micro:bit Light Sensor

This week in micro:bit Monday we are going to discover how to use the micro:bit to detect light.

The micro:bit doesn’t have a light sensor built in, but we can use the LED matrix to detect how much light there is in a room. This can be then used to make a night light, or a light for the front of a scooter or bike or even just attached to you and it will turn on when it starts to get dark.

Let’s take a look at the code.

MakeCode

1. Open MakeCode within your favourite browser
2. Click and drag on start to the left and drop it in the bin
3. Click on Logic Click and drag a if true then else block to the coding area and drop it inside the forever block
4. Click on Logic Click and drag a 0 < 0 block to the code area and attach it within the ** if** block where it says **true**
5. Click on Input Click and drag a light level block to the code area and attach it wihtin the first 0 within the if block type 100 within the second 0
6. Click on Basic Click and drag a show leds block to the code area and attach it within the if light level < 100 then block Click on all the squares to turn them white
7. Click on Basic Click on more Click and drag a clear screen block to the coding area and attach it within the else block.

You are now ready to download the code to your micro:bit and detect light.

Completed Code

EduBlocks

1. Open EduBlocks within your favourite browser
2. Click on Basic Click and drag a **from microbit import *** to the code area and drop it
3. Click on Display click and drag an image = () block to the coding area and attach it under the **from microbit import **. Replace all the 0 with a 9
4. Click on Basic Click and drag a while True block to the coding area and attach it under the image = () block
5. Click on Basic Click and drag an if True block to the coding area and attach it within the the while True block
6. Click on Basic click and drag a 0 < 0 block to the code area and attach it within the True of the if block. Click on the first 0 and type display.read_light_level() click on the second 0 and type 100
7. Click on Display Click and drag a display.show(Image.HAPPY) block to the code area and attach it within the if display.read_light_level() < 100: block
8. Click on Variables Click and drag a image block to the code area and attach it within the display.show block where it says Image.HAPPY
9. Click on Basic Click and drag an else block to the code area and attach it under the if block
10. Click on Display Click and drag a display.clear() block to the code area and attach it within the else block.

Your code is now complete and ready to download to your micro:bit.

Completed Code

Python

1. Open your favourite Python editor
2. Type from microbit import * This imports the micro:bit library
3. Type while True: This creates a loop that runs while the conditions are True
4. Type if display.read_light_level() < 100: This checks that the light level is less than 100
5. Type display.show(Image("99999:" "99999:" "99999:" "99999:" "99999")) This makes the LED display light up if the light is less than 100
6. Type else: This creates a condition for when the light is 100
7. Type display.clear() this clears the LED matrix.

Your code is now complete and ready to download and run on your micro:bit.

Completed Code

from microbit import *

while True:
    if display.read_light_level() < 100:
        display.show(Image(
        "99999:"
        "99999:"
        "99999:"
        "99999:"
        "99999"))
    else:
        display.clear()

Conclusion

That’s it for another week! Come back next week where we will be looking at the micro:bit tilt function.