Curricullum iTriangle online

Lesson 001 – Cool world

You need:

iTriangle MASTER online, waterproof thermometer, buzzer, 8x8 LED display, push button switch

Waterproof thermometer buzzer

8x8 LED display

Push button switch

Introduction:

Throughout history, it has always been important to understand how hot or cold the different things we come into contact with in our daily life are. Early on, people determined temperature by simply touching or coming into close contact with things. In this lesson, you can compare your ability to estimate temperature with real measurements from a waterproof thermometer.

Task:

Tutorial:

  1. 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.
  2. Mix hot and cold water in a cup so that it is around 35–37 °C. Students can practice their own estimation of given temperatures.
  3. Start the program.
  4. After you press the push button switch connected to the MASTER, the thermometer will start measuring the temperature of the nearby surroundings. Depending on the temperature, the following can happen:
  • If the measured temperature is between 35°C and 37°C, the LED display will show a happy face and the buzzer will play a melody.
  • If the measured temperature is above 37°C, the LED display will show a sad face and the buzzer will produce a short, high-pitched beep.
  • If the measured temperature is below 35°C, the LED display will show a neutral face and the buzzer will produce a short, low-pitched beep.

 

Extra mile:

Feel free to change the temperature limits in the program (see yellow circles) so that students can try to mix water for  different temperatures.

Examples of good practice:

Technical notes:

Lesson 002 – Cooling effects of volatile liquids

You need:

Step 1: iTriangle MASTER online, 2 bowls (we used plastic bottles), water resistant thermometer, pure alcohol, water

Step 2: iTriangle MASTER online, 2 bowls, water resistant thermometer, pure alcohol, water, 2in1 temperature and humidity sensor, buzzer

 

Waterproof thermometer

Buzzer

2 in 1 sensor – temperature and relative humidity

  

Introduction:

There are times when it's important to cool down. We don't mean times when we're angry, but situations when things are too hot for us.

Task:

Two tasks are prepared for you. Both assess the difference between the evaporation of water and alcohol. Can you guess which one evaporates more quickly and is therefore better at cooling the surface it is applied to? Think about it and try to prove it with the following experiments.

Tutorial:

Step 1:

  1. 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.
  2. Pour water and alcohol into separate bowls. Place the thermometer into the bowl with water and wait for the temperature to stabilize. After another five seconds, remove the thermometer and sharply shake off any excess liquid and leave it to dry freely.
  3. Start the graphical measurements.
  4. The temperature should start lowering. When the temperature starts rising again, you can finish your measurements. Follow same instructions using the alcohol instead of water.
  5. When finished, compare the data and decide which of the two liquids lowers the temperature more quickly and is more volatile.

Step 2:

  1. Re-use the stand from the previous step with iTriangle online.
  2. Pour water and alcohol into separate bowls. Place the thermometer into the bowl with alcohol and wait for the temperature to stabilize. After another five seconds, remove the thermometer and sharply shake off any excess liquid and leave it to dry freely.
  3. Start the program.
  4. The thermometer rod's temperature will be measured ten times, while the 2in1 sensor will measure the  temperature and humidity of the environment.
  5. There are two possible outcomes.
  • If the temperature of the environment is higher than the temperature of the thermometer rod, the buzzer will produce a long tone.
  • If the temperature of the environment is lower than the temperature of the thermometer rod, the buzzer will produce a short tone.

Extra mile:

You can adjust the program any way you want (change the buzzer's tone or add more sensors)

Examples of good practice:

 

Technical notes:

After removing the thermometer from the liquid, make sure to sharply shake off any excess liquid. This will also make the liquid cover the sensor in a thin layer needed for measurements.

Let the liquid stand at room temperature for around 30 minutes before starting the experiment. It is important that the water and alcohol are the same temperature as the surroundings.

Because the water-resistant thermometer measures at its tip, dipping the rod just halfway into the liquid is enough.

Lesson 004 – Gears

You need:

iTriangle MASTER online, IR gate, buzzer and construction set

   

Infrared gate

Buzzer

    

Introduction:

Cogwheels or gears working together are called a transmission. Transmissions transfer the rotational effects of an engine (a "drive") or other equipment to another part of the machine (e.g., a wind power plant). The drive and driven mechanism in this experiment will be gears. A handle on the first gear will be the drive, and the driven mechanism will be another gear next to the first gear.

 

Tasks:

  1. Connect the gears to rotate in opposite directions.
  2. Connect the gears to rotate in the same direction.
  3. Connect the gears to make the driven wheel rotate more quickly.
  4. Connect the gears to make the driven wheel rotate more slowly.

In the tasks above, count how much faster / slower the driven wheel is than the drive wheel. Use the IR gate to count the number of revolutions of the driven wheel.

 

Tutorial:

  1. Connect the gears to rotate in opposite directions.

You can use any of the gears. If they are connected as pictured, they will always rotate in opposite directions regardless of their size.

  1. Connect the gears to rotate in the same direction.

To make two wheels rotate in the same direction, you need to use a third wheel between them. The size of the wheels is not important in this task.

  1. Connect the gears to make the driven wheel rotate more quickly.

To make the driven wheel rotate more quickly, use one bigger and one smaller wheel. When the drive wheel is bigger than the driven wheel, the driven wheel is faster. Can you guess what happens when you use a smaller wheel as the drive?

  1. Connect the gears to make the driven wheel rotate more slowly.

If you did the previous task easily, you may have already found the answer to this task. Which wheel do you need to make the other one turn more slowly? Is it the bigger or smaller one?

  1. Use the IR gate to count the number of revolutions.
    1. 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.
    2. Connect the wheels to the stand as pictured below.
    3. Start the program.
    4. Start turning the drive wheel. Now comes the challenging part. To compare the number of revolutions of each wheel, you need to count how many times you turn the handle as well as how many beeps the buzzer produces. Do you find it easy or hard to do two things at once?

Extra mile:

Now is the time to do some math. With the help of the equations below, can you calculate how much more quickly or slowly each driven wheel is compared to the drive wheel? Create different combinations of wheels and compare the revolutions of the driven and drive wheels. Write your findings in the table below. Compare the results and answer the following question—is there a correlation between the number of teeth on each wheel and number of revolutions of the driven and drive wheels? Explain your findings.

 

Example:

If the driven wheel has three times more teeth than the drive wheel, then the driven wheel will have three times less revolutions than the driven wheel.

 

Worksheet:

Gear parameters:

d1 ... drive wheel diameter; d2 ... driven wheel diameter

z1 ... number of teeth on the drive wheel; z2 ... number of teeth on the driven wheel

N1 ... number of revolutions of the drive wheel; N2 ... number of revolutions of the driven wheel

Depending on the method and combination of gears, the drive and driven mechanism can rotate either in the same direction or oppositely, with the resultant rotational movement of the driven mechanism accelerated (transmission to faster speed) or decelerated (transmission to slower speed). Another option is direct transmission, where the speeds of the drive and the driven mechanism are the same.

Quantitatively, the transmission characteristic is given by the ratio i, which is calculated as follows:

i = d2 / d1 = z2 / z1 = N1 / N2

If i < 1, then transmission is to a faster speed; if i = 1, then it is direct transmission; if i > 1, then transmission is to a slower speed.

There are 3 types of gears in the set:

  1. Yellow gear with 60 teeth
  2. Blue gear with 40 teeth
  3. Red gear with 20 teeth

Examples of good practice:

Technical notes:

IR Gate can be a little challenging to operate. To make it easier, make sure there is plenty of light around but without direct sunlight and no shadows. You might need a small screwdriver to adjust the sensitivity of the IR gate by turning the small white disc in the blue casing. This usually only needs to be done once.

 

 

Instructions for connecting to iTriangle online and starting measurements

Connecting the iTriangle online unit to code.itriangle.cz:

You can connect your iTriangle online unit to the online environment in three ways:

  1. Connect to the WiFi network through Huawei E5730s.
  2. Connect to your WiFi with WPAPSK security protocol via an Android app.
  3. Connect to a predefined WiFi.

Updating the iTriangle online unit's firmware

  1. Select "Projects" on the left hand side at code.itriangle.cz.
  2. Find the lesson you want to proceed with. Click on the three horizontal lines on the left side and select "Upload online block program" and connect the sensors according to the picture on the right.
  3. Select iTriangle with the icon you set when you connected the iTriangle online unit to WiFi. This should automatically start uploading the settings of your choice.
  4. Wait for the message "Firmware was successfully updated" to display.
  5. Your iTriangle online unit is now updated with the lesson of your choice and you can start with the experiments.

Starting graphical measurements

  • Follow "Connect the iTriangle online unit" to code.itriangle.cz and the "Update the iTriangle online unit's firmware" section. Then select the "Measure" button at the left of the screen.
  • Select iTriangle with the label you set when you connected the iTriangle online unit to WiFi by clicking on the box on the left side of the screen under the 'Nodes' section.
  • In the "Modules" section below, the sensors connected to the iTriangle online unit will be displayed. By clicking "Start" at the top of the page on the right, you can start measuring and creating graphical representations of measurements.

Starting programs

  • Follow "Connect the iTriangle online unit" to code.itriangle.cz and the "Update the iTriangle online unit's firmware" section. Click on the "Start" button above the displayed code to start a program.

Lesson 005 – Mechanical oscillation (pendulum)

You need:

iTriangle MASTER online, IR gate, buzzer

   

Infrared gate

Buzzer

    

Introduction:

Oscillation is a regular, rhythmic movement between two points. Its magnitude of instantaneous speed therefore varies.

Task:

Determine the dependence of the pendulum's oscillation period on the weight of the pendulum bob and the length of the pendulum bob's suspension.

Tutorial:

  1. 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.
  2. Prepare the pendulum.
  3. Start the program.
  4. Press the push button switch to start your measurements.
  5. Using a timer, measure the time for five periods of oscillation. To automatically determine the number of oscillations, use the IR gate to trigger the buzzer when the pendulum passes near it. Write the measured time into the table below and recalculate it for one period.

Oscillation parameters

Amplitude – the maximum distance the pendulum bob moves away from the center point

Period (T) – the time of a full swing back and forth of the pendulum (measured in seconds)

Frequency (f) – the number of periods per second s-1 = Hz (s-1 = frequency units; Hz = Hertz)

f = 1/T

Worksheets

Pendulum bob – dependent on weight only, length of suspension is same for all measurements

Weight (number of attached wheels)

5 periods (10 T / s )

1 period ( T / s)

 

 

 

 

 

 

 

 

 

Pendulum bob – dependent on length of suspension only, weight is same for all measurements

Length of the bob's suspension

5 periods (10 T / s )

1 period ( T / s)

Full

 

 

Half

 

 

Quarter

 

 

Extra mile:

Examples of good practice:

Technical notes:

 

 

 

Lesson 006 – Cooling effects of sprays

You need:

Step 1: iTriangle MASTER online, aerosol, chloraethyl spray, local anesthetic in spray, volatile liquid, water-resistant thermometer

Step 2: iTriangle MASTER online, aerosol, chloraethyl spray, local anesthetic in spray, volatile liquid, water-resistant thermometer, 2 in 1 temperature and humidity sensor, buzzer

 
Buzzer Waterproof thermometer 2 in 1 sensor – temperature and humidity  

Introduction:

A spray (aerosol dispenser) is used to dispense liquid substances as small particles dispersed in gas (aerosol). With a given volume of liquid, its surface area and hence rate of evaporation will increase (the larger the area, the faster the evaporation). Evaporation intensity is also increased by the presence of volatile liquids used as propellant in the spray. The aerosol removes heat from its surroundings, resulting in rapid temperature drops.

Chloraethyl spray can, for example, reduce surface temperatures to below -50 °C. Common sprays can achieve -5 °C with continuous application (20 to 25 seconds). Medical grade sprays can achieve deep, below zero temperatures in under seven seconds.

Task:

Cool the metal rod of the water-resistant thermometer to below 0 °C. Rapid evaporation of aerosol (spray) applied directly to the rod makes this possible.

Tutorial:

Step 1:

  1. 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.
  2. Apply spray to the metal tip of the waterproof thermometer in two different ways:
    1. First, spray continuously for seven to eight seconds
    2. Second, spray repeatedly in short intervals of one or two seconds
  3. Start the graphical measurements.
  4. After each application, the temperature should start decreasing. When it starts increasing, you can stop measuring. In both measurements, compare the differences in how quickly the temperature changes.
  5. Now it's time to make your own observations according to the graphs you created. Which situation shows a more rapid fall in temperature? Is it the first when you spray for a longer time, or the second when you spray more often for shorter times?

Answer: when is the spray applied for a longer time, the temperature falls more quickly. The reason is that the spray does not have chance to evaporate quickly enough while more of the spray is applied. When is the spray applied repetitively for shorter times, the temperature falls in steps. This is because the spray can evaporate between each application, giving the surface of the rod time to absorb heat from the surroundings.

Step 2:

  1. Re-use the stand from the previous step.
  2. Apply the spray to the metal tip of the thermometer.
  3. Start the program.
  4. The following two situations can occur:
  • If the temperature of the environment is higher than the temperature measured by the waterproof thermometer, the buzzer will produce a short tone.
  • If the temperature of the environment is lower than the temperature measured by the waterproof thermometer, the buzzer will produce a long tone.
  1. With the measurements from above, we can find the difference between the change in temperature of the waterproof thermometer relative to the temperature of the environment.

The program will measure ten times before stopping.

Extra mile:

Examples of good practice:

Technical notes:

Lesson 007 – Cooling mixture

You need:

Two bowls, waterproof thermometer, salt, iTriangle online, buzzer

   

Waterproof thermometer

Buzzer

    

Introduction:

When water changes to a solid as it freezes, its temperature does not change. All heat lost caused by a cooling mixture causes a change of state of the water. Only after the water in the container has solidified will additional heat loss result in a drop in temperature to lower values. In this experiment, the cooling matter (the cooling mixture) removes heat from warmer matter (water). The experiment verifies the understanding that the temperature of the substance does not change during its change of state.

Explanation of coolant temperature (crushed ice + sodium chloride):

Ice melts at 0 °C. The ice-salt mixture has a melting point substantially lower (down to -20 °C). When crushed ice is mixed with sodium chloride, the ice will start melting rapidly because the mixture has a much higher temperature (about 0 °C) at that time than its freezing point. To melt ice in this way (breaking its crystal structure) requires energy (heat) to be removed at the expense of the total temperature of the salt water produced. Salting the crushed ice at a temperature of about 0 °C turns it into salt water whose temperature drops down to between -15 °C and -20 °C. The lowest temperature we can reach is -20 °C. Lower temperatures can not be achieved. For this reason, it does not make sense to sprinkle roads with salt. Practically, however, sodium chloride stops dissolving at temperatures below -8 °C to -10 °C. Defrosting is only effective at these values.

Task:

Create a cooling mixture that can freeze water. This experiment will show you how water behaves when it changes state.

Tutorial:

Step 1:

  1. 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.
  2. Prepare a mixture of crushed ice and salt (2 parts of ice to 1 part of salt) in a bowl. Mix both together thoroughly and insert the waterproof thermometer into the bowl.
  3. Start the graphical measurements.
  4. Watch how the temperature of the mixture falls. When the temperature stops falling, you can stop measuring.
  5. The temperature of the mixture can fall to as low as -18 °C. To achieve this, you might need to stir the mixture continuously, which you can do with the thermometer directly.

Step 2:

  1. Re-use the stand from the previous step.
  2. Prepare a mixture of crushed ice and salt (3 parts of ice to 1 part of salt). Mix both together thoroughly. Take another bowl with water and place it on top of the cooling mixture. Insert the waterproof thermometer into the bowl with water.
  3. Start the graphical measurements.
  4. Watch how the temperature of the water falls. When the water turns to ice, you can stop measuring.
  5. The temperature of the water can fall as low as -12 °C. To achieve this, you might need extra cooling mixture prepared on the side.

Step 3:

  1. Re-use the stand from the previous steps.
  2. Prepare a mixture of crushed ice and salt (3 parts of ice to 1 part of salt). Mix both together thoroughly. Take another bowl with water and place it on top of the cooling mixture. Insert the waterproof thermometer into the bowl with water.
  3. Start the program.
  4. The program will take measurements 10 times.
  5. There are two possible outcomes from the measurements.
  • If the temperature is higher than 0 °C, the buzzer will produce a short tone
  • If the temperature is lower than 0°C, the buzzer will produce a long tone
  1. Leave the water in the cooling mixture until it becomes solid. If needed, you can start the program again. You also can change the number of measurements to 20 or higher or a lower number.

Extra mile:

Examples of good practice:

Technical notes:

Lesson 008 – The light around us

You need:

iTriangle MASTER online, light sensor, push button switch, buzzer, 8x8 LED display, construction parts as shown in the picture below

Push button switch Light sensor Buzzer 8x8 LED display

Introduction:

The most natural way of measuring light is with your own eyes. In this experiment, we will make some quantitative measurements and try how the light sensor from the iTriangle kit works compared to our own eyes.

Task:

Measure the strength of light in different locations.

Tutorial:

  1. 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.
  2. Make sure there is enough light nearby and ideally in different places.
  3. Start the program.
  4. Press the push button switch connected to the MASTER, and the light sensor will start actively measuring the nearby light. According to the strength of the light, the following can happen:
  • If there is enough light, the LED display will show a happy emoji
  • If there is not enough light, the LED display will show neutral emoji
  • If the sensor detects even less light, the LED display will show sad emoji
  • If it is completely dark, the LED display will show a sad emoji and buzzer will sound

The measurements will stop after one minute or if the sensor is in complete darkness for a few seconds.

Extra mile:

Move the set around the room and try to find out how much light is in different locations. Try with your own eyes whether you can see the difference in strength of the light as well as the sensor can. You can also draw a grid on paper of the classroom and note in each space how much light you measured. You can create a colourful work of art if you give each of the four possible measurements a specific colour.

Try using different types of filters over the light sensor to see how different colours and materials allow light to pass through. You can use cling film, colourful see-through foils,  papers of different colour and thickness, aluminium foil, a ruler, an empty glass, a glass filled with coloured lemonade, or any other materials.

Now is the time to change the program any way you want. Change the limits of the light, how the LED display behaves according to the amount of light or connect another sensors or components. To make it easier for you, please see the picture below with descriptions of different parts of the code.

(PIC)

Light sensors are widely used in streets to turn on street lamps when it gets dark. You can setup a warning signal when it gets too dark in your room. Sometimes you may need more light for reading but do not realise it. This can let you know when to switch on your room lights.

Another option is leaving the kit in one place and measuring the change of natural light over a whole day. For long term measurements, the graph shown at code.itriangle.cz is useful for this purpose.

Examples of good practice:

Understanding how our eye works is important, and it is good to try to find the differences in how our eyes perceive light and the measurements from the light sensor. Try to guess what kind of filters will let through more or less light. First make some assumptions using only your eyes and then try to prove it with measurements.

Because the program creates a noise when the light sensor is in complete darkness, you could create a creature that does not like being touched on the back of its neck. See the example we created below. It's an oversized worm that will start screaming and make an unhappy face when it is touched at the back of its neck. When the worm has enough space and light around, the worm is happy and quiet.

(PIC)

What did you create? We would like to show others what you made, so please share your creations with us! :)

Technical notes:

The light sensor is not designed to measure direct sunlight. If used under direct sunlight, the sensor may be over-saturated with light and any measurements done may not be accurate.

Lesson 009 – Motion sensor PIR

You need:

iTriangle online, PIR motion sensor, buzzer

   

Buzzer

PIR motion sensor

    

Introduction:

Detect the motion of an object using a PIR sensor that responds to infrared light emitted by the moving object.

Infrared radiation is a part of the electromagnetic spectrum that is invisible to the human eye. All objects that have a temperature above -273.15 °C (0 Kelvin) emit this thermal radiation. The natural temperature of human is around 37 °C. People therefore emit a large amount of heat that can be measured by PIR motion sensor.

The PIR sensor measures temperature in different segments of its field of view. The temperature measured by each segment is individually evaluated and recorded for comparison with other segment measurements.

Task:

Find out how long the PIR sensor needs to detect a movement near the sensor. Every type of PIR sensor has different setting and sensitivity. In this task we will check the sensor's settings. Examine what the sensor can detect according to the size, temperature and speed of an object.

Tutorial:

Step 1:

  1. 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.
  2. Choose an object you want the PIR sensor to detect.
  3. Start the graphical measurements.
  4. If the sensor detects an object, the graph will show a value of 1. If no object is detected, the value is 0. Find out how long the sensor needs between detected movements (value 1 does not immediately change to 0 – there is a set delay in the ability to detect movements).
  5. Calculate the arithmetic mean of delay from the measured values and use these findings in the next step.

(example of measurement results)

Step 2:

  1. Re-use the stand and settings from the previous step.
  2. Choose the object you want the PIR sensor to detect according to its size and temperature. The speed of its movement will also play a part.
  3. Start the program.
  4. When you move the object around, the PIR sensor and the sensor will be able to detect it and a buzzer will play a tone. If nothing is detected, the buzzer will stay quiet. Make sure you give the sensor enough time to recover from each detection (you measured this recovery time in the previous step).
  5. What did you find out? Are different objects detected in the same way? What role do temperature and speed plays in detecting movement?

Extra mile:

Putt a blanket into a freezer until it is frozen, then cover yourself with it and move in front of the sensor. Does it detect you? What if you hold a paper cover between you and the sensor? Can you trick the sensor?

Examples of good practice:

Technical notes:

The PIR sensor can detect state changes only over longer time periods. The recovery time between two consecutive detections is about 5 s.

Lesson 010 – Burglar alarm

You need:

iTriangle online, 4 in 1 sensor, buzzer

   

4 in 1 sensor

Buzzer

    

Introduction:

An accelerometer is a sensor that measures how quickly an object moves from its rest position. The 3-axis accelerometer can simultaneously measure acceleration values ​​in the x, y and z axes. An accelerometer can be used to construct a motion vector, i.e., the direction of movement in space and the acceleration value in the given direction. Acceleration is reported in units of G, which is the acceleration due to gravity. For humans, acceleration or deceleration of around 20G will result in internal organ damage and death.

Task:

Learn how a 3-axis accelerometer works. Use a long cable to connect the accelerometer to iTriangle online so you can move the 4 in 1 sensor away from the rest of the construction. Construct a movement detector and use it as a safety module to detect the movement of the object it is attached to.

Tutorial:

Step 1

  1. 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.
  2. Choose an object you want the PIR sensor to detect.
  3. Start the graphical measurements.
  4. Try to move the sensor each time along one axis so that the measured value is constant – the acceleration along the given axis is constant. Another option is to move the sensor so that the acceleration value is zero – the speed is constant.
  5. What is the difference in sensor movements along different axes and at different speeds?

Step 2

  1. Re-use the stand and settings from the previous step.
  2. Attach the iTriangle online to an object of your choice that you want to have an alarm (cars usually have these alarms against burglars).
  3. Start the program (you can set limit values for the buzzer to start making noise – make sure it's not too low or high, some tweaking with the limit numbers might be needed)
  4. Challenge others to move your object from one place to another and hope that you set the alarm correctly!

Extra mile:

Place the sensor at rest in one place. If the value along one or more axes is non-zero, why? What is the value of the acceleration / negative acceleration (deceleration) you get by clapping your hands with the sensor in one of them?

Construct a movement detector and use it as a safety module to detect the movement of the object it is attached to.

Examples of good practice:

Technical notes:

The z-axis extends vertically upwards, the x-axis extends lengthwise from the connector across the sensor plate and the y-axis extends perpendicular to the x-axis along the description on the printed circuit board. Axis orientation is indicated on the printed circuit board for the following sensors: magnetometer, accelerometer and gyroscope.

Lesson 011 – Soil moisture sensor

You need:

iTriangle online, soil moisture sensor, LED display 8x8

 

Soil moisture sensor

Buzzer

8x8 LED display

  

Introduction:

The humidity sensor measures the current passing through individual electrodes. This current is dependent on the humidity and chemical composition of the monitored environment. The more water (ions) present in the environment, the more conductive the environment. A humidity sensor detects small currents in mA and low DC voltages up to 3.3V. However, weak electrolysis also takes place in the monitored environment. A very small amount of corrosion will occur on the electrodes, which will accumulate salts over a long time. The pH of the environment may also change over a longer period because of the chemical reaction. To prevent these phenomena from happening in long-term measurements, do not measure continuously for long periods and limit measurements only to a few per day.

Task:

Learn how to detect moisture in the soil of a plant and understand the principle of this measurement. Create an indicator for a plant that lets you know when more it needs more water.

Tutorial:

  1. 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.
  2. Choose an object you want the PIR sensor to detect.
  3. Start the program.
  4. Four things may happen:
  • If the water content is high, a happy face will show on the LED display
  • If there is just enough water present, a neutral face will show on the LED display
  • If there is not enough water in the soil, a sad face will show on the LED display
  • If the soil is too dry, a sad face will show on the LED display and the buzzer will make a sound

The program will run for 60 seconds  until "End of program" is shown on the LED display. The length of the program and  values for when different faces are shown on the LED display can be changed.

Extra mile:

Examples of good practice:

Technical notes:

Over time, corrosion will occur and the electrodes will lose their shine. To prolong the sensor’s functionality, clean and dry the electrodes thoroughly after each experiment. Do not use the sensor to measure the conductivity of alkaline or acidic liquids.

Lesson 012 – Light sensor (advanced)

You need:

iTriangle online, light sensor, push button switch, 8x8 LED display

 

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:

  1. 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.
  2. Choose a light source and different types of filters.
  3. Start the program.
  4. 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.
  5. 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.

008

Lesson 013 – Burglar alarm (advanced)

You need:

iTriangle online, PIR sensor, buzzer

 

Buzzer

Push button switch

PIR motion sensor

  

Introduction:

Infrared radiation is a part of the electromagnetic spectrum that is invisible to the human eye. All objects that have a temperature above -273.15 °C (0 Kelvin) emit this thermal radiation. The natural temperature of human is around 37 °C. People therefore emit a large amount of heat that can be measured by PIR motion sensor.

The PIR sensor measures temperature in different segments of its field of view. The temperature measured by each segment is individually evaluated and recorded for comparison with other segment measurements.

 

Task:

Use the motion detector (PIR sensor) that reacts to infrared light emitted by an object in motion. Construct a simplified version of a burglar alarm.

Tutorial:

  1. 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.
  2. Choose the objects you want the alarm to detect.
  3. Start the program.
  4. To activate the burglar alarm, continuously press the push button switch until the buzzer produces two tones. The first tone is lower in pitch and second is higher. When you hear the second tone, release the push button switch. Now check what kind of objects it can detect. When the PIR sensor detects movement, the buzzer will play a melody as an alarm. You can deactivate the alarm by pressing the push button switch at any stage of the program – when you hear the high and low tones, you can release the push button switch and the alarm will be deactivated.
  5. The program is initially set to operate for one minute only. This time can be extended by adjusting certain values in the program.

Extra mile:

Examples of good practice:

Technical notes:

The PIR sensor can detect state changes only over longer time periods. The recovery time between two consecutive detections is about 5 s.

009

Lesson 003 – Measuring the relative humidity of the environment

You need:

iTriangle online, 2 in 1 humidity and temperature sensor, polyethylene bag, straw, bowl made from a plastic bottle

      

2 in 1 sensor – humidity and temperature

      

Introduction:

The relative humidity of air indicates the ratio of the instantaneous amount of water vapour in the air to the water vapour content of the air at the same pressure and temperature at full saturation. It is stated as a percentage (%). Relative humidity is dependent on the air temperature and the amount of water vapour it contains. The higher the temperature, the higher the amount of water vapour the air can absorb. Conversely, the lower the temperature, the less water vapour the air can contain.

The human body contains water in all its cells, its blood and tissue fluids. The body excretes water through breathing, sweating and passing urine. Water is replenished in the body through the intake of food and drink. The recommended daily intake of water is up to 3 liters. Without food, a person can survive for 14 days, without water, only a few days. This is why drinking enough water is very important.

Task:

Learn about the relative humidity of a place of your choice (your classroom, a corridor or outside) and compare it to the relative humidity measured in an open area with a bowl of water placed below the sensor, or a closed space with a bowl of water placed inside. At the end, you can check the humidity of your own breath.

Tutorial:

Step 1:

  1. 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.
  2. Decide on a place where you want to make your measurements.
  3. Start the graphical measurements.
  4. Observe the measurements for the open environment and any changes in humidity.
  5. We can verify experimentally the dependence of relative humidity on the differences in parameters such as:
    • the surface area of the water where we make our measurements
    • the distance of the water's surface to our measuring device
    • the temperature of the water's surface where we make our measurements

Step 2:

  1. Re-use the stand from the previous step.
  2. Fill the bowl from the plastic bottle with some water and place it under the sensor. Wrap everything into a polyethylene bag.
  3. Start your graphical measurements.
  4. Observe for changes in humidity in the closed environment.
  5. Water will evaporate and increase the relative humidity of the enclosed air until it is saturated with water vapour. A longer time is needed for these measurements. Compare and discuss the results of measurements from steps 1 and 2.

Step 3:

  1. Reuse the stand from the previous steps and remove the moisture sensor from the holder.
  2. Place the moisture sensor into a polyethylene bag and insert a straw so that one end of the straw is inside and one end is in the open air. Seal the bag.
  3. Start the graphical measurements.
  4. Blow air in through the straw continuously and observe the changes in the graphical representation of the closed environment's humidity.
  5. Write the results of your measurements into the table below:

Relative humidity of my breath

Relative humidity of an open space

Relative humidity above a freely placed bowl of water

Relative humidity of a closed environment inside a polyethylene bag containing a bowl of water

 

 

 

 

 

 

 

 

 

Step 1:

Step 2:

Step 3:

Extra mile:

 

Examples of good practice:

 

Technical notes:

 

Sample lesson

You need:

iTriangle MASTER online, buzzer, LED display, 2 in 1 humidity and temperature sensor, light sensor

Buzzer LED display 2 in 1 humidity and temperature sensor 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:

Find out how the intensity of incident light changes depending on the light source, the distance from the light source and type of filters placed between the sensor and light source.

Tutorial:

  1. 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.
  2. Choose a light source and different types of filters.
  3. Start the program.
  4. Measured light values will be shown on the display. The display also shows measurements from the 2 in 1 humidity and temperature sensor. You can look at other lessons to see how to use the 2 in 1 sensor. 
  5. Try different types of filters and place them at different distances 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).

Measurements on LED display:

Temp – temperature in °C

Humid – relative humidity in %

Lumin –- luminescence measured in a relative scale


The online block programming is set up to measure the temperature, relative humidity and light levels 50 times and show the values ​​on the LED display.

The Arduino program also continuously measures temperature, relative humidity and light and writes values ​​to the display. According to the amount of incident light, the buzzer will simultaneously play (or not play) different tones. If you reduce the amount of light to the sensor, the tones will also reduce. You can create a melody by moving the sensor between darker and lighter areas of illumination. Try using different light sources.

Technical notes:

 

 

WIKI iTriangle

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