touchdevelop api

apiaccelerometermeasure acceleration

Disclaimer: This document is provided “as-is”. Information and views expressed in this document, including URL and other Internet Web site references, may change without notice. You bear the risk of using it. This document does not provide you with any legal rights to any intellectual property in any Microsoft product. You may copy and use this document for your internal, reference purposes. © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, and Windows Live are trademarks of the Microsoft group of companies. All other trademarks are property of their respective owners.

touchdevelop api

accelerometero electronic component that measures tilt and

motion• angle device is being held at

• movements such as rotation

• motion gestures such as swinging, shaking, and flicking

o detect whether the phone is held in “portrait” or “landscape” mode

o control games and other applications (such as music player) by moving or shaking the phone

touchdevelop api

3d coordinatesY is positive

when this edgeis “up” Z is negative

when this edgeis “up”

X is negativewhen this edgeis “up”

Y is negativewhen this edgeis “up”

Z is positivewhen this edgeis “up”

X is positivewhen this edgeis “up”

touchdevelop api

3d coordinateso length: o on Earth, when phone is steady,

direction changes depending on tilt

touchdevelop api

3d coordinates

Quiz: what is when…o phone is flat

on tableo you slightly

tilt ito phone stands

is upright

Y is positive when this edgeis “up” Z is negative

when this edgeis “up”

X is negativewhen this edgeis “up”

Y is negativewhen this edgeis “up”

Z is positivewhen this edgeis “up”

X is positivewhen this edgeis “up”

touchdevelop api

eventso shakeo phone face upo phone face downo phone portraito phone landscape lefto phone landscape right

touchdevelop api

apiso Senses→has accelerometer

Indicates whether accelerometer is present on device

touchdevelop api

apiso Senses→acceleration quick

Gets filtered accelerometer data using a combination of a low-pass and threshold triggered high-pass on each axis to eliminate the majority of the sensor low amplitude noise while trending very quickly to large offsets (not perfectly smooth signal in that case), providing a very low latency. This is ideal for quickly reacting UI updates.

o Senses→acceleration smoothGets filtered accelerometer data using a 1 Hz first-order low-pass on each axis to eliminate the main sensor noise while providing a medium latency. This can be used for moderately reacting UI updates requiring a very smooth signal.

o Senses→acceleration stableGets filtered and temporally averaged accelerometer data using an arithmetic mean of the last 25 'optimally filtered' samples, so over 500ms at 50Hz on each axis, to virtually eliminate most sensor noise. This provides a very stable reading but it has also a very high latency and cannot be used for rapidly reacting UI.

touchdevelop api

apiso Senses→is device stable

Indicates whether the device is 'stable' (no movement for about 0.5 seconds)

More precise when a gyroscope is also present:o Senses→motion

Gets the current phone motion that combines data from the accelerometer

o Motion→accelerationGets the linear acceleration of the device, in gravitational units.

touchdevelop api

exampleso accelerometer graph

☁ http://touchdevelop.com/anlc o accelero colors

☁ http://touchdevelop.com/wnny o bouncy balls

☁ http://touchdevelop.com/ojfl o turtle o meter

☁ http://touchdevelop.com/lkon o paddle game

☁ http://touchdevelop.com/awic

touchdevelop api

exercise►read accelerometer data:

action main while true do var p = senses→acceleration quick p→post to wall time→sleep(1)

o when running, tilt phone slowly in different wayso shake phone

touchdevelop api

exercises►map vector to background color

• use board

►bonus exercise: level• use just one axis

touchdevelop api

homework►finish exercises at home