Clarification Ultrasonic Sensors..!!! - Electronic Circuits Projects Diagrams Free

maheshcet · 20th September 2007, 04:53 PM

Hi... i am working on a robotics project which involves obstacle detection... planned to use ultrasonic sensors.. purchased them too... i tested the transmitter and receiver circuit... the receiver side not workin... i am lukin for another transmitter and receiver circuit ... which will work for sure...
please reply as soon as possible... need to submit the project within 1 week...!!!

Hero999 · 20th September 2007, 05:20 PM

Please post the circuit that didn't work and we might be able to help you get it working.

maheshcet · 20th September 2007, 05:23 PM

maheshcet · 20th September 2007, 05:27 PM

i have posted the circuit i have used.. please do help..!!!

maheshcet · 20th September 2007, 05:29 PM

Hero999 · 20th September 2007, 06:28 PM

What do you mean it doesn't work?

Does the relay remain energised all the time or does it not energise when the transmitter is activated?

How do you know it's the reciever that's not working and not the transmitter?

What are you using for the speaker? Is it a piezo tweeter, 8

dynamic tweeter or a piezo transducer?

The reciever won't work with an 8

dynamic tweeter, it needs to be a piezo, unless you add DC blocking capacitor.

I don't see the point of having T1 and T2 as booster transistors then having R5 and R4 limit the current, you might as well drive it directly from the 555 and remove D1, D2, T1 and T2.

maheshcet · 21st September 2007, 05:31 AM

can u give me an alternate workin circuit... i am less experienced with the sensor parts....!!!!

Hero999 · 21st September 2007, 01:24 PM

Even if I had the circuit in front of me I still couldn't do that because I don't know what sort of sensor and transmitter you're using.

Can you please post pictures of them or catalogue numbers?

sv_shady · 24th September 2007, 08:14 AM

Hi, this is the circuit I have designed and it surely works.

The receiver circuit consists an OP-amp, LM567 (which is a frequency filter), and LM393 (comparator, to avoid false triggering) The circuit operation is very simple - send +5v on pin4 (send ultrasonic sound) for about 200us and start a timer, then wait for pin5 (receive ultrasonic sound) to become high, then stop and read the timer. Multiply the time by the speed of sound, then divide by 2 and here is the distance. The only posible problem is that you can't afford to supply +12V for the ultrasound transmitter there are 2 ways to solve that problem:
#1 Use 5v but the range of the transmitter will decrease dramatically
#2 Use MAX232 and from 5v you'll have around 16v (-8v and +8v)

I hope this will help u

**Nigel Goodwin** · 24th September 2007, 08:27 AM

My first thought is the lack of filtering on the receiver?.

It could be easily improved by limiting the frequency response of the two amplifier stages (by adding low pass and highpass filters).

audioguru · 24th September 2007, 05:05 PM

The old LM358 dual opamp has dificulty amplifying frequencies over only 6kHz. It is not suitable for ultrasonic frequencies.

The old LM358 dual opamps are shown with positive feedback instead of negative feedback so they won't amplify anything anyway.

Hero999 · 24th September 2007, 05:53 PM

That's right, they'll act as comparators.

mcs51mc · 24th September 2007, 06:04 PM

Ultrasonic you said?
Use the search function on this forum
Lot's of hits

One written by myself

Never the less, if it's for "normal environment" take a look at this site http://www.interq.or.jp/japan/se-inoue/e_pic6_6.htm you will find all you need on US systems with very clear explanation on transmitter, receiver detection, ...

Sorry to repeat myself

sv_shady · 26th September 2007, 03:48 PM

@Nigel Goodwin There is filtering - LM567, you should read first.
LM358 works perfectly in the circuit, the measurments are exactly as if they were in the book

Test the circuit and let me know the results.

**Nigel Goodwin** · 26th September 2007, 04:05 PM

Quote:

Originally Posted by sv_shady

@Nigel Goodwin There is filtering - LM567, you should read first.

No, the 567 is a tone detector, NOT a filter - by the simple addition of a few capacitors to filter the incoming signal performance would be enhanced. The 567 will only detect the one specific frequency (+/- ?%), but will be helped by not feeding it lots of rubbish.

And like Audioguru says, using a better opamp would help immensely as well.

20th September 2007, 04:53 PM	(permalink)
maheshcet New Member	Clarification Ultrasonic Sensors..!!! Hi... i am working on a robotics project which involves obstacle detection... planned to use ultrasonic sensors.. purchased them too... i tested the transmitter and receiver circuit... the receiver side not workin... i am lukin for another transmitter and receiver circuit ... which will work for sure... please reply as soon as possible... need to submit the project within 1 week...!!!

20th September 2007, 05:20 PM	(permalink)
Hero999 Experienced Member	Please post the circuit that didn't work and we might be able to help you get it working. __________________ What's so bad about Microsoft? Get Opera it's simply a superb browser.

20th September 2007, 05:23 PM	(permalink)
maheshcet New Member	Last edited by maheshcet; 20th September 2007 at 05:25 PM.

20th September 2007, 06:28 PM	(permalink)
Hero999 Experienced Member	What do you mean it doesn't work? Does the relay remain energised all the time or does it not energise when the transmitter is activated? How do you know it's the reciever that's not working and not the transmitter? What are you using for the speaker? Is it a piezo tweeter, 8 dynamic tweeter or a piezo transducer? The reciever won't work with an 8 dynamic tweeter, it needs to be a piezo, unless you add DC blocking capacitor. I don't see the point of having T1 and T2 as booster transistors then having R5 and R4 limit the current, you might as well drive it directly from the 555 and remove D1, D2, T1 and T2. __________________ What's so bad about Microsoft? Get Opera it's simply a superb browser.

21st September 2007, 01:24 PM	(permalink)
Hero999 Experienced Member	Even if I had the circuit in front of me I still couldn't do that because I don't know what sort of sensor and transmitter you're using. Can you please post pictures of them or catalogue numbers? __________________ What's so bad about Microsoft? Get Opera it's simply a superb browser.

20th September 2007, 05:27 PM	(permalink)
maheshcet New Member	i have posted the circuit i have used.. please do help..!!!

20th September 2007, 05:29 PM	(permalink)
maheshcet New Member

21st September 2007, 05:31 AM	(permalink)
maheshcet New Member	can u give me an alternate workin circuit... i am less experienced with the sensor parts....!!!!

24th September 2007, 08:14 AM	(permalink)
sv_shady New Member	Hi, this is the circuit I have designed and it surely works. The receiver circuit consists an OP-amp, LM567 (which is a frequency filter), and LM393 (comparator, to avoid false triggering) The circuit operation is very simple - send +5v on pin4 (send ultrasonic sound) for about 200us and start a timer, then wait for pin5 (receive ultrasonic sound) to become high, then stop and read the timer. Multiply the time by the speed of sound, then divide by 2 and here is the distance. The only posible problem is that you can't afford to supply +12V for the ultrasound transmitter there are 2 ways to solve that problem: #1 Use 5v but the range of the transmitter will decrease dramatically #2 Use MAX232 and from 5v you'll have around 16v (-8v and +8v) I hope this will help u

24th September 2007, 08:27 AM	(permalink)
Nigel Goodwin Super Moderator	My first thought is the lack of filtering on the receiver?. It could be easily improved by limiting the frequency response of the two amplifier stages (by adding low pass and highpass filters). __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

24th September 2007, 05:05 PM	(permalink)
audioguru Experienced Member	The old LM358 dual opamp has dificulty amplifying frequencies over only 6kHz. It is not suitable for ultrasonic frequencies. The old LM358 dual opamps are shown with positive feedback instead of negative feedback so they won't amplify anything anyway. __________________ Uncle $crooge

24th September 2007, 05:53 PM	(permalink)
Hero999 Experienced Member	That's right, they'll act as comparators. __________________ What's so bad about Microsoft? Get Opera it's simply a superb browser.

24th September 2007, 06:04 PM	(permalink)
mcs51mc Experienced Member	Ultrasonic you said? Use the search function on this forum Lot's of hits One written by myself Never the less, if it's for "normal environment" take a look at this site http://www.interq.or.jp/japan/se-inoue/e_pic6_6.htm you will find all you need on US systems with very clear explanation on transmitter, receiver detection, ... Sorry to repeat myself

26th September 2007, 03:48 PM	(permalink)
sv_shady New Member	@Nigel Goodwin There is filtering - LM567, you should read first. LM358 works perfectly in the circuit, the measurments are exactly as if they were in the book Test the circuit and let me know the results. Last edited by sv_shady; 26th September 2007 at 03:51 PM.

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