Xbee Wireless Throttle Position Sensor and Control

Presenters: Miquel Moe and Eleanya Onuma

Mentor: Professor Anderson

Department of Electrical Engineering

Agenda

• Introduction• Equipment• Procedure• Results• Conclusion• Acknowledgements

Introduction

• Our goals in this design:-Build a throttle position sensor prototype-Control the throttle of the throttle

position sensor wirelessly-Implement a temperature sensor that

will monitor the temperature of the throttle for safety

Introduction

• What is a throttle?-Regulates the flow of fluid and/or air -This regulation is maintained by position of the flap

• What is a throttle position sensor?-Monitors the position of the throttle -Has an associated output (resistance,

voltage…) with every position

Throttle Position Sensor• ADC 0804 IC chip• 0.1uf, 10uf and 147pf

Capacitors• 10k Ω Potentiometer• E3630A Agilent Triple Output

Power Supply• 741 op amp• Switch • 7 Segment Display• Wires• EPROM• SN74LS47

Procedure• Design specification for the Throttle Position

Sensor

Angle in Degrees Output Voltage (V)

0 0.5

22.5 1.5

45 2.5

67.5 3.5

90 4.5

Vout

Graph

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10.5

1

1.5

2

2.5

3

3.5

4

4.5

Rp/R

Vout

(Volt

s)

Throttle Output

Microprocessor-Compatible 8-bit A/D Converter (ADC0804LCN)

Vout from Diff op amp

Test DAC input and output :

Angle (Degree)

Voltage from Op amp (V)

Vout from ADC in base 10

Vout from ADC in binary

0 0.5 25 0001100122.5 1.5 76 0100110145 2.5 128 10000000

67.5 3.5 179 1011001190 4.5 230 11100110

ADC EPROM 7- Segment DisplaySN74LS47

• 10k potentiometer• Cylindrical container(oatmeal box)• Pen • Epoxy• Electric tape• Wires• 5volts Unipolar Stepper motor• Darlington transistor.

Throttle Design and control

Pictures of the Throttle

Stepper motor• A stepper motor as the name suggests is an electric

motor that can divide a full rotation into a number of steps.

• Unlike the conventional DC motor that rotates whenever voltage is applied across the terminal, a stepper motor is controlled using a stepper motor controller or a microcontroller following a unique sequence.

• Unipolar stepper motor specification.35L048B1U-N

STEP 01 02 03 04

1 ON OFF ON OFF

2 ON OFF OFF ON

3 OFF ON OFF ON

4 OFF ON ON OFF

Clockwise Rotation

Counter-clockwise Rotation

Arduino• Arduino is an open-source electronic prototyping

platform.

The Atmega microcontroller on the board is programmed using Arduino Programming language which is based on C/C++

We programmed the MCU to control our stepper motor using serial input sent through a Xbee radio

Xbee(Zigbee)• Xbee is a low power, wireless mesh networking

standard. • Mesh networking is a method of routing data

between nodes in a network.

Configuring the Xbee radios

- -Arduino A Xbee A

SenderDATA Xbee C

Receiver Arduino C

X-CTU software• Set baud rate for Xbee radios•Upgrade firmware•Test Range

Program the Arduino

Arduino A Arduino C

•Wire Circuit

Temperature SensorEquipments• 10k Thermistor• 10kΩ Resistor• LCD( Liquid Crystal Display)• 10uf capacitor• Speaker• Wires

• Thermal resistor also known as a thermistor is a resistor whose resistance vary with temperature.

• Steinhart-Hart equation is used to model the resistance on the thermistor at different temperatures.

Where A, B C are Stienhart-Hart coefficient and vary by from type and model of thermistor

T = Temperature in KelvinR = Resistance in ohms at different Temperature

Wire Up the Circuit

Program the Arduino•Program the Arduino using the Steinhart-Hart Equation and Coefficients

Arduino C

System shut down• Comparator – compares two voltages• Buffer amplifier

RESULTS• Temperature readings

•Throttle and throttle Position Sensor(degree error due to design)

7.5˚ 5.5˚