02/13/2002 Team Epimetheus 1

Team EpimetheusWireless Robot Module

Matt Beerman

John Fatica

Hubert Ho

Erik Justen

Brad Kramer

Matt Rankin

Karl Yeh

EE682Dr. Steven Bibyk

02/13/2002 Team Epimetheus 2

Objective

• To build a wireless sensor module using the robot platform.

• To gain knowledge and experience for future projects and presentations.

• To have a technical understanding of projects and designs.

02/13/2002 Team Epimetheus 3

Platform Specification

• Wireless sensor module is to collect data from the OSU-FIRST robot

02/13/2002 Team Epimetheus 4

Block diagram

Sensor Array

Host MCU

Power Management

Wireless Communication

Interface

X10 Video System

User Interface / Receiver /

Video Capture

Analog / Digital

Conversion

= Power Lines

= Data Lines

02/13/2002 Team Epimetheus 5

Matrix ManagementHost MCU

Power Sensors Wireless User Int. Video

Matt Beerman P

John Fatica P P

Hubert Ho P

Erik Justen S P

Brad Kramer P

Matt Rankin P S

Carl Yehman PP = Primary Lead S = Secondary

02/13/2002 Team Epimetheus 6

Micro-Controller Unit

• Microchip PIC (16F877)

– Programmed in assembly using MPLAB

– 4 MHz Clock Speed

– Built-in Synchronous Serial Port (SSP) and Universal

Synchronous/Asynchronous Receiver/Transmitter

(USART)

– 8K of FLASH program memory; 368 bytes data memory

02/13/2002 Team Epimetheus 7

• PIC communication with A/D

– PIC to MAXIM A/D communication performed using Serial Peripheral Interface (SPI) compatible bus through SSP module.

– PIC acts as the master and generates the clock at a rate of Fosc/4.

– Data is simultaneously clocked in/out of SSP buffer.

– RPM and Battery Voltage data checked on-board the PIC for validity.

Micro-Controller Unit

02/13/2002 Team Epimetheus 8

• PIC Communication with PC– Standard RS232 serial link

– Take advantage of built in USART on PIC• PIC hardware handles construction/transmission of each byte

and baud rate timing issues

• Achieve transmit speeds up to 19200bps

• Too much error in baud rate calculation past 19200

– Assemble 23 byte data packet and send

Micro-Controller Unit

02/13/2002 Team Epimetheus 9

Micro-Controller UnitCode Overview

Start

InitializePIC

Read/StoreADC Data

Data TestRoutine

TransmitData

Main Routine Data Test Routine

RPMValid?

Flag RPM bitin TX Packet

Flag BATT bitin TX Packet

BATTValid?

NO

NO

YES

Generate 16-bitChecksum

02/13/2002 Team Epimetheus 10

Power Management

• Power Supply– 12 volt lead acid battery

• +/-12v, +/-10v, +6v, +/-5v

– 3 adjustable regulators• National Semiconductor

• LM2991

• LM2941

02/13/2002 Team Epimetheus 11

Power Management

• Management– Monitoring of voltage levels in the battery– Auto shutdown of the video

2941

2941

2991

12 V

12 V

+12

+10

+6

+5

GND

-5

-10

-12

10Ω/5W

10Ω/5W

= Resistor

02/13/2002 Team Epimetheus 12

Sensors

• RPM Sensor (2)– Purpose

• Will be used to count the number of rotations of a particular wheel in order to approximately determine the velocity of the robot.

– RPM Sensor Components• A pinwheel with alternating reflective and non-reflective

surfaces.

• An Omron reflective sensor (continuous beam)

• A 8-bit binary counter (TI SN74HC590A)

• A 8-bit DAC (National DAC0808)

• An Op-amp

02/13/2002 Team Epimetheus 13

Sensors

• Temperature Sensor (2)– Thermometrics NTC Thermistor

• Epoxy coated solid state sensor

• Suitable for PCB and probe mountings

• Current Sensors (3)– One 100 amp sensor for battery current

• F.W. Bell BB-100 Hall effect current sensor

– Two 25 amp sensors for motor current• Amploc Amp25 current sensor

02/13/2002 Team Epimetheus 14

Wireless Communication

• Requirements– Send data and video from sensor module to User

Interface computer

– Transmit data up to 100 meters

• Solution– Wireless Serial link

– Parallax RF product (27987, 27986)• 433.92 MHz

• 250 feet

02/13/2002 Team Epimetheus 15

Wireless Communication

• Packet Definition

SYNC BYTES (4 BYTES)

5A5AA5A5

PACKET INFO

(1 BYTE)

DATA

(16 BYTE)

CHKSUM

(2 BYTE)

02/13/2002 Team Epimetheus 16

Server Daemon

• Utilizes java packages– javax.comm

– java.net

– Cross-platform

• Threads used for opening new network sockets• Formats serial data for passing to applet

02/13/2002 Team Epimetheus 17

Program Flow

• Wireless Serial Data to Server Daemon

• Daemon network Thread passes info to Applet

• Multiple graphics threads update applet

02/13/2002 Team Epimetheus 18

User Interface

GUI

• Java Applet

• Displays Values and Graphs -

• RPM Wheel Data (2)

• Temperature Data (2)

• Motor Current Data (2)

• Battery Current Data

02/13/2002 Team Epimetheus 19

Proposed Schedule

W1 W2 W3 W4 W5 W6 W7 W8 W9

Schematic / Algorithm Dev.

Parts Acquisition

Build/Test

Host MCU

Power

Sensors

Wireless / Communications

User Interface

Video

System Integration

02/13/2002 Team Epimetheus 20

Moving Forward

•Continue parts acquisition

•Re-acquire PIC

•Once parts are in:

– Continue sensor work

– Continue UI integration

– Add in wireless comm.

– Test and debug

•Time permitting, incorporate video