Robotic Measurement System collects photometric data.
Press Release Summary:
Since 2009, EPRI has been conducting LED Energy Efficiency Demonstration in order to try and discover light bulb that meets outdoor lighting requirements of consumers while using less electricity. Assessments have been made for LED-based street and area lights at over 20 sites within US using EPRI-developed remote controlled roving light measurement vehicle named Scotty. This mobile robot can measure all types of lights, including LED.
Original Press Release:
"Scotty" Light Measurement System Integral Component of EPRI LED Street Lighting Demonstration
Today, high-intensity discharge (HID) lighting, such as high-pressure sodium and metal-halide lamps, prevails when it comes to illuminating streets, parking lots and walkways. But high-power light-emitting diodes (LEDs) promise a brighter future in outdoor illumination. Their capacity to send a more pleasing light in one direction makes them an ideal candidate to replace conventional outdoor lighting.
Since 2009, the Electric Power Research Institute (EPRI) has been conducting an LED Energy Efficiency Demonstration. The goal of the project is to discover a better light bulb, one that not only meets the outdoor lighting requirements of consumers but also uses less electricity in doing so.
There are a number of reasons for exploring new LED technology for this application.
EPRI is conducting assessments of LED-based street and area lights at over 20 sites within the United States. The assessments require accurate, repeatable and timely measurements of light levels. Existing test methods require hand-held meters and are time-consuming, of limited accuracy and require manual recording of data. EPRI developed a solution for this measurement challenge. That solution is a remote controlled and highly instrumented roving light measurement vehicle known as "Scotty."
Overview of Scotty - Light Measurement System
Collecting photometric data is a significant measurement challenge. For the EPRI LED street light demonstration, engineers determined that measurements should be made near the ground where light is incident upon walking surfaces. Moreover, the measurements should be made on an exact grid. These two requirements-the height of the measurement and its grid location-posed a difficulty for engineers.
Accurate, timely, and repeatable measurements of LED light levels are possible using the computercontrolled Light Measurement System, nicknamed "Scotty," a four-wheel, technology-laden, remotely controlled robot. Using a global positioning system, Scotty aims its precision light meters skyward, recording light data onto its onboard computer at up to five times per second as an operator maneuvers the mobile device throughout a high-resolution grid. This robot is a versatile device and can measure all types of lights, including LED.
EPRI developed the light measurement system with precision Global Positioning Satellite (GPS) technology and photometric instrumentation to methodically record the required information and log it to a laptop computer.
This mobile light measurement system offers engineers a number of benefits since it decreases measurement time from hours to minutes, increases measurement accuracy from ten-foot grid spacing to two-foot grid spacing, and increases repeatability with sensor position determination to within a few centimeters. The mobile light measurement system also increases safety by keeping test engineers out of roadways, and for the first time, makes practical the measurement of efficacy on location.
Typically efficacy is measured in the laboratory. Scotty allows measurement in the field. Field measurement allows researchers to measure light degradation over time without removing the fixture and shipping it back to the lab. EPRI typically measures this once a quarter. Field measurement allows researchers to determine performance, taking into account dirt buildup on the fixture.
Scotty has a number of features including:
Differential GPS accurate to within several centimeters
Precision light meter with photopic and scotopic measurements
Position and light meter data acquired at >3 Hz
Temperature and humidity sensor
On-board computer
Integration into project server for post processing
Key contact for the LED Street Lighting Demonstration is Tom Geist.
About EPRI
The Electric Power Research Institute, Inc. (EPRI, www.epri.com) conducts research and development relating to the generation, delivery and use of electricity for the benefit of the public. An independent, nonprofit organization, EPRI brings together experts from academia and industry as well as its own scientists and engineers to help address challenges in electricity generation, delivery and use, including health, safety and the environment. EPRI's members represent more than 90 percent of the electricity generated and delivered in the United States, and international participation extends to 40 countries. EPRI's principal offices and laboratories are located in Palo Alto, Calif.; Charlotte, N.C.; Knoxville, Tenn.; and Lenox, Mass.
