1. SONAR SOund NAvigation Ranging By Dale Williams Tech Topic 12/1/04

2. HOW SONAR WORKS Sonar works by sending out a pulse of high frequency sound and measuring the time it takes to be reflected back to it’s origin. If the speed of sound in the medium is known, the distance from the object can be determined.

3. THE BASICS ELEMENTS OF SONAR Frequency Generator Frequency Generator Electro acoustic Transducer Electro acoustic Transducer Tone Decoder Tone Decoder Precise Timer Precise Timer Output Decoder Output Decoder

4. TRANSMITTER The transmitter consists of a frequency generator and a transducer. The Frequency determines the beam angel that the sonar views. The lower the frequency the larger the view area. The transducer is usually a Piezo electric element and is what produces the sound. Transducers are made for specific frequencies and must be match to the transmitter frequency. The transmitter consists of a frequency generator and a transducer. The Frequency determines the beam angel that the sonar views. The lower the frequency the larger the view area. The transducer is usually a Piezo electric element and is what produces the sound. Transducers are made for specific frequencies and must be match to the transmitter frequency.

5. Receiver After the transmitter has finished transmitting a burst of sound a timer is started and the tone decoder is activated. When the sound is received by the transducer the timer is stopped and the distance is calculated using a processor. After the transmitter has finished transmitting a burst of sound a timer is started and the tone decoder is activated. When the sound is received by the transducer the timer is stopped and the distance is calculated using a processor. The transducer can be the same one used to transmit or a separate one depending on the device.

6. SONAR BUILDING SPECIFICS The three parts needed to build a simple SONAR system are a microcontroller (HC08-11-12 etc.), a transducer, and a tone decoder. A simple decoder that I found is a NE567N. NE567N Specs: Vcc 10v Vcc 10v Output on: 100ma sinking Output on: 100ma sinking Output off: Open collector Output off: Open collector 8 pin DIP 8 pin DIP Frequency range.01hz-500khz determined by 2 resistors and a capacitor Frequency range.01hz-500khz determined by 2 resistors and a capacitor There are verity of transducers for water and air applications of different frequencies.

7. SOFTWARE OVERVIEW 1 Output xxKhz pulse to transducer 1 Output xxKhz pulse to transducer 2 Start timer and activate NE567 2 Start timer and activate NE567 3 Stop timer when NE567 output = false 3 Stop timer when NE567 output = false 4 Store timer Value 4 Store timer Value 5 Calculate distance/2= 5 Calculate distance/2= 6 Output value to a/d converter or digital output 6 Output value to a/d converter or digital output

8. FEASABULITY This sonar system is cost effective and could be built for under $20. The sonar system\ range finder would take minimal circuitry but a substantial amount of software development. For our application to determine the depth of our device a pressure sensor with a output proportional to depth may be a simpler, better option. This sonar system is cost effective and could be built for under $20. The sonar system\ range finder would take minimal circuitry but a substantial amount of software development. For our application to determine the depth of our device a pressure sensor with a output proportional to depth may be a simpler, better option.

9. Questions?