Sensor fish

Key takeaways

Sensor fish belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Sensor fish to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Sensor fish from memory before moving on to harder problems.

Reference excerpt

A sensor fish is a small, plastic tubular device containing sensors. It is designed to record information such as the physical stresses that a fish experiences while navigating currents from dam turbines. The sensors provide accurate, physical measurements for acceleration, pressure, rotational velocity, and orientation, which convey what real fish may experience during downstream passage.

Description

Created by the US Department of Energy's Pacific Northwest National Laboratory (PNNL), the tubular device is 9 cm (3.5 in) long, 2.5 cm (0.98 in) in diameter, and weighs 42 grams (1.5 ounces). It is roughly the same size as a juvenile salmon. The sensor fish has neutral buoyancy allowing it to remain underwater. Inside are sensors and a lithium-ion battery. Taking 2,048 measurements each second, it is able to record five minutes of turbulence, pressure, and acceleration, saving the data to flash memory. It records a maximum of 1.2 MPa (174 pounds per square inch) of external pressure, up to 200 gs of acceleration, temperatures ranging from -40 to 127 °C (-40 and +260 degrees F), and rotational velocity of up to 2,000 degrees per second.

Construction

The sensor fish is built manually at the Bio-Acoustics & Flow Laboratory within the PNNL. It receives funding from the Electric Power Research Institute and the US Department of Energy's Office of Energy Efficiency and Renewable Energy.

Specifications The following are the specifications as stated by the Pacific Northwest National Laboratory:

Power: rechargeable 3.7-volt lithium-ion battery Length: ~90 mm Diameter: ~25 mm Mass: ~42.1g Cost: $1,200 each Gyroscope: Model ITG-3200, InvenSense Inc. Orientation: Model LSM303DLHC eCompass module made by STMicroelectronics, Geneva, Switzerland Usage: Kaplan turbine; Francis turbine; small hydropower structures; pumped storage hydroelectric facilities Memory: ~5 minutes of data with flash memory Speed: 2,048 measurements per second Pressure: Model MS5412-BM, Measurement Specialties, Inc., made in Hampton, Virginia capable of 174 pounds per square inch of pressure Acceleration: Model ADXL377 accelerometer, Analog Devices, Inc. Rotational velocity: 2,000 degrees per second Temperature range: -40 to +125 degrees Celsius using model TC1046 by Microchip Technology Inc. Buoyancy: neutral Other features: There is a device that releases two, small weights after a certain period of time causing the device to come to the surface for retrieval. Four LED lights for retrieval and diagnostics that flash orange, yellow and green

Purpose

Data collected from the sensor fish is used to help create new designs for dam turbines. Aging dams require retrofits and upgrades, and considerations about the impact on fish can be taken into account. The sensor fish was initially designed to examine the effects of the most common kind of turbine in the Columbia River Basin, the Kaplan turbine. Most of the tests were carried out at the Ice Harbor Dam, a 100-foot-high structure. Inside the turbine of that dam, the pressure changes experienced are the same as moving from sea level to the peak of Mount Everest in an instant. In 2015, the sensor fish will evaluate a dam in Southeast Asia's Mekong River, irrigation structures in Australia, a conventional dam as well as three small hydro installations within the United States.

Data acquisition process

The fish sensor is deposited into the fish release tank at the top of the dam. There, it begins recording data as it travels down through the hub release pipe. It then enters and passes through the turbine. From there, it is flushed into the tailrace, and is retrieved by boat. The device is then placed into a docking station where it begins to recharge its battery and awaits transfer of the data it has gathered. The docking station sends the data to a laptop computer over USB using software developed by PNNL. The software can convert the raw, binary data into CSV format, enabling scientists to more easily plot the data.

Earlier version The first version was developed in the late 1990s and was called the "Flubber Fish". It was created to increase the survival rate of salmon during their journey through the Columbia River Basin's dams. It was clear, rubber-coated, and looked like a fish.

Future design The second generation model will be able to accommodate other hydraulic structures and turbines. It has improved sensors for detecting pressure, better accelerometers, and better gyroscopes which detect rotational velocity. Within the device is a radio transmitter. Also, there is a device that releases two weights after a specific period of time. This allows the sensor fish to come to the surface for retrieval.

References

External links

Design and implementation of a new autonomous sensor fish to support advanced hydropower development, Z. D. Deng, J. Lu, M. J. Myjak, J. J. Martinez, C. Tian, S. J. Morris, T. J. Carlson, D. Zhou and H. Hou Technical report: Characterization of Fish Passage Conditions through the Fish Weir and Turbine Unit 1 at Foster Dam, Oregon, Using Sensor Fish, 2012, February 2013 Synthesis of Sensor Fish Data for Assessment of Fish Passage Conditions at Turbines, Spillways, and Bypass Facilities – Phase 1: The Dalles Dam Spillway Case Study, December 31, 2007 Evolution of the Sensor Fish Device for Measuring Physical Conditions in Severe Hydraulic Environments, T. J. Carlson, J. P. Duncan, February 2003

Illustrations

Sensor fish: A Kaplan turbine — A Kaplan turbine

Worked examples

Example 1 — a first encounter with Sensor fish

Start with the simplest possible case. Write down what Sensor fish claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sensor fish before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sensor fish ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sensor fish

In research: Sensor fish appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Sensor fish in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Sensor fish is common in secondary-school and first-year university syllabi. It links to neighbouring topics Sensors, so understanding it makes those chapters shorter.
In everyday life: Look for Sensor fish outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Sensor fish in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sensor fish means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Sensor fish out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sensor fish in simple terms?

A sensor fish is a small, plastic tubular device containing sensors. It is designed to record information such as the physical stresses that a fish experiences while navigating currents from dam turbines.

Why does Sensor fish matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sensor fish?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sensor fish.