PSU “Moonbuggy” Telemetry Data Logging Base System
Designed by Richard Erickson
In the past, some of the previous PSU entries into “The great American Moonbuggy
Race” have been “over built” in areas that would cause an unnecessary weight addition to the
human powered “moonbuggy” thus requiring more “human power” to propel the “moonbuggy”
around the race course. While component analysis and simulation is already being performed to
determine engineering design possibilities and limitations, as is normal during the design process,
it is still a guess without any information about the “real” forces and strains placed on
components during the race. The PSU “Moonbuggy” Telemetry Data Logging Base System is
designed to measure, gather, store, and transmit “real time” data for the purpose of engineering
analysis.
The process of acquiring this “real” information in this application presents a number of
limitations in the design of a data gathering and logging system. The data gathering components
and system must be as unobtrusive as possible and not interfere in any way with the operation of
the buggy or its riders. The data logging portion of the system must be onboard and\or wireless to
a remote location as the buggy cannot be connected to anything external by hardwires during the
competition.
The sensor and signal conditioning circuitry in this design will comprise five telemetry
sub-systems. Strain gauges will be placed at various locations as recommended by the buggy
design team with tri-axis accelerometers placed as close as possible to the four wheels and one on
the frame. The strain gauge sensors will be “hard wired” with short leads to the sensor signal
conditioning circuitry which will be mounted with or close to the accelerometers. The signal
conditioning circuitry will be “overbuilt” with extra sensor input capacity to easily facilitate the
connection of additional sensors.
In addition to the five subsystems there will be a GPS device to provide precise GPS
location data of the “sensor events” when they happen.
The data signal output leads and operating power input leads from these five sub-systems
and GPS will be wired to the telemetry system’s main data control unit. The telemetry system’s
main data control unit will consist of a PIC microcontroller and an “on-board” telemetry data
storage setup using a SD memory card connected to a communication bus on the microcontroller.
A software program is to be written for the microcontroller system operation and will include the
required sampling rates for the different types of sensors used at this time, the processing of
sensor data for the on-board data storage medium, and the processing and control of the data to be
sent by the RF data transmission component to a remote monitoring location.
The RF transmission component shall have a minimum transmission range of one-half
(1/2) mile and have the necessary bandwidth and data through-put to accommodate future
telemetry system expansion(s) as well as video data transmission so that future additional
transmitters (more system weight) will not have to be added to expand the overall system. The
transmitter must be of a design that will not add any unnecessary weight or power drain to the
overall system.
A color video camera will also be onboard, if possible. The design and development of
the telemetry system’s main data control unit required including the provisions for adding the
requested telemetry system functions of wireless gathering of human bio data and wireless helmet
cams. The development of these additionally requested system functions has proceeded
concurrently with the main data control unit development through an independent study course.
Block Diagram of “Base” Telemetry System
XY Z
Inputs
Sensor Group 1 of 5
Tri-A x is A cc eleromet er
St rai n
Gauge
St rai n
Gauge
St rai n
Gauge
St rai n
Gauge
St rai n
Gauge
MCP6S28
8 Channel
Input
PGA
DC Power and
Ground Feed
DC Power and
Ground Feed
Sensor Data
And
PGA Control
Erickson
11/01/2006
Rev 1
Moonbuggy
Telemetry Arthur
System
Richard
1
Battery Pack
DC Power and
Ground Feed
DC Power and
Ground Feed
Microhard
IP921
RF Modem
Transceiver
PIC18F4550
Microcontroller
SD Card
On-Board
Data Memory
Processed
Telemetry
Data