Bringing maker education and computational thinking to the classroom.
How Turbid is Your Pond? Using Computer Systems to Monitor the Environment
All components could be used in other projects except those with very minimal costs e.g. LEDs, LED holders and resistors, roughly $10 in non-reusable parts.
computer science, lab science
Students will build a system that monitors turbidity levels in a body of water. They will learn about using a light dependent resistor (LDR) and light emitting diode (LED) together to monitor the level of light, lumens, that passes through the water. Students will use the Arduino programming language to control the processes. They will use a range of readily available electronic components to build the system.
Arduino, programming, light dependent resistor (LDR) , light emitting diode (LED), liquid crystal display (LCD), water pollution
Students need to be aware of what is meant by pollution and turbidity in water. They would benefit from having some initial background in working with small electrical components. Similarly, having prior exposure to programming would be of use.
Students need not be required to program as code is supplied. However, students with prior programming experience would be able to extend and modify supplied code.
Introduction / Motivation:
We are going to investigate water turbidity and how this can be monitored over time. Using electrical components, we will build a system that uses light to measure how much material is suspended in the water. The experiment will run over a number of days so that we can collect readings to test the system. We will record how long it takes water to become turbid. As part of our experiment, we will agree the readings act as measurement of turbidity.
To test our system we will run the experiment in different locations in and out of the lab. This will provide us with knowledge of how an engineering system is affected by different environmental factors, particularly the light available in the environment.
When building the system, we will develop our knowledge of electrical components such as light sensors, LEDs, mini screens and resistors.
Starting from a simple circuit that measures light, we will develop and test our system, refining as we go. We will test the components and judge suitability for solving our environmental monitoring system. In doing this, we will learn how components work together to serve a purpose. The system we will use is the Arduino programming language. The code provided to drive the system allows you to work with variables and functions to investigate how code can be developed.
You will investigate how computer code is constructed and how it can be modified to ensure that our system provides the best possible results.
Some familiarity with programming discipline and basic electrical components will be useful but not essential. Additionally, prior to building the water quality monitoring system, encourage your students to investigate the topic, perhaps as homework:
Students will develop an understanding that water quality can be judged by how far or deeply we can see through the body of water. From this, students should be encouraged to fine tune the idea so that they can discuss scales of visibility.
Procedure 1 - Create basic LDR test system:
Procedure 2 - Set up the LCD:
Procedure 3 - Create the pollution cradle
Figures 6 & 7
Figures 8 & 9
Ready for testing!
With the system components it would be possible to go even further:
Recording data in a classroom environment
Recording data in the field
Navigate by LDR