Car Speed and Distance Safety System: April 2014

Wednesday, April 30, 2014

Week 12

On week 12, I continued my research about details of components.

Microcontroller

PIC 16F877A

The microcontroller forms the heart of the system. Its responsibilities include reading the message from the GSM modem and displaying it on LCD. Reading of message from the SIM card inserted into the modem is done by sending the appropriate AT command to the modem. Here we use MICROCONTROLLER 16F877A.

A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable I/O peripherals. Due to simplicity in design and pocket friendly prices, microcontroller is widely adopted for various fields including automobiles, medical science, defense, domestic applications, industrial use, energy management and lots more domains. Microcontrollers are commonly built using CMOS (Complementary Metal Oxide semiconductor) technology resulting optimum performance with the least consumption of power. As it is designed to perform a specific task, latency of the task is fast and is more reliable.

Pin and Description

High-Performance RISC CPU

Lead-free; RoHS-compliant
Operating speed: 20 MHz, 200 ns instruction cycle
Operating voltage: 4.0-5.5V
Industrial temperature range (-40° to +85°C)
15 Interrupt Sources
35 single-word instructions
All single-cycle instructions except for program branches (two-cycle)

Special Microcontroller Features

Flash Memory: 14.3 Kbytes (8192 words)
Data SRAM: 368 bytes
Data EEPROM: 256 bytes
Self-reprogrammable under software control
In-Circuit Serial Programming via two pins (5V)
Watchdog Timer with on-chip RC oscillator
Programmable code protection
Power-saving Sleep mode
Selectable oscillator options
In-Circuit Debug via two pins

Friday, April 25, 2014

Week 11

On week 11, I continue research to find more detailed information about the components and hardware that will be used for this project.

Ultrasonic

HC-SR04

Ultrasonic ranging module HC - SR04 provides 2cm - 400cm non-contact measurement function, the ranging accuracy can reach to 3mm. The modules includes ultrasonic transmitters, receiver and control circuit. The basic principle of work:

Using IO trigger for at least 10us high level signal.
The Module automatically sends eight 40 kHz and detect whether there is a pulse signal back.
IF the signal back, through high level , time of high output IO duration is the time from sending ultrasonic to returning.

Test distance = (high level time×velocity of sound (340M/S) / 2,

Specification:

Working Voltage: DC 5V
Working Current: 15mA
Working Frequency: 40Hz
Max Range: 4m
Min Range: 2cm
Measuring Angle: 15 degree
Trigger Input Signal: 10µS TTL pulse
Echo Output Signal Input TTL lever signal and the range in proportion
Dimension 45 * 20 * 15mm

GPS (Global Positioning System)

SKM53 GPS Starter Kit

The SkyNav SKM53 Series with embedded GPS antenna enables high performance navigation in the most stringent applications and solid fix even in harsh GPS visibility environments.

It is based on the high performance features of the MediaTek 3329 single-chip architecture, Its –165dBm tracking sensitivity extends positioning coverage into place like urban canyons and dense foliage environment where the GPS was not possible before. The 6-pin UART connector design is the easiest and convenient solution to be embedded in a portable device and receiver like PND, GPS mouse, car holder, personal locator, speed camera detector and vehicle locator.

Applications: LBS (Location Based Service) Vehicle navigation system PND (Portable Navigation Device) GPS mouse and Bluetooth GPS receiver Timing application