Rain Gauge Retrofit

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Team Rain Men
Sponsors USDA Forestry Service. Main contact: Pete Robichaud, probichaud@fs.fed.us
Team Name Rain Men
Duration Fall - Spring 2014/2015
Faculty Advisors
  • Kevin Krueger
Team Members
  • Alec Harrison
  • Nick Kirby
  • Mike Kaminski
  • Peter Frankenfield

Current rain gauges store data in physical form, requiring an individual to laboriously convert data to electronic form so that it can be stored and analyzed by a computer. The rain gauge retrofit entails modifying current rain gauges throughout the northwest to store data in electronic form from the start, saving time and money for the US forest service.

Problem Definition


Why make a conversion for rain gauges?

Currently, each rain gauge requires an individual to laboriously convert data on a piece of paper to data in programs such as excel. There are many of these gauges throughout the world, and most still rely on the older designs utilizing paper rolls. Converting the initial data collection to electronic form could save on quite a bit of man-hours, allowing the forest service to use those man-hours elsewhere.

Current methods

There are many small variations in design, but they all work on one basic premise: physical movement of an actuator arm, combined with an internal tension spring. Calibration is relatively simple: the recording paper is marked to give reference numbers regarding rainfall in fractions of an inch, and the system is balanced using various sets of weights until the actuator arm accurately reflects real rainfall amount.


2014 Raingauge specifications.png


Working Retrofitted Rain Gauge

Development to date:

  • Transferring Displacement to Potentiometer
We have completed our final prototype of this system, found below in Project Learning
  • Potentiometer
We have bought, tested, and verified that our current potentiometer meets all specifications required by our project. Details can be found in Project Learning.
  • Data Logger
We have a datalogger that meets all our specifications, and is already configured with arduino software to give us real-time data on voltage and rainfall levels
  • Energy Storage
Preliminary analysis on energy needs has already been performed; batteries and support equipment have been acquired. Details can be found in the Project Learning section.
  • Electrical Component Housing Unit
The housing unit is complete and has met our specifications. Details of this system can be found below, in Project Learning.

3D modeled rain gauge with retrofit

In Project Learning we have the results of our 3D modeling, which clearly shows that plenty of room exists within current rain gauges for our retrofit design.

Operation diagrams

Both CFD and DFD diagrams are finished and can be seen in Project Learning.
Wiring Diagram

Potentiometer & data logger calibrations

Calibration is performed using a switch located on the housing unit, and is done on-site.

User Manual

The user manual is currently composed of electrical and mechanical portions.
Electrical Engineering Manual
Mechanical Engineering Manual

Project Learning

Electrical Engineering

Noise Analysis
Noise analysis was performed on multiple potentiometers to determine viability.
Analysis and Report
Validating Rotary Potentiometer
Having selected the rotary potentiometer to move forward with design we needed to validate its range of operation and maximize the useable range.
Analysis and Report
Power Analysis
In order to select a usable power system the current of the system must be measured and minimized. Experiments were performed and future experiments are planned.
Analysis and Report
Operation/Control Diagrams
2014 RainGauge DFD.jpg
2014 RainGauge CFD.jpg
2014 RainGauge buttonCFD.jpg

Mechanical Engineering

Housing Unit Development
Initial Housing Unit
Design Iteration 2-12-2015
Design Iteration 2-26-2015
Design Iteration 3-8-2015
Design Iteration 3-30-2015
Design Iteration 4-1-2015
Design Iteration 4-2-2015
Design Iteration 4-16-2015
Design Iteration 4-21-2015
Design Iteration 4-22-2015
Bracket and Gasket Development
Bracket Iteration 4-7-2015
Bracket Design 4-13-2015
Gasket Punch Iteration 4-22-2015
Gasket Punch Design 4-24-2015
Table 1: Design Features
2015 rain gauge housing unit2.png
Housing Unit Features
A) These soft curves are added throughout the box to distribute internal stresses more evenly, preventing the abs print from splitting.
B) 'mouse ears' are added to prevent the corners from curling while the 3D print is in progress
C) a flat surface for application of foam neoprene, to ensure a watertight seal.
D) Various mounting points for: a datalogger, on/off switch, calibration button, temperature sensor, and potentiometer
E) .25 inch holes are to provide room for aluminum thread inserts, which are installed by melting the surrounding plastic
F) Mounting channels on the bottom give a solid support structure, with hexagonal slots gripping locknuts so only one tool is needed for mounting the project box to the rain gauge.
2015 rain gauge l-arm assembly2.png
L-Arm Assembly Features
A) This is the point of contact between the assembly and the existing rain gauge.
B) The gear rack, which interfaces with the gearbox assembly
C) Aluminum beam, used to stiffen the geartrain
D) Custom brackets designed to keep the gear rack oriented in a vertical position
2015 rain gauge gearbox assembly2.png
Geartrain Features
A) The pinion that rotates from the L-arm Assemblie’s Gear rack
B) The spur gear that rotates with gear A
C) The final pinion gear, directly connected with our rotary potentiometer. This is near the heart of the change from mechanical to electrical systems.
D) The gearbox shaft, designed to be immobile. Note that there is a sleeve bushing underneath gear A and B.
2015 rain gauge full assembly2.png
Full Assembly Features
To the left is the Mockup of our full conversion sitting at the base of the original rain gauge enclosure.

Choosing the right box
After modifying a variety of off the shelf project boxes it was found 3D printing to be the best option. A cost analysis was performed to validate the printer purchase and printer selection.
Cost analyis/ Final printer

Team Information

2014 RainGauge Portrait Nick Kirby.jpg
Nick Kirby Interests: Solid modeling, statistical analysis, mechanics of materials

Life Goals: government work through the EPA or USDA

Mechanical Engineering Student
Hometown: Meridian, Idaho
Email: kirb5074@vandals.uidaho.edu
2014 RainGauge Portrait Mike Kaminski.jpg
Mike Kaminski I'm a senior studying Electrical Engineering focusing on microelectronic fabrication and design. I've completed an internship with Micron working in their system compatibility group helping develop DRAM test procedures. After graduation I'm pursuing a job in the field of microelectronics.
Electrical Engineering Student
Hometown: Coeur d'Alene, Idaho
Email: skaminski@vandals.uidaho.edu
2014 RainGauge Portrait Alec Harrison.jpg
Alec Harrison Interests: Using natural restoration techniques to help improve fish habitat, especially in highly eroded areas.

Life Goals: Obtaining a career pertaining to wildlife conservation, dealing with issues of drought and water conservation in the western united states

Biological Systems Engineering Student
Hometown: Boise, Idaho
Email: harr7706@vandals.uidaho.edu
2014 RainGauge Portrait Peter Frankenfield.jpg
Peter Frankenfield Interests: Fatigue Fracture Analysis, Solid Modeling, Mechanics

Life Goals: To contribute to society while loving what I do

Mechanical Engineering Student
Hometown: Spokane, Washington
Email: fran7684@vandals.uidaho.edu

Document Archive

Rain Gauge Contract
Rain Gauge Design Review Slides
Rain Gauge Action Items