Code

Duration: ~15 minutes

Step 1: wire up the servo

Follow the instructions in servo 101 manual to connect the servo to the micro:bit.

Step 2: code light sensor

Code the lightsensor on the micro:bit to control the servo.

basic.forever(() => {
    led.plotBarGraph(
        input.lightLevel(),
        0
    )
    pins.servoWritePin(AnalogPin.P0, input.lightLevel())
})

It works but your servo might be trying to move too much. Let’s calibrate it.

Step 3: calibrate the servo

Download the servo calibration program to determine to opening and closing angles of the servo for your robot.

We are going to map the light level range, to the angle range, [closed, opened] using pins.map.

let angle = 0
let closed = 0
let opened = 0
basic.forever(() => {
    led.plotBarGraph(
        input.lightLevel(),
        0
    )
    angle = pins.map(
        input.lightLevel(),
        0,
        255,
        opened,
        closed
    )
    pins.servoWritePin(AnalogPin.P0, angle)
})
// TODO: use the angle found at calibration!
opened = 95
// TODO: use the angle found at calibration!
closed = 175