Light Sensor Challenges

The temperature sensor integrated into micro:bit detect the ambient temperature in Celsius degrees.

Challenge #1: Digital Thermometer

A thermometer is an instrument used to measure temperature. The most common type consists of a sealed glass capillary tube ending in a small reservoir containing a certain amount of mercury or alcohol. This mercury or alcohol expands when the temperature rises and contracts when it falls, and the resulting volume changes are read on a graduated scale.

Digital thermometers use transducer devices and electronic circuits to convert the small voltage variations into numerical values, ultimately displaying the temperature on a screen.

Objective.

Display on the LED panel the temperature detected by the temperature sensor integrated into the micro:BIT.

Code description.

We suggest using the ‘forever’ event, which is in the ‘Basic’ category. This block allows the code entered to be executed during all the program.

Add the "show number" block, located in the Basic category. This block displays the entered number on the LED screen, scrolling it if it has more than one digit.

Replace the number “0” with the value obtained from the temperature sensor. This block is located in the Input category.

Next, the screen is cleared and a 1000 ms pause is introduced. The program then looks like this:

A vertical bar will appear in the simulator allowing the temperature to be adjusted; the selected temperature is the one displayed on the LED panel.

Extra exercise.

Create a program that displays the temperature in degrees Celsius when button A is pressed, and displays the temperature in degrees Fahrenheit when button B is pressed.

Challenge #2: Warning: patches of ice.

Most cars feature a snowflake-shaped warning light on the dashboard, next to the outside temperature display, to alert the driver to the potential presence of ice patches on the road. This light typically illuminates when the temperature drops below 3 degrees Celsius.

Objective.

Display a snowflake icon on the micro:bit's LED panel when the temperature is below 3 degrees.

Code description.

To start the program, it is proposed to use the "forever" event. Next, the "if... then" logical operator, found in the Logic section, must be added. This block checks whether a condition is met; if so, it executes the entered instructions.

To check if the temperature is below 3 degrees Celsius, the operator that returns "true" whenever 3 is greater than the value reported by the temperature sensor will be used. The block is located in the Logic category.

To display a snowflake-shaped icon, the "show LED" block will be used; the "clear screen" block must also be added so that the LED panel does not remain lit when the temperature rises above 3°C, but with a delay to make sure that the signal is visible.

Once the code is finished, the ice symbol will appear when the temperature drops below 3°C.

Extra exercise.

Add an audible alert when the temperature drops below 3 degrees Celsius.

Challenge #3: Optimal refrigerator temperature

The optimal temperature for a refrigerator is 7°C, while a freezer's temperature should be around -18°C. Some refrigerators feature an audible alarm that activates when the temperature is not optimal.

Objective.

Display the refrigerator temperature on the micro:bit's LED panel and activate an alarm when the temperature exceeds 7°C.

Code description.

This challenge incorporates a speaker as an external actuator. One terminal will be connected to GND and the other to PIN 0.

To start the program, the "forever" block will be used. Inside it, the "if-then" condition will be placed. The condition to check will be: if the temperature is greater than 7 degrees.

If the value is true, an alert tone will play.

The measured temperature is also displayed.

In the simulator, the temperature can be varied to verify the correct operation of the program.

Information extracted and translated from catedu.