UVIC Group #12

 

Self Powered

Wind Sensor

Sponsored by: AXYS Technologies and Environmental Systems

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PROJECT DESCRIPTION

PROJECT PROGRESS NEWS AND EVENTS DOCUMENTATION CONTACT US

Upcoming Events and Deadlines

January 12th, 2005

  • First Class Meeting, Elliot 062, 6 - 7pm. Deadline for submission of approved project.

January 17th, 2005

  • Progress Report #1 is due.

March 2nd, 2005

  • Midterm Review Meeting, Elliot 062, 6 - 7pm.

March 7th, 2005

  • Progress Report #2 is due.

April 1st, 2005

  • Poster Presentation and Project Demonstration       4pm Engineering Building Lobby.

April 8th, 2005

  • Final Report and Web design is to be completed.

Project Progress

This section of the website is split up into eight half month sections

Jan 01 - Jan 16, 2005

Made our group of three, and decided which project we were going to tackle.  We made a project proposal and a technical specification for both UVIC and our Company Sponsor AXYS Environmental Systems.  Met with Reo Phillips from AXYS to discuss the project and to "kick-off" the project.  The first project progress report was made, and can be seen here as well as the project proposal and the technical specification.

Jan 17 - Jan 31, 2005

Met with and got approval from Camosun College to use their wind tunnel to test the sensor, and to use their lab to test and build our project.  In order to achieve max output power, the resistance of the load must equal the internal resistance of the sensor. The internal resistance of the sensor was on the nameplate, and measured to be approximately 2000 ohms. The range of speed illustrated below is for average wind speeds in the Victoria region, with the upper value representing a value around the 60km/h mark. The sensor would produce sufficient amounts of power, if a hurricane were constantly blowing, creating a rpm of around 9000.  Unfortunately the outcome of the testing revealed that the sensor couldn't provide sufficient power.  The testing results achieved for the sensor can be seen below and it's easily seen that there just isn't enough power. 

To see some testing pictures click here.

Feb 01 - Feb 15, 2005

Thorough investigation went into trying to see if the sensor could be used, and the website started to be constructed.

Feb 16 - Feb 28, 2005

Thorough investigation went into trying to see if the sensor could be used, and the website started to be constructed.

Mar 01 - Mar 15, 2005

After examining every possible idea that came to BSS2, it was concluded that the project couldn't be done, and an alternate form of energy had to be investigated.  After much research BSS2 concluded and presented to UVIC and AXYS that solar power is industry standard, and would be the best solution for this situation.  After receiving approval, BSS2 had to really pick up the slack, as we had just over one month until the project had to be finished.  The first step of the design for the charging circuit for solar power was to pick and purchase a battery.  The biggest load needed to complete the wireless design is the transceiver, which needs 25mA to transmit once every minute.  We decided that a good safety factor to use, would be to use half of the current draw by the transceiver as a continuous one.  This would implies that we need 12.5mA for 1 hour.  We designed the system to run solely on battery power for 10 hours which would make the battery needed a 120mA hour battery.  The biggest battery we could find in equal physical size to a 120ma hour battery was a 140mA hour battery.  To see a data sheet for the battery click here.  We were choosing between Lithium Ion, Nickel Metal Hydride, and Nickel Cadmium, and chose to go with Nickel Metal Hydride.  Lithium Ion batteries cannot be obtained unless you go through rigorous approval steps for the charging circuit, as they will combust if they are operated at voltage levels lower than a certain potential, so for safety reasons primarily the Lithium Ion battery was not chosen.  The  Nickel Cadmium battery suffers from memory issues, and they cannot be constantly topped off.  If they are constantly topped off then their lifespan will rapidly deteriorate and the amp hour rating of the battery will decrease.  In order to obtain the operating temperatures needed by AXYS, a military grade battery would have to be purchased, which costs well over 200 dollars.  The idea behind this project was to get it working, if it has to be placed in such an extreme environment then the battery we chose can simply be replaced with a military grade one and the charging circuitry will not change. 

Progress report #2 was due during this period and therefore it was created, submitted and can be seen here.

Mar 16 - Mar 31, 2005

After reviewing some of Texas Instruments charging chips, BSS2 picked one that had very high efficient, and that could be used to charge all three types of rechargeable batteries with minimal modifications.  A circuit came with the chip to show all the connections needed.  We now need to figure out what we need in the circuit, and what we don't need, as all of the stuff implemented on the circuit had to altered to suit our application and some of it was unnecessary.  To see the data sheet for the charging chip used click here.

The voltage needed by the wireless crew (+5Vdc, -5Vdc, +3.3Vdc) is on either side of the battery  potential, and the voltage needed by the charging system is less than the output from the solar panel.  To adjust the voltage levels, the solar panel input and the battery output are fed into buck and boost regulators respectively to get the necessary levels.  To see the data sheet for the regulators used click here.   

The output of the charging circuit after the boost regulator is +5Vdc.  In order to achieve the -5Vdc, a charge pump had to be introduced into the system.  A charge pump is essentially a DC-DC converter that steps up voltages using capacitors, and also make a negative bus available.  Charge Pumps feature low noise and their efficiency is comparable to that of switching regulators.  To see the data sheet for the charge pump used click here.

The charging circuit is designed, and the components are ordered from Texas Instruments.  The components arrived, and the circuit was built and tested and after some "tweaking" concluded to be in good working order.  Click here to see a schematic of the entire system.

To see some pictures of the board testing click here.

After ensuring the circuit was how we wanted it, the next step was making the printed circuit board again using Camosun Colleges facilities.  First using a program called DXP we inserted our schematic and designed a layout for all the components we needed.  This program made a file that located all the traces and holes required.  The file was then input into the PCB printer program and the board was milled to the specific dimensions and tolerances required.  The next step was to manually solder all 45 components and 35 via's onto the board.  This step was extremely time consuming as the board was 60mm by 35mm and there wasn't much room for error.  Unfortunately after spending hours soldering and making the PCB it didn't work the way it was expected, and BSS2 couldn't find the error as we simply ran out of time.  We believe that there was a cracked trace somewhere on the board.  Luckily we still have the circuit on the breadboard for the project demonstration.  To see pictures of, the PCB printer click here, the breadboard to PCB pictures click here.

The project is done to the best of our ability, and the poster has been completed.  Everything is looking good, and will be completed on time and ready for demo day!!

Apr 01 - Apr 15, 2005

Poster presentation day went great, our project worked well, and our poster looked great.  There were a lot of people asking questions and looking at all the projects.  Our sponsor from AXYS Environmental Systems, Reo Phillips showed up, and for the first time saw the results we made for him.  He was happy with the results, so BSS2 was happy with their project!!

The project report and the website are finished and will all be submitted on time.  The only thing left to do is have one last project meeting at the local watering hole to celebrate a job well done!!

 

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