Student Instructions

Reading the Sound Sensor

The soundSensor.value block allows you to get the current sound sensor reading

Do This

In this app we've already added a text label with the id "sound_value". Using the soundSensor.value block, display the value of the sound sensor.

Tip: You can drag the soundSensor.value block directly into any other block where you could type a value instead.

Student Instructions

Light Sensor Updates

This app is very similar to the last, but we've added a button with the ID "update_button". Write a program that displays the current value of the light sensor every time the update button is clicked.

Do This

Use an event handler to update the text of "light_value" using the lightSensor.value block.

Student Instructions

Make a Thermometer App

While the light and sound sensors have just a raw value with the value property, the temperature sensor is a little bit smarter. Instead of tempSensor.value, there are two properties tempSensor.F and tempSensor.C which convert the raw input value to either Fahrenheit or Celsius.

Do This

Make a simple thermometer app that reads in values from the temperature sensor. Your app can display the temperature in either Fahrenheit or Celsius (or both!)

• Using Design Mode, create a button for updating and a label to display the temperature
• Add an event handler to respond to your update button being clicked
• Add code to your event handler to read the temperature sensor and display the value on screen

Student Instructions

Student Instructions

Data Event

Each of these analog sensors emits a special event called "data" which occurs every time new data comes in from the sensor. Using this event, we can write programs that continually update.

Do This

This is the first program you worked on in this lesson, let's see if we can make it continually update the sound reading using the "data" event.

• Create an event handler to respond to sound sensor's "data" event
• Move the existing code into your event handler

Student Instructions

Change Event

The data event is fine if you don't mind your code running constantly, but sometimes that's not the most efficient solution to your problem. The sensor "change" event only fires if the sensor value has changed since the last reading, which can make sure your program isn't running code when it's not necessary.

Do This

Using the provided event handler, write a program that buzzes the buzzer and updates "temp_value" whenever the temperature sensor reading changes. Place your thumb over the temperature sensor to get it to change and see how your program responds.

Student Instructions

Change Threshold

By default a sensor's "change" event fires every time the sensor value changes at all, even by one. The light and sound sensors are constantly fluctuating, so you probably want the "change" event to be a little less responsive. The threshold property allows you to set how much a sensor should change before considering it a "change" event - so setting soundSensor.threshold = 100 would cause the sound sensor's "change" event only to trigger if its value increased or decreased by at least 100.

Do This

This app changes the background color of the screen whenever the sound sensor value changes, but we want to only respond to big changes in volume (like a loud noise). Use the soundSensor.threshold block to fix it.

• Add a soundSensor.threshold block before the event handler
• Test out which how different threshold values impact the "change" event
• Choose a threshold value that makes the screen background change only when a loud noise is sensed.

Tip: Your threshold depends on how much ambient noise there is in the room, and how much it changes. A threshold that works in a quiet room may not work in a louder classroom.

Student Instructions

Displaying Sensor Readings in Color

In the earlier prediction level you saw how the setScale() method can convert the full range of sensor readings (0-1023) into a range that can be used for RGB values (0-255). Let's build on that idea to make an app that can communicate the current value of all three analog sensors with a single color.

Do This

To start, we just need to set the sensor scales correctly - don't worry about actually setting the color of the background yet.

• Using the sensor.setScale() block, set each of light and sound sensors to the right scale for an RGB color channel.
• Create a variable for each of the three colors and assign each one to the value of a different sensor.
• Use console.log() to test that your variables are in the correct range.

Hint: Order matters. You need to set the scale of a sensor before checking its value

Hint: Remember that the temperature sensor can be read in both Celsius and Fahrenheit - either way it should already give you a value that's within the necessary range for RGB

Student Instructions

Putting Color on the Screen

Now that your sensor data is in a scale that works for RGB, you can go about setting the screen color.

Do This

• Add a setProperty() block and set it to change the screen's background color.
• Add an rgb() block to the last parameter of setProperty().
• Use the three color variables you created as inputs to the rgb() block.

Student Instructions

Continuous Updates

This sensor-to-color app isn't super useful if it only sets the color once when you start the app. You can use the sensors' "data" event to make your app continually update the background color every time the value changes.

Move your setProperty() block into a an event handler for one of the sensors to make the app update continually.

Student Instructions

Challenge

Check with your teacher before pursuing this challenge

Now that you've practiced taking input from the various analog sensors and changing their scale to meet your needs, can you come up with an interesting use for sensor data? It's easy to display the raw numbers coming out of a sensor, but far more interesting to present that data in different ways.

Consider the following ways you might communicate sensor data:

• Use the board outputs
• Change the width, height, or position of a UI element
• Use conditionals to display different images based on sensor values