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Similar a 2016-10-11 IoT Presentation V4
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2016-10-11 IoT Presentation V4
- 1. Pressure Study Gooseberry Island Causeway An IoT Research Project (sort of)
- 2. Agenda • Problem Statement – Video of the area • Thesis • Objective • Approach – Hardware – Software – Bug Fixes & Enhancements – Physical Issues • Tests • Issues and Fixes • Experiment Results • Conclusion • Observations and Opportunities
- 3. Problems Sandbars Algae Blooms Beach Stones
- 5. What’s New? Gooseberry Island Causeway Tower
- 6. Currents and wave action that once flowed over the tombolo … … began circulating in an eddy. BEFORE AFTER Thesis: The Change
- 7. Thesis: The Result Sand is transported toward the harbor by new Westerly current Sand is deposited in the harbor Nitrogen comes out of the river with every tide but circulates back in
- 8. Thesis: The Fix Equilibrium is restored and sand begins accumulating again The harbor is no longer threatened by sandbars Nitrogen flushes more thoroughly with each tide cycle Remove the causeway
- 9. Eddy currents are the result of a textbook “groyne” GROYNE GROYNE Source: Yossef 2005
- 10. Opposition In 1997, the Department of Environmental Management commissioned a study that concluded the causeway has no appreciable environmental impact.
- 11. Objective Cast doubt on the 1997 study and compel the Department of Environmental Management to re-examine impact of the causeway.
- 12. Objective Would water flow if there was no causeway? - in other words - Is the water level higher on one side than the other creating the potential for flow? Height West Height East
- 13. Approach Using survey tools, physically measure the height of the two sides and calculate the difference. Impractical to collect measurements over days and difficult at night.
- 14. Approach A sensor could measure up from the bottom … but how? Water pressure
- 15. Approach But the bottom is not the same on both sides, one side is going to be lower than the other. How would we know the offset? Combine approaches?
- 16. Approach Collect data from sensors over time.
- 17. Approach Normalize by the drop initial depth
- 18. Approach Use a single reading at a recorded date/time to align signals
- 19. Device Requirements • Read Pressure up to 25 feet under water • Accurate to less than 1 inch • Submersible • Runs on battery for several days • Inexpensive • Small
- 20. COTS Hardware Components BMP180 Pressure range: 300 ... 1100hPa (-34 feet below sea level, salt water) Low power: 5µA at 1 sample / sec. in standard mode Low noise: 0.02hPa (0.17m) advanced resolution mode DS3231 Real Time Clock Accurate to within 1 second per year Button battery maintains time between uses Low power 32u4 Adalogger ATmega32u4 @ 8MHz 2K RAM MicroSD card holder Built in 100mA lipoly charger
- 21. Wiring AdaFruit “Feather” “Wing” bus Power I2C Data Prototype
- 22. Software • Include Libraries – #include <SD.h> – #include "RTClib.h" – #include <Adafruit_Sensor.h> – #include <Adafruit_BMP085_U.h> • Set-up – Initialize pressure sensor – Initialize SD card – Confirm clock working – Create log file • Loop – Read Sensor – Read time – Write entry – Sleep 60 seconds (minus a few instruction cycles) Code: https://github.com/dsprogis/Pressure-Sensor-1.0-build-4
- 23. Triple Bagged, Weighted Bucket
- 24. Test 1: Does it work? {"date": "2016-07-15T22:19:29", "pressure_hPa": "1013.78", "temperature_C": "28.00", "altitude_meters": "-4.41"} {"date": "2016-07-15T22:20:29", "pressure_hPa": "1013.75", "temperature_C": "28.00", "altitude_meters": "-4.16"} {"date": "2016-07-15T22:21:29", "pressure_hPa": "1014.84", "temperature_C": "27.90", "altitude_meters": "-13.23"} {"date": "2016-07-15T22:22:29", "pressure_hPa": "1151.47", "temperature_C": "27.90", "altitude_meters": "-1092.00"} {"date": "2016-07-15T22:23:30", "pressure_hPa": "1151.21", "temperature_C": "27.80", "altitude_meters": "-1090.05"} {"date": "2016-07-15T22:24:30", "pressure_hPa": "1150.85", "temperature_C": "27.70", "altitude_meters": "-1087.34"} ... Yes
- 25. For how long? 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 0 20 40 60 80 100 120 140 7/16/16 0:00 7/17/16 0:00 7/18/16 0:00 7/19/16 0:00 7/20/16 0:00 7/21/16 0:00 7/22/16 0:00 7/23/16 0:00 7/24/16 0:00 Temp (F) Depth (ft) About a week
- 26. Device Calibration? 1150 1170 1190 1210 1230 1250 1270 1290 1 216 431 646 861 1076 1291 1506 1721 1936 2151 2366 2581 2796 3011 3226 3441 3656 3871 4086 4301 4516 4731 4946 5161 5376 5591 5806 6021 6236 6451 6666 6881 7096 7311 7526 7741 7956 8171 8386 8601 8816 9031 9246 9461 9676 hPa 1 hPa 2 hPa 3 Readings deviate by 0.002-0.004 inches (salt water) Readings deviate by ~0.5C Aligned
- 27. Requirements (review) Read Pressure up to 25 feet under water Accurate to less than 1 inch Submersible Runs on battery for several days Inexpensive Small Units are calibrated
- 28. Issues One device went bad – not sure why. Spider Crab found in one container – outer bag was punctured Units are not reporting on exactly same interval – adjusted in Excel but very time consuming! time
- 29. Software/Hardware Enhancement • Fix time drift – Hardware: • Jump 1Hz Square Wave Signal to readable pin (yellow cable, SQW to A2) – Software: • Decrement counter on rising signal (A2) • Log data when counter = 0 – Reset counter to 60 (or whatever I want) A2 = I Hz A2
- 30. Additional Software Enhancements • Switch from JSON to CSV – more convenient for Excel • Added Device ID to filename – easier to keep track • Added Date to file in OS – easier for managing archive
- 31. Deployed Devices at Causeway
- 34. Conclusion • West side averages 6” higher than East side • Peaks about 12” per tide cycle • Is level or slightly below per tide cycle • Causeway holding back 6” inches of water across a 900 feet. • Holding back or redirecting this much potential energy is certain to have an appreciable environmental impact. QED
- 35. Objective The 1997 study is wrong. The causeway DOES HAVE an appreciable environmental impact.
- 37. Tide/Temp Offset Water temp reached it’s low 90 min after tide reached low and began coming in. Why? How can we use this information?
- 39. What’s going on with this double hump? First it gets warmer, then cooler, then warmer again?
- 41. Pressure Study Gooseberry Island Causeway David Sprogis dsprogis@gmail.com
Notas del editor
- This presentation is a story about an environmental problem. It’s about evidence gathering and case building using an Arduino-base sensor. I refer to IoT because the device benefits from many of the COTS devices that have become available thanks to the IoT revolution.
- Over the last five decades, three problems have emerged in the Westport shoreline and waterways. Sandbars have developed in the harbor requiring the Army Corps of Engineers to dredge. Algae blooms are occurring regularly and tests show unexpectedly high levels of nitrogen. The once sandy beach is becoming a stony beach.
- What changed? During WWII, the Army Corps of Engineers constructed submarine lookout towers on Gooseberry Island. For enable access, they Corps created the causeway.
- So here’s the problem … Every time residents try to discuss the impact of the causeway with the State, the State deflects the conversation with a study that concludes that the causeway has no appreciable environmental impact. The study was conducted by a well-known oceanographic team out of the Woods Hole Oceanographic Institution
- The objective of this study is to cast doubt on the study by showing that the causeway is interrupting a current and either holding it back or redirecting it as we contend.
- The Approach is to use pressure sensors to collect readings over a week. Then. we tie the readings to a reference reading taken through a single reading using traditional survey equipment.
- AdaFruit calls their processor board a “Feather” and they call their shields “Wings”. Metaphorically, I think they have it backwards but you get the idea – the components are designed to be soldered straight-through – effectively creating a bus. The exception was the sensor which had to be accommodated differently, but with only 4 wires. SDA and SCL were connected on pins, the black and red supply power. The yellow cable pictured came later – I will explain it later.
- Device reports pressure in hPa = hectopascal (100 pascals) = one millibar. Sea level at 45deg Latitude is generally accepted to average 1000 millibars, or 1 ATM. We are at about 42deg Latitude but daily changes in weather are more likely responsible for the value of 1013.78 when I dropped the devices.
- Four devices were dropped in the water, three collected data and the fourth collected no data. The three signals are plotted above and are highly synchronized – very good news! Pressure readings are aligned to within thousandths of an inch. Temperature readings (which we don’t really need) are aligned to within half degree C.
- There were three issues One of the devices failed – all three components tested bad – not sure why – NO ACTION A Spider Crab got into one of the containers and punctured an outer bag – KEEP TRIPLE BAGGING The microprocessors seem to be executing identical instructions at slightly different processor speeds which meant adding “catch-up” rows in analysis – FIX IN SOFTWARE/HARDWARE
- Because the real time clock is much more accurate than the crystal driving the microprocessor, using it to guide reading interval ensures alignment. Jump the RTC’s 1Hz signal to a readable pin. Because A2 is right beside it, why not? What would have been a better way to do this? (Set an interrupt) I deferred in the interest of time. This is called “technical debt” because it should be documented as a bug/enhancement then prioritized for the future.
- What’s going on in the third and fourth cycles? (Wind direction changed)
- We know that the water level on both sides goes up and down but to simplify the visualization, I have represented the relative differential on one side. The West side, Rhode Island Sound side, averages about 6” inches higher than the East side, Buzzards Bay. The causeway is holding back and average of 6” inches of water across a 900 foot span. Holding back or redirecting this much potential energy is certain to have an appreciable environmental impact.
- If we placed sensors along the beach, could we detect the circulation of warm water – warm water carrying nitrogen that should be flushed but is instead heading back into the river.
- Can we learn anything from the temperature across the causeway? Unit 1 is on the West side, Unit 3 is on the East side. Wind was blowing out of the South East from 7/31 to 8/2 then return to a prevailing South West wind after. Thus, it appears that Buzzards Bay is warmer than Rhode Island Sound on a South East wind but more typically, Rhode Island Sound is warmer. Temperature fluctuations are greater on the Rhode Island Sound Side (blue). We know that the Gulf Stream temps do not fluctuate this much therefore we can deduce that this warm water is coming out of the river. Judging by the location of the sensor, this warm water has no other place to go than back into the river.
- This presentation is a story about an environmental problem. It’s about evidence gathering and case building using an Arduino-base sensor. I refer to IoT because the device benefits from many of the COTS devices that have become available thanks to the IoT revolution.