Problem Statement
Jarpe
Data Solutions approached our capstone team. Our given project was to
implement a two-way radio communication system. This system will
transmit seismic data from any particular unit deployed in
the field to a central data retrieval unit. The current system in
place requires a person to go out to the field unit and get an SD
card that contains the data collected by the data aquisition system.
This point-to-point communication system would make the data more accessible, especially with multiple field units. A data acquisition network could potentially have as many as 20 individual field units. Having to go to each individual unit to get their data one or two times a month takes manpower and it puts a large delay on the time between when the data is recorded and when the data is viewed. Having the entire network of data get sent to a central receiving unit gives the client the ability to see the data much faster, potentially in real time, and it eliminates the need to have someone retrieve the SD cards from the units.
Requirements and Specifications
Mechanical:
The field unit needs to be small and lightweight. There are multiple versions of the field unit. The point-to-point radio communication model is only one of these versions. Therefore, the radio components should fit in the unit with minimal redesign. It would be of great benefit if a field unit could be changed from a radio model to a non-radio model. The antenna, both transmitting and receiving, should also be cheap and easy to set up.
The field unit will be small enough to fit into a 1.5” X 5” container or will be rebuilt
Ports must be designed
The radio must connect to the field unit with a 9-pin serial port; the baud rate is expected to be 115200 Symbols/sec.
Electrical:
There are many different electrical requirements for the field units. The field units run a 12 V lead acid battery; these are connected to a solar panel. There is very limited power in the field units, so this will be an issue. Transmission will be over an unlicensed band with spread spectrum radios [3]. The data needs to be transmitted with enough accuracy to transmit over a reasonable distance.
The wireless communication addition to the system will be able to transmit up to two miles.
The components will be compatible with the AVR32 A3/A4 microprocessor.
Maximum power usage of 1.00 W
On the field unit, the radio should be able to turn off when not in use.
The bandwidth must be in an unlicensed spectrum to avoid licensing issues and keep cost down. (BW: approx. 900-920 MHz)
The antenna must not only be able to perform the bandwidth specifications, but also must be relatively cheap and easy to replace.
Radio should be able to support event detect mode and continuous mode.
An event detect system only records data when there is a seismic event.
Continuous mode is always transmitting data from the sensors.
Environment:
The field units will be installed outdoors, so the units must be very durable. The field units will have a high temperature tolerance. The units need to be able to withstand weather due to being outdoors for weeks at a time. They should be shock and vibration resistant to properly perform seismic monitoring.
The system must also follow industrial temperature specifications ,which is -40 to 85 degrees celsius [6].
Documentation:
The documentation that is written about this system will be for the hardware and the software. The hardware documentation will list all the components as well as where to buy them. Assembly of the components would also be important to document. The software documentation should have the instructions on how to interface with the radio via software. Sample code should also be provided to do so. Embedded C would be used for the field unit that transmits. MATLAB would be used to interface with the receiver.
The Documentation which relates to the microprocessor we are using is the family guide for the AVR32 A3/A4 family guide.
All of the embedded code will be written in C.
The system must transmit in packets, not a continuous data stream.
The system must be programmed in embedded C for the AVR 32 processor.
Testing will be done with MATLAB for proof of concept and then written in Embedded C for actual implementation. MATLAB will also be used to model the receiver
Testing:
Testing has the potential to have many different phases depending on how far the group gets. The first phase will involve transmission across a room; this would mostly be a proof of concept test. To really test the limits of the equipment, a series of tests to test the limitations of transmission would have to be performed. Different distances between the transmitter and receiver would have to be demonstrated. Ideally, we would be able to test the maximum distance the unit can transmit. These tests would all use MATLAB to send data to the serial port. A different set of tests would have to use embedded C.
To test the system as well as modify codes, a user can use either MATLAB or AVR32 studio.
MATLAB will be used as a test bench in order to determine the effectiveness of the radios in a controlled setting.
AVR32 studio is used to edit the embedded C code and then to download into the microprocessor on the field units.
General:
There are many more general requirements that are based on the clients preferences as well as who will be using these systems. The field units need to work with minimal adjustment and human contact. Non-technical personnel should also be able to set up the equipment in the field. There are companies in other countries interested in this product, so the radio should be legal in multiple countries.
The unit needs to be able to transmit data with minimal human involvement and adjustment.
It should be easy for non-technical personnel to set this up in the field.
There should be a central receiving unit capable of storing and processing an entire network of field transmitters.
Our client works with companies located in other countries.
The current ones are in the Philippines and Chile
This system should be legal to deploy in as many countries as possible.