Introduction: Low Altitude Environmental Monitoring With an Arduino Based Weather Instrument and Aeropod Remote Sensing Platform
Students at New Lothrop High School in Michigan have worked together to build a low altitude remote sensing platform called an "Aeropod" and outfitted it with an "Arduino" based weather instrument to gather atmospheric and other environmental data up to a height of 500 feet above ground level. The weather instrument is mounted on the Aeropod then lifted into the atmosphere with a tethered lifting device (a kite). This project integrates engineering and design practices into existing high school Earth Science units on Meteorology and Remote Sensing to support science classroom practices intended to fulfill Next Generation Science Standards.
This project required two phases... Construction and Licensing and then Training and Data Collection.
The inital Construction and Licensing phase required a few months in real time. The four main tasks that needed to be accomplished for construction and licensing are:
- Purchase components and build a small "Arduino" based weather instrument (2 weeks to 2 months, depending on experience). Construction of the weather instrument was accomplished after school during the winter of 2014-2015 during Science Club meetings.
- Purchase a suitable lifting device (kite) and supplies (2 weeks). The Kite was purchased from a commercial vendor (Into the Wind) and required tying a few barrel swivels to the kite line and was quickly "ready to fly" after receipt.
- Obtain an Aeropod License (2 to 3 months). The Aeropod design is patented and can be licensed free of charge for educational use from NASA. The license was obtained from NASA Goddard Space Flight Center engineer Geoff Bland, creator of the AEROKATS program. Geoff designs low altitude custom remote sensing platforms, called Aeropods, for agricultural and environmental research purposes.
- Build an Aeropod (3 days). Construction of the Aeropod was accomplished during regular class time with the assistance of our school industrial arts teacher.
The Training and Data Collection was accomplished during class in about one week real time and consisted of two main tasks:
- Practice deploying and retrieving the Kite and Aeropod with "dummy" instrument package (2 days)
- Perform remote sensing and download data for analysis (about an hour, repeated as often as desired)
We wish to recognize the following people that provided support and guidance during this project:
- Paul Buchtel, New Lothrop High School, Industrial Arts Department
- Jonathan Knieper, New Lothrop Alumnus and Electrical Engineering Student at Saginaw Valley State University
- Dave Bydlowski and Andy Henry, The ICCARS Project, Wayne County Regional Education Services Agency
- Geoff Bland Wallops Field Support Office and Darryl Mitchell Innovative Technology Partnerships Office, NASA Goddard Space Flight Center
Step 1: Choosing a Remote Sensing Platform and Instrument
Students in our school were exposed to the Arduino open-source electronics platform for electronics design during a guest lecture presentation in May of 2014. In discussion after the presentation we were inspired to build an Arduino based weather instrument that we could use to obtain meteorological soundings of the atmosphere. After deciding to build an instrument we had to choose a remote sensing platform to lift our instrument above the Earth. We considered two types of remote sensing platforms...
- A tethered lifting device (kite or balloon) with a dropline used to suspend an aerodynamic platform (an Aeropod) on which we could mount our weather instrument.
- An unmanned aerial vehicle (like a quad copter) on which we could directly mount our weather instrument.
We chose the tethered device and aeropod because the concept has been well documented on the Investigating Climate Change and Remote Sensing (ICCARS - pronounced "ikarus") website published by the Wayne County, Michigan Regional Education Services Agency. The resources at this site included images, videos, lesson plans, documents, and tutorials which we could study to create a successful remote sensing platform. Of particular usefulness to us were the VIDEO Links on the ICCARS website which showed us construction and assembly tips for creating Aeropods and Kite recommendations.
Our project seemed unique from previous ICCARS projects because rather than using commercially available detectors (cameras or a Kestrel weather and environmental meter) we intended to build a weather instrument to be used for environmental monitoring. Building our own instrument promoted enthusiasm in our students by meeting their desire to learn more about electronics and computer programming.
Step 2: Assembling the Weather Instrument
Our first step in creating the weather instrument was to purchase the hardware. We purchased Arduino circuit boards and associated components from SparkFun Electronics. The SparkFun website tutorials and online support staff answered most of our technical questions. The components purchased were:
- Sparkfun RedBoard DEV-12757 (Sparkfun's version of an Arduino Uno R3)
- Sparkfun WeatherShield DEV-12081 (Barometric Pressure, Relative Humidity, Luminosity, and Temperature)
- Sparkfun Stackable Header Kit - R3 PRT-11417 (solder to WeatherShield for mounting on the RedBoard)
- Sparkfun OpenLog DEV-09530 (open source micro SD serial datalogger to store data during sampling)
Other necessary materials were available in the science club part bins or were purchased from Radio Shack:
- 9V Battery (to power the instrument during remote sensing)
- Center-positive barrel connector with an outer diameter of 5.5mm and inner diameter of 2.1mm connected to a 9V battery Snap Cap (may have to buy cap and connecter separately - solder red wire on center pin)
- USB 2.0 type A to Mini-B 5-pin cable (necessary for downloading operating instructions from a PC to the weather instrument)
- USB 2.0 micro SD Card Reader
- Four ~5cm long 20-22 gauge solid copper wires (these are needed to connect the OpenLog datalogger to the weather instrument)
- 25 Watt soldering iron and flux core solder (for soldering Headers and OpenLog connections)
We were careful to read and follow the instructions and videos on the Sparkfun website:
We found that assembling the Arduino hardware was easy! We assembled the instrument in four steps...
- Solder Headers on the WeatherShield (the SparkFun soldering video has helpful soldering tips)
- Plug the WeatherShield with Headers into the RedBoard
- Solder leads to the OpenLog and plug the leads into the appropriate Weather Shield Headers
- Solder a Barrel Connecter to 9V Snap Cap so we can connect our 9V battery to power the instrument
After following these four steps the weather instrument was assembled and ready for programming.
Step 3: Programming the Weather Instrument
Once the instrument was assembled we had to upload code so the instrument would collect and store data. The tasks needed for programming the instrument inlcude downloading the Arduino Software Program to our desktop computer, obtaining sample code from the SparkFun website, and then uploading the code to the weather instrument.
These tasks, in detailed order are...
- View the Sparkfun WeatherShield Hookup Guide to learn about connecting and programming the WeatherShield. The Sparkfun site suggests loading their sample code to the WeatherShield.
- Download the open source Arduino Software to our desktop computer and then save the sample "sketch" (Arduino files are called sketches) provided by SparkFun to the Arduino library on our desktop computer.
- Connect the weather instrument to our desktop computer with the USB/mini B cable.
- Open the Arduino program and use commands from the dropdown menu at the top of progam screen select the appropriate COM port (we used COM 9) to communicate via the USB.
- Open the Arduino sketch from the "Files" menu of the Arduino program.
- Select Upload file from the dropdown menu on the Arduino program. As soon as the program was uploaded the lights on the weather instrument and OpenLog began blinking during each data acquisition timepoint.
- Finally we verified that data was being collected by opening the serial output monitor in the Arduino program and observed the output of our now functional WeatherShield!
After viewing the data generated by our weather instrument using the Sample Code we decided to inspect and then modify the code. We removed code lines for sensors not installed on our instrument and changed the data collection rate to 1 point every 10 seconds (mostly a trial and error editing process). The file attached to this step documents our revised code.
Many thanks go to Jonathan Knieper, a New Lothrop alumnus who helped us learn to navigate through the Arduino software and programming steps required at this stage of the project.
Step 4: Aeropod Design Specifications
After assembling our weather instrument we found it had a mass of about 90 grams and dimensions of about 7 cm x 7 cm x 2 cm. We consulted with Mr. Buchtel, our Industrial Arts teacher to identify materials and design specifications for an Aeropod capable of carrying this payload. We used materials readily available in our woodshop and "reverse engineered" Aeropod specifications based on an Air Column Profiler Assembly video found on the ICCARS website. Important design parameters we identified while watching the video were length of the Boom, Instrument Mounting position, rear Stabilizer size, and Pitch (fore to aft attitude). Important general guidelines were...
- The length of the Boom (the "fuselage" of the Aeropd) should be about 60cm in order to accomodate a 90g payload with the ~7cm square footprint.
- The Instrument Mounting Platform at the front of the boom should be mounted about 9cm below the centerline of the Boom. We considered that location of the instrument mounting platform below the centerline could aid in stability during flight.
- The Horizontal and Vertical Stabilizers at the tail of the Boom should be flat and need to be secure in flight. We estimated that they should extend about 10 to 15cm from the top and sides of the Boom with a chord length (distance from leading to trailing edge) of 6 to 10cm.
- The nose of the Aeropd should be slightly below the tail (~2 cm) when suspended and no wind is blowing.
We worked in multiple project teams, simultaneously experimenting with different materials and stabilizer dimensions. After constructing four Aeropds we tested them for stability in flight with a "dummy payload" of 90 grams and chose the Aeropod with the most stable flight characteristics for use during subsequent flights.
The dimesions of the Aeropod which flew best are described below (see the PDF parts diagram below for details)...
- Boom (our Boom was made of Luan): 8mm x 8mm x 64.5 cm long
- Instrument Platform: 12.5cm long x 9cm wide x 0.5 cm thick made of lightweight plywood
mounted at front of Aeropod, suspended 9 cm below and centered on the boom, parallel with horizontal plane.
- Boom/Instrument Platform mounting carriage (mounted vertically with long axis parallel to the Boom - connects Instrument Platform to Boom) 12.5cm x 9cm x 0.5 cm - made of lightweight plywood. The mounting carriage has a 9cm x 3cm recess along the bottom to create a cavity for the weather instrument.
- Horizontal Stabilizer (made from styrofoam meat and produce packing trays) 21cm x 9cm x 1.5mm thick
- Vertical Stabilizer (made from styrofoam meat and produce packing trays) 11cm x 11.5cm x 1.5mm thick
- Mounting Fulcrum - called a PYLON in ICCARS videos was made from the 9cm x 3cm piece of scrap material that was cut from the mounting carriage
Step 5: Materials for Aeropod Construction
Most of our construction materials were found in the scrap bin in our woodshop. We cut wood pieces with a scroll saw and foam pieces with a hot wire. We bought various types of glue, including cyanoacrylate (superglue) Gorilla Glue, and Gorilla Superglue, along with zip ties. All pieces were dry fit before gluing so they could be assembled easily. Some teams tried foam for the fins, others used cardboard. The regular superglue melted the styrofoam and the regular Gorilla glue took too long to set. We had our best success assembling all materials with Gorilla Superglue.
- (1) Lightweight but strong wood (we used Luan) 66.5 cm long 8mm wide x 8mm high
- Carriage, Instrument Platform and Fulcrum
(2) Lightweight plywood rectangles approximately 12.5cm long x 9cm wide x 0.5 cm thick
(waste from Carriage is used for the Pylon)
- Horizontal and Vertical Stabilizers
(2) Styrofoam meat and produce packing trays
- Nylon Cable Ties
Step 6: Aeropod Construction Notes
We constructed four different Aeropods based on the design specifications described in step four of this instructable and the motto "Let's fail as fast as we can!". Our goal was to create multiple variations of prototype Aeropods within two days, and identify critical flaws quickly.
Before construction began we once again viewed the ICCARS construction videos.
We divided into four teams and started assembling pieces to create devices that looked like those we saw in the videos. We glued wood and foam, but regular superglue did not work with the foam fins (it melted the foam).
A rectangular space was cut into the carriage to make room for the weather instrument. The battery was secured to the instrument platform with Gorilla Superlgue but the weather instrument was secured to the mounting platform with cable ties. Each of the four teams assembled an aeropods, making sure to find the center of mass when positioning their Pylons.
Our completed Aeropod weighed about 100 grams, and when fitted with instrument and battery payload weighed about 190 grams.
The kite used to lift the Aeropod was a 7 foot Levitation Delta Kite and 75lb dacron Kite Line and accessories, as recommended on the ICCARS website. All Kite connections were mades as described in the Kite, Line and Aeropod Connections diagram on the ICCARS website.
Step 7: Practice Deploying and Retrieving Aeropods
- Important: Anyone handling the kite string must wear gloves for safety.
- Winds need to be between 5 - 15 Miles per hour to fly our 7 foot kite.
-Slowly unwrap the string for the spool to let the kite lift into the sky.
- When the kite gets 250 feet high attach the aeropod to the barrel swivel on the Aeropod dropline.
-Let the aeropod lift about 500 feet into the air, and after allowing time for data collection begin to pull the the string down and rewind it onto the spool.
Be careful not to allow kite line to unwind and pile up in heap. We spent a lot of time untangling knots before we learned to always keep our line wrapped neatly on a spool!