pxt-ev3/docs/tutorials/security-alert.md
2018-06-12 06:46:44 -07:00

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Security Alert

Introduction @unplugged

The Infrared Sensor uses infrared light waves to detect proximity to the robot. Build an security alert using the Infrared Sensor.

Brick in simulator with infrared sensor

Step 1

Open the ||sensors:Sensors|| Toolbox drawer. Drag out an ||sensors:on infrared object|| block onto the Workspace (you can place this anywhere). Select detected from the second dropdown menu.

Sensor detect method dropdown selections

sensors.infrared1.onEvent(InfraredSensorEvent.ObjectDetected, function () {

})

Step 2

Open the ||brick:Brick|| Toolbox drawer. From the Screen section, drag out a ||brick:show image|| block onto the Workspace, and drop it into the ||sensors:on infrared object|| block.

sensors.infrared1.onEvent(InfraredSensorEvent.ObjectDetected, function () {
    brick.showImage(images.expressionsBigSmile)
})

Step 3

In the ||brick:show image|| block, use the drop-down menu to select the STOP sign image.

Screen image selections

sensors.infrared1.onEvent(InfraredSensorEvent.ObjectDetected, function () {
    brick.showImage(images.informationStop1)
})

Step 4

Open the ||brick:Brick|| Toolbox drawer. From the Buttons section, drag out a ||brick:set status light to|| block onto the Workspace, and drop it after the ||brick:show image|| block.

sensors.infrared1.onEvent(InfraredSensorEvent.ObjectDetected, function () {
    brick.showImage(images.informationStop1)
    brick.setStatusLight(StatusLight.Orange)
})

Step 5

In the ||brick:set status light to|| block, use the drop-down menu to select the red flash light

Status light selection dropdown list

sensors.infrared1.onEvent(InfraredSensorEvent.ObjectDetected, function () {
    brick.showImage(images.informationStop1)
    brick.setStatusLight(StatusLight.RedFlash)
})

Step 6

Open the ||loops:Loops|| Toolbox drawer. Drag a ||loops:repeat|| loop onto the Workspace, and drop it after the ||brick:set status light to|| block.

sensors.infrared1.onEvent(InfraredSensorEvent.ObjectDetected, function () {
    brick.showImage(images.informationStop1)
    brick.setStatusLight(StatusLight.RedFlash)
    for (let i = 0; i < 4; i++) {

    }
})

Step 7

Open the ||music:Music|| Toolbox drawer. Drag a ||music:play sound effect until done|| block onto the Workspace, and drop it into the ||loops:repeat|| loop.

sensors.infrared1.onEvent(InfraredSensorEvent.ObjectDetected, function () {
    brick.showImage(images.informationStop1)
    brick.setStatusLight(StatusLight.RedFlash)
    for (let i = 0; i < 4; i++) {
        music.playSoundEffectUntilDone(sounds.animalsCatPurr)
    }
})

Step 8

In the ||music:play sound effect until done|| block, use the drop-down menu to select information error alarm sound effect.

Sound effect dropdown selections

Step 9

Now, plug your EV3 Brick into the computer with the USB cable, and click the Download button at the bottom of your screen. Follow the directions to save your program to the EV3 Brick.

Attach an Infrared Sensor to Port 1 of your Ev3 Brick. Test your program by putting an object increasingly closer to the Infrared Sensor your Intruder Alert should trigger when you get too close!