pxt-calliope/docs/projects/step-counter.md
2018-10-22 13:22:50 -07:00

1.8 KiB

Step Counter

A @boardname@ attached on a foot

This project turns the @boardname@ into a simple step counter. A step counter is also known as a pedometer. Each shake event increments a counter variable. The step count is displayed on the LEDs.

~ hint

If you built a watch in the make portion of the of the Watch project, you can use the code from this project with it too.

~

A counter

To build a counter, we'll need a variable to store the number of steps.

let step = 0
step = 0

Detecting a step

Assuming you attach the @boardname@ to your foot or ankle, it will get shaken when you take a step. We can use the ||input:on shake|| event to detect a step (it should notice a step most of the time). Let's add the code to increment step by 1 when the @boardname@ is shaken.

let step = 0
input.onGesture(Gesture.Shake, function () {
    step += 1
})
step = 0

How many steps so far?

We want to always see how many steps were counted. In a ||basic:forever|| loop, we add a ||basic:show number|| block to display the value of step.

let step = 0
input.onGesture(Gesture.Shake, function () {
    step += 1
})
basic.forever(function() {
    basic.showNumber(step)
})
step = 0

Display lag

Did you notice there is a lag, or delay, in the display of steps? This is because the step value can change while the @boardname@ is displaying a number. To remove the lag, add ||led:stop animation|| after changing the value of step.

let step = 0
input.onGesture(Gesture.Shake, function () {
    step += 1
    led.stopAnimation()
})
basic.forever(function() {
    basic.showNumber(step)
})
step = 0