TelosB Charging and Energy Meter Kit(Dec1201)

www.seniord.ece.iastate.edu/dec1201

TelosB Charging and Energy Meter Kit(Dec1201)

Group Leader: Tomas MullinsCommunicator: Casey LieblWebmaster: Shiya LiuTeam Members: Andrew Gurik & Qiao Huang Advisor: Dr. Daji Qiao


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Problem StatementTelosB Charging/Metering Kit

Power from 3 sources Charge AA or AAA Batteries NiMH or Alkaline Monitor Current, Voltage, & Power

Deliverables 3 Fully Functional Kits Complete Design and Testing Documentation


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TelosB

Wireless Sensor Module Low Power For

Experimentation/Research Open Source Operating

System - TinyOS


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Powercast Receiver

Remote Wireless Power For Low Power

Applications 40-45 Foot Range Maximum 4.2V 100mA

http://www.powercastco.com/products/powerharvester-receivers/





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Sundance Solar

Small Solar Panel For Low Power

Applications 4V produced by solar

panels 3.5V output after

protection diode


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Batteries

NiMH (Nickel-Metal Hydride) 1.2 Volts per Cell Charges at 1.4 Volts

Alkaline 1.5 Volts per Cell Charges at 1.65 Volts


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Big Picture


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Users & Uses

iCube Sensors Lab EE 423: Communication Systems Laboratory CprE 546: Wireless and Sensor Networks CprE 454/ComS 554: Distributed and Network

Operating SystemsFor Research of Energy Replenishment for

Wireless Sensor Networks


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Requirements

The entire system must keep power consumption to a minimum

The device must be able to receive inputs from USB, a Sundance Solar charger, or a Powercast Receiver

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 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

Functional Non-functional


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Additional InformationConstraints:

Production costs ($500 max for three devices at $100 per unit)

Time: Device must be working by December 2012

Potential Risks: Power Consumption Over-charging Batteries Over-voltage on TelosB Battery life of removable batteries

Market Research: The market has many options for wireless sensors with a

charging kit. Many of these devices do not have metering kits for voltage, current and power.


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Design Decomposition

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


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Functional Block Diagram


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Circuit Diagram


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Microcontroller Justifications

MSP430

Pros•Low Power Consumption

•USB Interface•Small Size•Inexpensive

Cons•Expensive Test Board

•QFN Package

PICPros•Low Power Consumption

•USB Interface•DIP Package

Cons•Larger Size•Slightly More Expensive

Arduino

Pros•User Friendly•Powerful System•USB Interface

Cons•Higher Power Consumption

•Expensive•Complex System•Large Size


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Diode Justifications

Traditional

Pros• Inexpensive•Low Leakage Current

Cons•High Voltage Drop

Germanium

Pros•Low Voltage Drop

Cons•Expensive•Difficult to Find•Temperature Sensitive

•High Leakage Current

Schottky

Pros•Low Voltage Drop

Cons•Expensive•Higher Leakage Current


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Regulator Justifications

Diode

Pros• Inexpensive• Simple

Cons• High Power

Consumption

LM317

Pros• Easy to Implement• Provides

overvoltage protection

• Good Voltage Control

Cons• Expensive


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Regulator Testing

22.1

25 2.252.3

75 2.52.6

25 2.752.8

75 33.1

25 3.253.3

75 3.53.6

25 3.753.8

75 4

4.124

99999

99999

94.2

54.3

75 4.5

4.624

99999

99999

94.7

54.8

75 50

0.5

1

1.5

2

2.5

3

3.5LM317 Vout vs. Vin

Vin(Volts)

Vout

(Vol

ts)


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Cost

DESCRIPTION QTY UNIT PRICE

TOTAL PRICE

Schottky Diode 10 3.36 33.60USB connector 3 1.48 4.44Battery chassis 3 0.94 2.82PIC microcontroller 3 2.8 8.4

TOTAL COST 49.26*All other parts available from the Electronics Shop


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Hours Consumed for Spring Semester

Name Total HoursTomas Mullins 28Casey Liebl 27Qiao Huang 27Andrew Gurik 30Shiya Liu 28

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Implementation PlanProgram

Microcontroller

Build Circuit on Breadboard

Test Circuit

Build Circuits on Printed Circuit

Boards

Final Testingwww.seniord.ece.iastate.edu/dec1201


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Schedule


Questions?


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Scenario A: Power Source Connected, Charging Batteries,

Reporting to TelosB


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Scenario B: Power Source Connected, Charging Batteries,

Reporting to PC


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Scenario C: Power Source Connected, Not Charging Batteries,

Reporting to TelosB


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Scenario D: Power Source Connected, Not Charging Batteries,

Reporting to PC


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Scenario E: No Power Source Connected, Reporting to TelosB


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Microcontroller Power Comparison

Implementation Currents

DeviceCurrent (mA)

TelosB Duty Cycle: 1% 1% 1% 10% 10% 10% 50% 50% 50% 100% 100% 100%uController Duty Cycle: 10% 50% 100% 10% 50% 100% 10% 50% 100% 10% 50% 100%

PIC

0.335 0.778 1.333 2.296 2.740 3.295 11.014 11.458 12.013 21.912 22.355 22.910MSP430 0.275 0.481 0.738 2.237 2.442 2.700 10.955 11.160 11.418 21.852 22.058 22.315

Difference: 0.060 0.298 0.595 0.060 0.298 0.595 0.060 0.298 0.595 0.060 0.298 0.595

2600 mAhLifetime - AA NiMH

DeviceLifetime (days)

TelosB Duty Cycle: 1% 1% 1% 10% 10% 10% 50% 50% 50% 100% 100% 100%uController Duty Cycle: 10% 50% 100% 10% 50% 100% 10% 50% 100% 10% 50% 100%

PIC 324 139 81 47 40 33 10 9 9 5 5 5MSP430 394 225 147 48 44 40 10 10 9 5 5 5

Difference: -70.249 -86.135 -65.516 -1.260 -4.818 -7.247 -0.054 -0.252 -0.470 -0.014 -0.065 -0.126

Current consumption:

Battery Life:

http://www.ti.com/mcu/docs/mcuorphan.tsp?contentId=61835&DCMP=MSP430&HQS=Other%2bOT%2bulp

http://www.ti.com/mcu/docs/mcuorphan.tsp?contentId=61835&DCMP=MSP430&HQS=Other+OT+ulp

http://www.ti.com/mcu/docs/mcuorphan.tsp?contentId=61835&DCMP=MSP430&HQS=Other+OT+ulp

TelosB Charging and Energy Meter Kit(Dec1201)

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