead!

The complete sketch is available from the original author:

part 1

part 2

You can edit, compile and upload using the Arduino IDE with the raspberry pico boars installed.

However, the easiest way is to simply drop the assembled hex file onto you Pico.

Press and hold the bootselect button while powering up and your Pico will appear as a USB drive. You can then simple drag and drop the uf2 file. ( find it using the link above (part2) )

Check out this audio Sample

The result is a beautiful PCB with some awesome functionality.

Here is an audio sample of all the things it can do.