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### Topic: ultrasonic transducer arduino circuit- plz plz plz help! (Read 1 time)previous topic - next topic

#### elasticity19

##### Apr 26, 2011, 01:34 pm
hi all,
I need help with my uni project and i have been stuck at this point for days.
All i want to now is to transmit ultrasound using the arduino board. AND THATS IT!! I dont want want to detect or anything else at this point .
this is the UT i am using http://www.jaycar.com.au/products_uploaded/AU5550.pdf
and this is my source code

const int pingPin = 9;

void setup() {

}

void loop()
{

pinMode(pingPin, OUTPUT);
digitalWrite(pingPin, LOW);
delayMicroseconds(2);
digitalWrite(pingPin, HIGH);
delayMicroseconds(23);

}

negetive pin is grounded and positive pin is connected to 5v.
My question are :-
From my calculation ,  the frequency is 40kHz . Am i right ?
2)how can i calculate the p-p voltage ?
3) Do i need to use a op-amp to drive the ut ?
4)Also is there any to know if the UT is working ?

I am a real noob with electronics and so plz help me with this.

#### johnwasser

#1
##### Apr 26, 2011, 02:59 pm
Code: [Select]
`const int pingPin = 9;void setup()     { tone(9, 40000); }void loop() { }`

If you use a digital output the Peak to Peak voltage is 5 volts (or very close to it).

I don't know how you would detect the 40 kHz signal without a oscilloscope.  If you had a second Arduino and a second transducer you could try playing a 41000 Hz tone and listen for the 1 kHz beat frequency.
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#### elasticity19

#2
##### Apr 27, 2011, 01:17 pm
hey mate,
Thanks for the code . Will give it a go now.
now just to make sure, so i can just connect my UT to the arduino pins and thats it?
do i need any amplifier or anything else at all ?

thanks

#### johnwasser

#3
##### Apr 27, 2011, 02:35 pm
The transducer will take up to 140 volts (when sending 0.4 milliseconds pulses every 10 milliseconds) so I don't think you will get much volume at 5 volts.  You may want to add a transformer and driver transistor to boost the voltage.
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