Developed Tor: The University of Rhode Island GSO
(This project developed jointly with TechEn, Inc.)
Key Technologies:
Microprocessor: TI MSP430F149
RF Device: Satellite Transmitter Module
Battery: Custom Lithium Battery Pack
The Problem:
Design the hardware and firmware infrastructure for an instrumentation probe that will
operate underwater for over one year maximizing the value of a limited battery supply.
The Solution:
When operating from batteries, current consumption is always an issue.
Because this probe is dropped into the ocean and spends a year or more acquiring data,
tracking current consumption becomes an obsession.
Over one year, a casual 100 microamps of "standby" current turns into 877 milliamp hours.
This exceeds the power capacity of an 'AA' NiCad.
So, even small leakage currents matter.
The entire unit needed to be designed to minimize power consumption.
Working with the client, CoAutomation assisted in creating a distributed power system
for the probe, which allowed the various electronic peripherals to be sequentially powered-up
when needed and completely powered off when not in use.
The data acquisition subsystems were carefully designed to minimize wasted power during operation.
This required not only careful attention to power consumption of the circuits, but also proficiency in
designing firmware that shortened microprocessor execution time.
Similarly, the Flash Data storage is powered only when actually recording or retrieving data records.
The entire instrumentation package is controlled by an MSP430F149 low-power microcontroller.
CoAutomation developed a firmware task control structure that allows the MSP430 to operate in
low-power modes most of the time even when processing incoming real-time data.
The proper combination of hardware resources and firmware drivers allows low-overhead
operations and reduces the need for unnecessary interrupt responses.
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