University of Wisconsin-Madison Physical Sciences Lab

Archive for 2015

Teaching the Future

Thursday, December 17th, 2015

Back Row: Tyler Doering, Willis Perley
Front Row: Barry Shepherd, Michelle Halpert, Tyler Trickle

This past summer, PSL started an internship program with four UW Engineering students, and a student from Madison’s LaFollette High School. This internship program exposed the students to real world engineering, and the variety of projects PSL is working on. They worked on the Anode Plane Assembly for DUNE, a project for Princeton Plasma Physics Lab, as well as an ice drilling test facility that will be here at PSL.

PSL’s Darrell Hamilton teaching the interns metrology, performing precision measurement on a DUNE APA.

Barry and Michelle assist moving the APA frame.

From Many, One

Wednesday, July 22nd, 2015

UW-Madison’s Forest Products Lab contacted PSL with an interesting problem. The computer, which runs a Spex Fluorolog 2 Fluorescence Spectrometer, needed to be upgraded since it was 20 years old. Unfortunately, the card that talks to the spectrofluorometer inside the computer wasn’t compatible with modern PCs. PSL Electrical Engineer Dan Wahl created an instrument, called RetroSPEX, which translates signals to and from the spectrofluorometer into a standard USB port.

The left image is the side that connects to the spectrofluorometer, the right image is the USB connection.

In order to design the instrument, Dan needed to reverse engineer the connections, understand what needed to be controlled and how to control the components. Armed with that information, he was able to design:

“The RetroSPEX controller combines a Microprocessor + FPGA + ADC/DAC + High voltage power supplies into a compact form. The connectors on the back panel of the RetroSPEX match the cabling of the original instrument.”

The new and old computers, with the RetroSPEX instrument on the far right.

Once the instrument was designed, a text based application programming interface (API) was created to make the computer be able to issue command, through the RetroSPEX instrument. Since the API isn’t user friendly, James Luscher Engineering Services was hired by the Forest Products Lab to write a Python-based user interface.

A screenshot of the user interface.

This is a spectrum captured by the spectrofluorometer following the installation of the RetroSPEX unit.

FLAMe on the Water

Thursday, April 30th, 2015

PSL’s Terry Benson (right) holding the new FLAMe unit with UW Limnology’s Luke Loken holding the FLAMe prototype.

Professor Emily Stanley’s lab in the UW-Madison Center for Limnology, or the study of inland waters (lakes, rivers, streams, resevoirs, etc.), created a boat mounted water testing rig called FLAMe (Fast Limnology Automated Measurement). This device can test for a number of different parameters (including water pH, CO2 levels, and nitrates) while the boat is moving at speeds up to, and exceeding 25 mph.

Limnology approached PSL to make a number of improvements. Led by PSL mechanical engineer Terry Benson, the following changes were made:


  • more rugged
  • more secure
  • made more modular, to increase options of testing devices
  • easily adapt to more boats, and positions on the boat.

The FLAMe unit mocked up at PSL.

    The piping was switched from galvanized steel to stainless steel, which means:

  • Less contamination of the water being tested.
  • More adjustability
  • More modular, to increase options of testing devices
    Overall, the unit improved:

  • Useability
  • More options due to the modularity of the unit.
  • Ruggedness
  • Made it easier to work on in the field.
  • Aesthetics were improved greatly!

Later, the rig was tested in Limnology’s testing boat, and the test went very well.

A close-up of the clamp.

This project is a result of PSL’s Pro Bono program, which helps UW researchers to design and build research instrumentation for a reduced, or no cost.

Water Counter: Counting on Upgrades

Thursday, February 26th, 2015

Inside of the box, with the new circuit board installed.

This box is one of four units supplied by the Wisconsin Energy Institute. The unit counted the presence of water by responding to a conductive path between an AC signal generator and rectifier circuit. The box was originally designed and constructed by a graduate student, however, the units never worked reliably.

Detail of the old circuit board.

PSL was asked to fix them, and a number of methods were explored. The units were upgraded to Arduino circuit boards, which offer reliability, a large online support community, and a number of upgrade paths. Some possible upgrade paths are wireless control, and Bluetooth monitoring.

A completed box ready for delivery.