The SPOKE board comes pre-installed with CircuitPython and the relevant code and libraries to work as a universal USB-MIDI device.

This means it should work straight away out of the box as a USB MIDI device. So simply plug it into your device, select CircuitPy, or Pico as the MIDI device in your DAW, and start touching the pins! Alternatively, use the Play tab above to use some of the web-based audio tools.

On Apple devices it recognises the board as a keyboard for some reason, just close that message and you’ll be able to select the MIDI device.

In order to change what the SPOKE does, we need to edit the code on the raspberry pi pico.

A simple step-by-step guide can be found here.

The pads on the board are using capacitance in order to tell the board when to send messages to your device. We can add objects with crocodile clips to the board, but will likely need to reset the board to get it to work again. This is because we have changed the capacitance connected to the pin, so a new threshold for the hardware needs to be made. We can either use the reset button, or just unplug it and plug it back in.

Anything with capacitive potential can be clipped on to the pins. This can be pretty much anything metallic, or conductive inks which are rich in graphite, conductive threads, fruits, vegetables or even thick pencil drawings. You can experiment quite easily by just clipping things on and seeing if it works!

You can use crocodile clips, or solder on permanent wires, use crimps, or nuts and bolts. Anything that will keep still and make a secure conductive connection will work.

The SPOKE-MINI has the same functionality as the main SPOKE board.

However, you will need to be able to solder your own cables to the board in order to create your own touch-sensing objects.

A more in-depth look at the SPOKE-MINI can be found here.

This page has a guide to MIDI Note values

If you are confident in soldering and basic electronics, it’s not too difficult to create your own capacitive touch sensors using the RPi Pico.

This page here breaks it down a bit clearer for you.

When you power up SPOKE, it automatically calibrates each of the capacitance levels of each sensor pins.

When you add an object, it changes that amount of capacitance being measured, but doesn’t YET alter the threshold for triggering an action like sending a MIDI note.

All you need to do, is hit the RESET button on the front. OR attach your objects before plugging the board in.

This way when the board powers up, it automatically calibrates the sensors with this new object attached and sets a new threshold for when to trigger.

Alternatively, this page allows you to get into the nitty gritty of what the sensors are doing.

Yes, you can.

In most cases you won’t need to, as the board ‘calibrates’ each pin on power-up or after you’ve pressed reset.

You can change the sensitivities in the code either manually, or use our interactive Debugging page to adjust individual pin sensitivities

If you received one of the first 100 boards from the Kickstarter campaign, there is a tiny piece of circuitry missing which means if you use a USB-C cable into a USB-Socket on your device, it won’t recognise the orientation of the cable and so won’t send power or communication from the host side.

There is a simple fix, by using an OTG Convertor and a USB-C to USB-A cable. If you are a kickstarter backer and need a converter, get in touch and we will send you one.

The Raspberry Pi Pico is the brains of the whole thing. We are using the circuitpython coding language and specifically their touchio library to control everything on the board. The sensing we are using measures something called capacitance. This is the ability for an object to hold a charge. On our board, we make the Pico add some charge to a pin and then measure how quickly that pin ‘discharges’ back to the board. This measurement is happening very quickly, all the time, and we can control the speed of the discharge by adding a large resistor in the circuit. So we now have a constant amount of time that the pin is being charged and discharged, then charged again and discharged again. When we touch that sensor, we change how long the pin takes to discharge by adding extra material that can hold charge, and so the Pico will go “hey, something’s changed””. And THAT is the part where we tell our code to do stuff.

Anything that has capacitive potential.

• Pretty much any metallic object, wire, pipe, keys, tools, cutlery, coins, nails, bolts, jewellery, swords, tinfoil etc.

• Fruits and Vegetables

• Conductive threads

• Conductive inks

• Thick pencil drawings (darker pencils work better as they’re more rich in graphite)

• Copper tape

• Plants

• Liquids

Another fun thing you can do is measure capacitance THROUGH objects. If you were to have a large surface area of conductive material on one side of an object, it will be able to sense when you are close to the surface but not physically touching. So you could cover a thin piece of wood on one side with tin foil and try touching the wooden side to trigger the boards pin.

Yes you can. You will need to do a fresh install of the circuitpython environment. Head here and go through the steps to NUKE your board, followed by installing Circuitpython. When your board comes back as a Circuitpy device, you will need to grab the adafruitmidi and adafruithid libraries from the libraries bundle here. PLEASE NOTE, If you install version 9 of circuitpython you will need to use the library bundle for version 9.
After you have done this, you can head to the Github page and copy/paste any of the example code into the code.py file.

It is similar but very distinct.

Boards like MakeyMakey and Playtronica use a technology called Resistive touch. This means you need to complete a circuit by holding a ground connection and then touching the sensor pin.

SPOKE uses capacitive touch, which means the board is measuring how much electrical charge it can hold on each pin, and when you touch the pin, the value changes, and that’s when it triggers a response.

In short, with SPOKE you don’t complete a circuit, you just touch a sensor. It is more akin to the BareConductive Touchboards which are no longer in production.

Each type of touch has its own benefits, it all depends on what project you are building.