Vernier Software and Technology
Vernier Software & Technology

Aquarium Monitor


Goldfish are some of the most popular pets, third only to cats and dogs. They live in a large tank of water, called an aquarium. Fish are able to “breathe” underwater, because their gills extract dissolved oxygen from water. To keep goldfish healthy, their aquarium must be continuously monitored. The temperature of the water is one of the most important properties, because even though goldfish are considered coldwater fish, sudden changes in temperature can shock or even kill them. The alkalinity or hardness of the water is also important. Goldfish produce a large amount of waste after eating, which releases harmful chemicals into the water. Fish owners can reduce the alkalinity of aquarium water with additives.

In this project, your challenge is to build a sensor-controlled robot to monitor the water in an aquarium. Your robot should periodically measure the temperature and alkalinity values, and store the data in a file. You will use a Vernier Stainless Steel Temperature Probe to measure temperature and a Vernier pH Sensor to measure alkalinity. The water in the aquarium is considered “healthy” if the temperature is between 20–23°C (68–75°F) and the alkalinity is between pH 6–8. One idea described here is to build a device that hooks over the side of your aquarium and uses two motors to lower the probes into the water, one at a time, every fifteen minutes. Your program can be written to continuously monitor your aquarium night and day for an entire month.

Design Requirements

In this project, you will design and build a stationary device for monitoring the water in an aquarium. Build your device in such a way that all electrical connections will remain dry. Since you will be monitoring your fish tank for a long period of time, configure your program so that it stores the temperature and pH readings in a data file for later analysis.

You are strongly encouraged to use the Engineering Design Method when creating your device.

Sensors and Equipment

This project features the following Vernier sensors and equipment.

Additional Requirements

You will also need NXT Sensor Adapter and a LEGO MINDSTORMS NXT robotics system.

Standards Correlations

See all standards correlations for Vernier Engineering Projects with LEGO® MINDSTORMS® Education NXT »

Vernier Engineering Projects with LEGO® MINDSTORMS® Education NXT

See other experiments from the lab book.

1Acidity Tester
2Plant Waterer
3Aquarium Monitor
4Sunscreen Tester
5Audio Assistant
6String Tension Tester
7Cartesian Diver
8Battery Tester
9Solar Tracker
10Migrating Robot
11Magnet Finder
12Mine Sweeper

Project 3 from Vernier Engineering Projects with LEGO® MINDSTORMS® Education NXT Lab Book

<i>Vernier Engineering Projects with LEGO<sup>®</sup> MINDSTORMS<sup>®</sup> Education NXT</i> book cover

Included in the Lab Book

Vernier lab books include word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.

Buy the Book

Dev Reference: VST0443

Go to top