Lesson 012 – Light sensor (advanced)
You need:
iTriangle online, light sensor, push button switch, 8x8 LED display
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8x8 LED display |
Push button switch |
Light sensor |
Introduction:
Light is the visible part of the spectrum of the electromagnetic radiation that surrounds us. Light is characterized mainly by colour and intensity, which depends directly on the light source. Light intensity is a physical quantity denoted by E and expresses the amount of light (luminous flux) falling on a surface. Its unit is lux (lx). The differences in light across Europe can be somewhere around 0.5 lx at night and up to 70,000 lx during the day. To measure the whole available spectrum, light sensors would need an enormous range. For this reason, the light sensor in this kit is set for much lower spectrum, as it is more accurate in lower light settings.
Task:
Measure the ability of different types of filters to allow light to go through them. Measure the differences between various materials, colours and thicknesses.
Tutorial:
- Construct a simple stand with iTriangle online and connect the sensors and components as pictured below. Connect iTriangle online and upgrade its firmware by following these steps.
- Choose a light source and different types of filters.
- Start the program.
- Press the push button switch to start the program. Measurements will repeat 20 times. If the light measured is lower than the value set in the program, the LED display will light up. Streets lights automatically turn on and off in a similar way.
- You can try different types of filters and distances of the filters from the light sensor (e.g., white or coloured paper, colourful plastics, glass, sun glasses or a glass alternately filled with liquids of different colours. You can also discover the different beam angles of various light sources (diodes, LED light bulbs, incandescent light bulbs, candles or similar).
Extra mile:
Examples of good practice:
Technical notes:
It is important to position the light sensor where other light sources will not affect the measurements (different light conditions outside or changing light conditions inside a room).
If the light is too strong (direct sunlight), the sensor will become saturated. Its maximum measurable value is 1023. If you need to measure the strength of the light source, you can do so in the graphical representation of the measurements.
Related tasks:
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