GROUP 9 - Wireless Drifter  
 

The Front View and Back View of the Drifter Circuit without the casing

 
 

The group at the Senior Design Fair

 
Overview:      
 

The wireless drifter is a device used to collect data in water current by monitoring it.  It works by interfacing various components such as sensors, a microcontroller, a GPS unit, and transceivers.  The sensor picks up the parameter in question to be researched and sends the data to the microcontroller.  The microcontroller translates the reading from voltage difference to a digital signal.  This binary data is sent to the wireless transceiver.  The data is then transmitted from the wireless transceiver to base station which is located some distance away.  This is where the data is collected and stored for further interpretation or research.  These components, the microcontroller, GPS unit, sensor, and wireless transceiver, once put together allow the wireless drifter to function as a unit.

 

 

Purpose & Requirements

     
 

The purpose of such a device is to allow researchers, scientists, or homeland defense specialists access data in a real time environment without having to make lengthy trips to collect readings across a wide area.  Requirements for the project are low cost, long lasting and having some disposable value after its useful life has expired.  Power consumption will need to be monitored and an appropriate power source will need to be determined, and the modularity of the sensors and other hardware needs to be designed and an appropriate case created accommodating these needs.

  
Goal:      
  The wireless drifter has been in development here at Stevens for a few years now.  For our senior design project this year, the group will add more features to the previous devices, as well as ironing out any remaining bugs in the system.  Some possible modifications to the wireless drifter are: change the wireless signal used to increase range and bandwidth by using a newer transceiver; making the sensor system modular to allow for different types of sensors to be used depending on the data needed; adding the capability to use different sensors than what is currently implemented; and upgrading the power supply to use solar power.  A rechargeable battery will be added in addition to the solar panel, so that during the night, the wireless drifter will utilize the stored energy of the rechargeable battery.  Changing the microcontroller that we will use allows for higher performance and also enables two way communications between the base station and the wireless drifter.    
Acknowledgement:      
 

The group would like to thank the following people for their help.

  • Our advisor, Prof. Yao; without him this project would not exist.  He has managed to keep us on track, as well as giving us useful advice for selecting our components and putting them together.
  • Stevens WISELAB, for allowing us to use the lab’s equipment and space to work on our project.
  • All the previous Senior Design groups that have worked on the Wireless Drifter.  Our work is based off all the hard work all of those who came before us.  Without work and documentation, our project would be much more difficult.
  

Critical Components:

      
 

Listed below are the critical components of the drifter, all parts have been acquired and are either implemented, or in process of being so. 

    • Microcontroller Development Kit - Rabbit RCM3100
    • Wireless Transceiver Development Kit  - Maxstream XStream Dev Kit, 900 MHz 9600 baud
    • GPS Unit - Rockwell Jupiter v230
    • Casing (from old design groups)
    • RS-232 to USB adapter cables
    • Low Dropout Voltage Regulators in 3.3V and 5V
    • 2mm Board Mount Connector 20 pin straight sockets
    • C-Grid Connector 16 pin headers
    •  12-bit 8 Channel A/D Converter
    • DIP Socket 16 pin for A/D converter
    • Sensors and other small components (from previous drifter projects), these include the light and temperature sensors. 
 

Functionality and Performance:

      
 

Overall, the functionality and performance are same as what we predicted in the Final Design Report.  The only changes we made are the sensors.  Due to resource constraint, we are only going to implement temperature and photoelectric (light) sensors.  If we have more time toward the end of project life cycle, we will implement additional sensors.  The wireless drifter is going to have following functions and expected performance.


Functions:

  • The drifter will have a built-in GPS with Google mapping capability.
  • The drifter will carry temperature and photoelectric sensors.
  • The drifter will be able to transmit data wirelessly over a distance of 20 miles.

Performance:

    • The drifter must be waterproof.
    • The power consumption of the drifter must be minimal, with a high longevity power source.
    • Keep the cost of the drifter low.
    • Wireless range must be long enough to maintain a stable connection.