Ultrasonic sensor

Introduction

Interfacing an ultrasonic sensor to measure the distance to objects in(cm) and displaying the distance on 2x16 LCD using ATmega32 with the AVR toolchain.

Hardware

AVR ATmega32 microcontroller.
Uspasp programmer
Ultrasonic sensor (HC-SR04)
2x16 LCD

Distance Calculation

Sound velocity = 343.00 m/s = 34300 cm/s

Distance of Object (in cm) = (Sound velocity * TIMER Value) / 2

                    = (34300 * TIMER Value) / 2

                    = 17150  * Timer Value

we have selected internal 8 MHz oscillator frequency for ATmega32, with No-presale for timer frequency. Then time to execute 1 instruction is 0.125 us So, timer gets incremented after 0.125 us time elapse.

             = 17150 x (TIMER value) x 0.125 x 10^-6 cm

             = 0.125 x (TIMER value)/58.30 cm

             = (TIMER value) / 466.47 cm

Circuit

Installation

You will need to have the AVR toolchain installed on your system. This includes:

avr-gcc
avr-libc
avrdude

Support

Please feel free to contact me if you have any questions/concerns. My email address is hossamelbahrawy52@gmail.com