Upload
mavis-pope
View
214
Download
0
Tags:
Embed Size (px)
Citation preview
1
Problem Statement
TelosB Charging/Metering Kit• Power from 2 sources• Charge AA or AAA NiMH batteries• Monitor Current, Voltage and Power
Deliverables• 3 Fully Functional Kits• Complete Design and Testing Documentation
www.seniord.ece.iastate.edu/dec1201
2
TelosB• Wireless Sensor Module• Low Power• For Experimentation/
Research• Open Source Operating
System-TinyOS
www.seniord.ece.iastate.edu/dec1201
3
Sundance Solar Panel• Small Solar Panel• For Low Power Applications• 4V produced by solar
panels
www.seniord.ece.iastate.edu/dec1201
5
Users & Uses• iCube Sensors Lab
▫ EE 423: Communication Systems Laboratory▫ CprE 546: Wireless and Sensor Networks▫ CprE 454/ComS 554: Distributed and Network
Operating Systems
• For Research of Energy Replenishment for Wireless Sensor Networks
www.seniord.ece.iastate.edu/dec1201
6
RequirementsFunctional Non-Functional
• The entire system must keep power consumption to a minimum
• The device must be able to receive inputs from USB or a Sundance Solar charger
• Must sample power usage every 0.1 seconds
• A computer must display the real time data points and store the data
• At least an 8 bit ADC resolution on voltage measurements 0-3 Volts
• Output the readings to the TelosB device or a PC via USB
• The size of the device must be limited to 2 AA plus 2 AAA batteries and about 1 inch tall
• The system should be neatly integrated
• The device could have a sturdy packaging solution
www.seniord.ece.iastate.edu/dec1201
7
Design Decomposition
www.seniord.ece.iastate.edu/dec1201
TelosB Charging & Metering Kit
Charging
Smart Charger
Batteries
Provides Power
Metering
Measures Voltage via
ADC
Calculates Current
Calculates Power
Microcontroller
ADC
Controls Circuit
Reports via USB
Regulator
Maintain Voltage
Protection
Overcharging
Overvoltage
Back Current
10
Microcontroller Justification
www.seniord.ece.iastate.edu/dec1201
MSP430
PIC Arduino
Pros•Low Power Consumption
•USB Interface•Small Size•Inexpensive
Cons•Expensive Test Board
•QFN Package
Pros•Low Power Consumption
•USB Interface•DIP Package
Cons•Larger Size•Slightly More Expensive
Pros•User Friendly•Powerful System•USB Interface
Cons•Higher Power Consumption
•Expensive•Complex System•Large Size
11
Regulator Justification
www.seniord.ece.iastate.edu/dec1201
Diode LM317Pros• Inexpensive• Simple
Cons• High Power
Consumption
Pros• Easy to Implement• Provides
overvoltage protection
• Good Voltage Control
Cons• Expensive
Buck/Boost
Pros• Boosts Voltage to
use for ADC• Good Voltage
Control
Cons• Difficult packaging• Not adjustable
(fixed voltage)
12
Multiplexer Justification
www.seniord.ece.iastate.edu/dec1201
2:1 MUXPros
• Inexpensive• Low resistance
switch• Easily controlled• Small leakage
current
Cons• Packaging
Pros• Packaging
Cons• Larger voltage
drop
Transistor