Ultra sonic Transducer

[King_of_the_sky]

Hi im doing a school project and i need to find out what sort of range an
ultra sonic transducer transmitter/reveiver from the rapid electronics
catalog is outside.

Thaks Paul

 

[Anthony Fremont]

"King_of_the_sky" wrote:

Hi im doing a school project and i need to find out what sort of range
an
ultra sonic transducer transmitter/reveiver from the rapid electronics
catalog is outside.

If you're talking about the ones that www.rapidelectronics.co.uk have,
the cheap small one
http://www.rapidelectronics.co.uk/security_43-0254.htm would be
virtually useless outside. It appears that is intended for a security
device covering a small space.

The more expensive and larger one
http://www.rapidelectronics.co.uk/best_77-2642.htm would give you maybe
20' of range. You could build your own that could be made to have a
longer range (maybe double?) buy using an "industrial strength"
transducer. You may need to drive it with 150V or so. This is not as
bad as it sounds, as you only need to generate the high voltage for
short durations and at very small current, so you can use a battery
supply. This can be done in different ways usually involving
oscillators and inductors of some sort.

 

[Graham W]

Anthony Fremont wrote:

"King_of_the_sky" wrote:
Hi im doing a school project and i need to find out what sort of
range an ultra sonic transducer transmitter/reveiver from the rapid
electronics catalog is outside.

If you're talking about the ones that www.rapidelectronics.co.uk have,
the cheap small one
http://www.rapidelectronics.co.uk/security_43-0254.htm would be
virtually useless outside. It appears that is intended for a security
device covering a small space.

The more expensive and larger one
http://www.rapidelectronics.co.uk/best_77-2642.htm would give you
maybe 20' of range. You could build your own that could be made to
have a longer range (maybe double?) buy using an "industrial strength"
transducer. You may need to drive it with 150V or so. This is not as
bad as it sounds, as you only need to generate the high voltage for
short durations and at very small current, so you can use a battery
supply. This can be done in different ways usually involving
oscillators and inductors of some sort.

Having noted all that, you are not in control of the environmental noise
and all sorts of things may upset your system with noise pulses that
you yourself cannot hear.

Early TV remotes working on ultrasound were easily upset by
bunches of keys being picked up/put down/jangled and even
by the name tag on the dog's collar when he shook his head or
had a scratch!


--
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Change 'news' to 'sewn' in my Reply address to avoid my spam filter.

 

[Anthony Fremont]

Graham W wrote:

Anthony Fremont wrote:
snip
The more expensive and larger one
http://www.rapidelectronics.co.uk/best_77-2642.htm would give you
maybe 20' of range. You could build your own that could be made to
have a longer range (maybe double?) buy using an "industrial
strength" transducer. You may need to drive it with 150V or so.
This is not as bad as it sounds, as you only need to generate the
high voltage for short durations and at very small current, so you
can use a battery supply. This can be done in different ways
usually involving oscillators and inductors of some sort.

Having noted all that, you are not in control of the environmental
noise and all sorts of things may upset your system with noise pulses
that you yourself cannot hear.

Early TV remotes working on ultrasound were easily upset by
bunches of keys being picked up/put down/jangled and even
by the name tag on the dog's collar when he shook his head or
had a scratch!

IME, I've found that the transducer that I worked with was fairly
insensitive to frequencies that weren't extremely close to the resonant
freq. of the transducer. Also, by only paying attention to the
transducer during a narrow window of time, you help to minimized false
readings. If extreme accuracy is not necessary, you could modulate the
signal. Of course it's never going to be perfect, as no system is. ;-)