Final Design Report Project Name: Team Name: The Messengers · EEL 4924 Electrical Engineering...

EEL 4924 Electrical Engineering Design

(Senior Design)

Final Design Report

23 April 2013

Project Name: Project Hermes

Team Name: The Messengers

Team Members:

Name: Jerrod Langston Name: Krystina Watkins

Project Abstract:

Our project consists of a remote control car that can be driven from the perspective of the car itself. A

camera will be mounted on the front-end of the car; video data from the camera will first pass through an

FPGA for processing before being transmitted through a set of transceivers ending at the location of the user.

The data will pass through another FPGA and processed for output to an LCD. The FPGA at the user will

also be used to process inputs from the user as control signals for the RC car. The car platform will have

rear-wheel drive and front-wheel steering (similar to many commercial RC cars). The motor drivers for the

car will be designed and built “in-house” so that we have good control over speed. The FPGA on the car will

also be used to process the control signals for steering and driving.

University of Florida EEL 4924—Spring 2013 23 Apr 13 Electrical & Computer Engineering

/10 Final Design Report: Project Hermes

Table of Contents:

Project Abstract………………………………………………………………….……..…1

Introduction and Features……………………………………………………….……...…3

Technical Objectives…………………………………………………………….………..3

Technology Selection…………………………………………………………….……….3

Division of Labor…………………………………………………………...…….……....4

Gantt Chart……………………………………………………………………….……….5

PCB Design……………………………………………………………………………….5

Final Product……………………………………………………………………………...7

Cost and Build of Materials……………………………………………………………….10

List of Figures:

Figure 1: System Block Diagram……………….…………………………………………3

Figure 2: Camera Breakout PCB…………………………….……………………………5

Figure 3: PSP TFT Breakout PCB……………………….…….………………………….5

Figure 4: Car Side PCB…………………………………………….……………………..6

Figure 5: Controller Side PCB……………………………………………………………6

Figure 6: Final Motor Driver PCB……………………………………………………..…6

Figure 7: Final Car Side PCB Design…………………………………………………..…7

Figure 8: Final Controller PCB Design………………………………………………...…7

Figure 9: Final Charger Circuit……………………………………………………………8

Figure 10: Motor Driver Circuit - Rev 1.0………………………………………………..8

Figure 11: Motor Driver Circuit - Rev 2.0………………………………………………..9

Figure 12: Final Motor Driver Circuit………………………………………………….…9

List of Tables:

Table 1: Gantt Chart………………………………………………………………………5

Table 2: Cost and Build of Materials……………………………………………………..10



Introduction and Project Features:

The goal of this project is to design and implement an RC car that can be driven from a first-person view.

This project is divided into two separate modules: the module on the car and the module at the driver. The

module on the car has a camera, transceiver, and motor driver to record and transmit video and remotely

control the car. The module at the driver has a transceiver and LCD to display the video feed. Also contained

on the modulate at the driver is a controller (e.g. joystick or steering wheel).

Technical Objectives: The primary objective is to design a system that can transmit and receive video wirelessly at a reasonable

frame rate. The secondary objective is to design and implement the RC car platform that enables control

from the user.

The first problem that must be solved is interfacing the CMOS camera element with the FPGA. The

camera operation is controlled using an I2C protocol that will be run from the FPGA. Image

information is output by the camera element using a VGA protocol and received by the FPGA. The

image data will then be manipulated for transmission.

The FPGA communicates with the transceiver modules using an SPI protocol, and is used to control

the operation of the transceiver and writing/reading data transmitted/received by the transceivers.

After the image data is received by the system at the user, the FPGA will manipulate the data for

output to an LCD (this will be done using a serial protocol).

Control signals will be taken from some physical input device and processed by the FPGA (e.g.

joystick, steering wheel, pedal, D-pad) (n.b. in the case that a device with analog output is used, an

ADC will have to be used to communicate with the FPGA)

The control signals will be transmitted from the system at the user to the system on the car to be

processed by the FPGA on the car.

Depending on the control signal values, the FPGA will output a PWM signal to control the servo on

the car used for steering and outputs a signal to control the motor driver (H-bridge) which controls

the rotational speed and direction of the DC motor used for driving the car.

Technology Selection:

Figure 1: System Block Diagram



Listed below are the primary electrical components used in our project, and the reasons for choosing these

components.

Altera FPGA:

An FPGA was chosen as the primary, digital “workhorse” for both modules in order to more easily

have high throughput for the streaming of image data. By utilizing an FPGA, the bottleneck is not

placed on the primary processing unit, but on the peripherals chosen: in this case the bottle neck will

occur at the wireless transceiver that can transmit (at best) 2 Mbps, which must include the overhead

of the transmitted packets (e.g. address and error correction).

The Altera brand was chosen because we have the most experience with Altera FPGAs and already

have Cyclone II and III development boards for prototyping

Nordic 2.4 GHz Transceiver:

We did not want to use Wi-Fi to transmit video, therefore we were primarily limited to 2.4 GHz

transceiver modules, such as XBee or Nordic. Though XBee’s are readily available and widely used,

we chose the Nordic transceiver because it has much higher data rates (2 Mbps vs. 250 kbps).

The transceiver also utilizes SPI for communication between devices which is simple to use

640 x 480 CMOS Camera:

The CMOS camera was chosen for its small size, low resolution, RGB color capabilities, and ability

to provide 30 fps

This camera communicates using an I2C interface

PSP TFT:

The PSP TFT was chosen because it is a reasonably large display and can easily be viewed by

the driver

The LCD is controlled using HSync, VSync, and 24 color data pins

H-Bridge:

An H-bridge must be designed in order to control the DC motors used for driving the RC car.

A PWM signal will be provided by the FPGA to the H-bridge

Division of Labor:

Jerrod Langston:

Transceiver VHDL

PSP TFT Circuit and VHDL

Camera VHDL

SDRAM VHDL

Charging Circuit and PCB Design

Krystina Watkins:

Camera Circuit and PCB Design

PSP TFT PCB Design

Final Car Side PCB Design

Final Controller PCB Design

Motor Driver Circuit and PCB Design



Gantt Chart:

Table 1: Gantt chart

PCB Design:

Figure 2: Camera Breakout PCB Figure 3: PSP TFT Breakout PCB



Figure 4: Car Side PCB

Figure 5: Controller Side PCB

Figure 6: Final Motor Driver PCB



Final Product:

Figure 7: Final Car Side PCB Design

Figure 8: Final Controller PCB Design



Figure 9: Final Charger Circuit

Figure 10: Motor Driver Circuit – Rev 1.0



Figure 11: Motor Driver Circuit – Rev 2.0

Figure 12: Final Motor Driver Circuit



Cost and Build of Materials:

ITEM QTY UNIT COST TOTAL COST

GENERAL

Advanced Circuits PCB 2 66.00 132.00

IC CYCLONE III FPGA 16K 240PQF 2 29.10 58.20

IC CONFIG DEVICE 4MBIT 8-SOIC 2 13.00 26.00

DRAM 64M (4Mx16) 166MHz SDRAM, 3.3V 2 3.03 6.06

Transceiver nRF24L01+ Module with RP-SMA 4 19.95 79.80

2.4GHz Duck Antenna RP-SMA 4 7.95 31.80

HCMOS 5 x 3.2mm 2.5V Oscillator 2 1.68 3.36

IC REG LDO 5V .95A SOT-223 1 0.54 0.54

IC REG LDO 3.3V .95A SOT-223 2 0.54 1.08

IC REG LDO 2.5V .95A SOT-223 2 0.62 1.24

IC REG LDO 1.2V .95A SOT-223 3 0.48 1.44

Power Switch 2 1.74 3.48

Tactile Reset Button 3 0.10 0.30

CAR TRANSMIT

Dominus Short Course Electrical Truck 1 199.99 199.99

TCM8230CMD Camera 1 9.95 9.95

LCD RECEIVE

Color 24-Bit LCD 4.3" PSP 480x272 1 39.95 39.95

Joystick 2 9.95 29.90

MCP3004 (ADC) 1 2.50 2.50

LT1932 (LED Driver) 1 4.19 4.19

MAX6820 (Power Supply Sequencer) 1 3.73 3.73

MOSFET N-CH 200V 18A D2PAK 1 1.84 1.84

TRANS GP NPN 200MA 40V SOT223 1 0.51 0.51

CONN FPC/FFC 40POS .5MM R/A SMD 1 1.95 1.95

CONN FPC/FFC 4POS .5MM R/A SMD 1 0.86 0.86

4.7 µH Inductor 1 0.35 0.35

MOTOR DRIVER

H11AA1 (Opto-Isolator) 4 1.14 4.56

IRF640 (NMOS) 2 1.59 3.18

IRF9540 (PMOS) 2 1.72 3.44

BDX53C (NPN Darlington) 4 0.625 2.50

CHARGER CIRCUIT

IC SENSOR PREC CENT TEMP TO92-3 1 1.57 1.57

LT1635 OP AMP 2 3.89 7.78

TIP32A TRANS GP PNP 3A 60V TO-220 1 0.59 0.59

LM317 (Adjustable Voltage Regulator) 1 0.80 0.80

L7805 (5V Regulator) 1 0.48 0.48

POWER

Venom Power 8.4V 5000mAH Battery 1 43.99 43.99

TENergy NiMH 6V 2000mAH Battery 1 10.00 10.00

TENergy NiMH 7.2V 2000mAH Battery 1 10.00 10.00

TOTAL 729.91

Table 2: Cost and Build of Materials

Final Design Report Project Name: Team Name: The Messengers · EEL 4924 Electrical Engineering...

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