Pin Press Switch

Use pin press to switch guitar play on/off

• Concepts:
• Circuit
• Conductor
• Variable/Global-Variable
• Conditional: `if`, `else`
• Boolean: `True`/`False`

Materials:

2-3 Crocodile clips

Blocks

``````let on = false
on;
if (on) { } else {}
input.onPinPressed(TouchPin.P1, () => {})``````

Circuits & Switches

• Circuits need a power supply (battery), a resister (like a LED) & a conductor (metal, water, hand)
• Switches turn electric power on by closing (completing) a circuit with a conductor so power can flow

Metal foil and wires make excellent conductors

In this activity we use YOU to conduct electricity to close the circuit that switches the guitar ON and OFF!

Step 1: Pin Press Test

``````input.onPinPressed(TouchPin.P0, () => {
basic.showNumber(0)
})
input.onPinPressed(TouchPin.P1, () => {
basic.showNumber(1)
})
input.onPinPressed(TouchPin.P2, () => {
basic.showNumber(2)
})``````

Create the pin-press code

Hold the micro:bit touching The GND pin with one hand with the other hand alternately touch the 0, 1 and 2 pins

The electric signal traveled from pins, between your hands to `GND` and the micro:bit detected the electric signal!

How is the touch dectected? Find out in this video:

Step 2: Installing conductive foil on the guitar

Add foil to the guitar body where it is easy to touch while playing

Connect the foil to `GND` using a crocodile clip

Add foil to the guitar neck

Connect the foil to `pin 1` using a crocodile clip

Step 3: Add a switch to turn the guitar ON and OFF

Using the `on` global variable we can switch the message on the micro:bit between ON and OFF

``````let on = false
basic.forever(() => {
if (on == true) {
basic.showString("ON")
} else {
basic.showString("OFF")
}
})
input.onPinPressed(TouchPin.P1, () => {
if (on == true) {
on = false
} else {
on = true
}
})``````

Create the ON/OFF switch code

Test by touching `P1` to toggle the LED message between ON and OFF

Final code TODO: do we want to use `on = !on;` or be more direct in flipping the switch? `on = true; on = false;`

``````let on = false
basic.forever(() => {
if (on) {
music.setTempo(pins.map(Math.abs(input.acceleration(Dimension.Y)),
0, 1023,
60, 320))
music.playTone(
input.lightLevel() * 25,
music.beat(BeatFraction.Quarter)
);
} else {
music.rest(music.beat())
}
})
input.onPinPressed(TouchPin.P1, () => {
on = !on;
})``````

Now Play!

Turn the guitar ON and OFF with a pin press on the connected foil by touching both pieces of foil at the same time to connect the switches