if deviceShaking() - with Accelometer

Code Sharing
1

Some time ago I introduced my drawing app. The app implementes some neat ideas, like mirroring the canvas, by rotating the device by 180°. Now I wanted to implement “shake-to-reset”, like shaking the device to erase canvas and reset the colors, etc. But there was no native option for shake detection. So I used the accelometer and created a function, which you can run inside draw() to check whether the device is being shaked or not.

Shake your device a few times and you should get a message in the output window - or shake it continuously…

-- Accelometer Shake

supportedOrientations(LANDSCAPE_RIGHT)

function setup()
    print("Shake a few times until the rect() exceeds the ellipse().")
end

local function deviceShaking()
    local acceleration = UserAcceleration
    local intensity    = 4 -- adjust min. shaking intensity to trigger this event!
    if UserAcceleration.x > intensity or acceleration.y > intensity or acceleration.z > intensity then
        _deviceShakeUpdatedAt = ElapsedTime
        _deviceShakeBegunAt   = _deviceShakeBegunAt or ElapsedTime
        
        -- first shake triggers listening process
        -- listen if shaking continues for [x] seconds then device is considered shaking on purpose
        if (ElapsedTime - _deviceShakeBegunAt) >= .5 then return true end
    end
    if _deviceShakeUpdatedAt and (ElapsedTime > (_deviceShakeUpdatedAt + .5)) then
        _deviceShakeBegunAt   = nil
        _deviceShakeUpdatedAt = nil
    end
    return false
end

function draw()
    if deviceShaking() then
        print("DEVICE SHAKING")
        background(255, 60, 25)
    else
        background(100)
    end
    
    translate(WIDTH/2, HEIGHT/2)
    noFill()
    stroke(0)
    strokeWidth(2)
    rectMode(CENTER)
    ellipse(0, 0, 100)
    rect(UserAcceleration.x * 40, UserAcceleration.y * 40, 10)
end

```
2

@se24vad Nice code. I had to reduce the intensity value to .1 before I could get it to work without shaking my ipad Air extreamly hard.

3

I choose a hard intensity to avoid accident shaking. But you can fine tune it to your needs :wink: