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Lizard NDE Ltd- Home of the Lizard FGI electro-magnetic array technology

555 views
05:50 Oct-12-1999

CCChong

Student
University Of Manchester,
United Kingdom,
Joined Oct 1999
1
ULTRASONIC DATA LINK (ULTRASONIC WIRELESS MOUSE)

My main objective is to design an ultrasonic data link that capable of transparently conveying a low speed binary data signal over a range of few metres (eg.3-4m) with data rates in the region of 2000bits/s.

My second objective is to demonstate the utility of the ultrasonic data communication link by allowing a PC to communicate with its mouse.(ie. wireless PC/mouse interface)

Ultrasonic transducers I am going to use can transmit and receive ultrasonic signals at frequencies of ~40kHz.Following are the specifications for the transducers:

T40-16 R40-16
Transmitter Receiver
Sensitivity (dB) 17±6* -56±6#
Resonant freq. (kHz) 40±1 40±1
Max. input (Vrms) 7 -
Impedance (ohm) approx 200 70k
Capacitance (pF) ±20% 1400 1400
Pulse rise time (msec) 2 0· 5
Max input voltage, pulse
operation: 60V p-p -

* 0dB = 1µBar/V/m
# 0dB = 1V/µBar with 47k shunt
Overall size 15mm dia x 12mm deep (connecting pins protrude a further 9mm) Pins are 10mm apart.


I really I can get some ideas,advices and useful information for my project.The major problem now is what type of method should I use to transmit the digital signal to the receiver in such a narrow bandwidth avaiable??Should I used a microcontroller for this??

PLease provide me with information.I really need helps!!!

Thank you very much.

CCC




 
01:26 Oct-12-1999
Wieslaw Bicz
Re: ULTRASONIC DATA LINK (ULTRASONIC WIRELESS MOUSE) 2 0· 5
: Max input voltage, pulse
: operation: 60V p-p -

: * 0dB = 1µBar/V/m
: # 0dB = 1V/µBar with 47k shunt
: Overall size 15mm dia x 12mm deep (connecting pins protrude a further 9mm) Pins are 10mm apart.

:
: I really I can get some ideas,advices and useful information for my project.The major problem now is what type of method should I use to transmit the digital signal to the receiver in such a narrow bandwidth avaiable??Should I used a microcontroller for this??

: PLease provide me with information.I really need helps!!!

I think, it will be possible to make such link, and it could have some
advantages in comparison with other devices of this kind.

I also think, you will need to use higher frequencies and it will be probably
necessary to design special transducers and a driver for it.

If you are interested in it, we can offer you our cooperation.





 
04:17 Jan-12-2000
Earle Clark
Re: ULTRASONIC DATA LINK (ULTRASONIC WIRELESS MOUSE) Try using a ball on a floating plane transmitting to a receiver! Get away from the "Mouse" and work with the fingers! The ball, conveys the direction of the curser and a pad on either side can transmit a pulse from a pat ..so you may have a flat object in front of the computer..moving the curser (minus the mouse tail) freely! Enhance the transmission..and you can walk aroung the room with a "clip board" and do your screen adjustments!

Just a thought!

Earle sends to you!

: My main objective is to design an ultrasonic data link that capable of transparently conveying a low speed binary data signal over a range of few metres (eg.3-4m) with data rates in the region of 2000bits/s.

: My second objective is to demonstate the utility of the ultrasonic data communication link by allowing a PC to communicate with its mouse.(ie. wireless PC/mouse interface)

: Ultrasonic transducers I am going to use can transmit and receive ultrasonic signals at frequencies of ~40kHz.Following are the specifications for the transducers:

: T40-16 R40-16
: Transmitter Receiver
: Sensitivity (dB) 17±6* -56±6#
: Resonant freq. (kHz) 40±1 40±1
: Max. input (Vrms) 7 -
: Impedance (ohm) approx 200 70k
: Capacitance (pF) ±20% 1400 1400
: Pulse rise time (msec) 2 0· 5
: Max input voltage, pulse
: operation: 60V p-p -

: * 0dB = 1µBar/V/m
: # 0dB = 1V/µBar with 47k shunt
: Overall size 15mm dia x 12mm deep (connecting pins protrude a further 9mm) Pins are 10mm apart.

:
: I really I can get some ideas,advices and useful information for my project.The major problem now is what type of method should I use to transmit the digital signal to the receiver in such a narrow bandwidth avaiable??Should I used a microcontroller for this??

: PLease provide me with information.I really need helps!!!

: Thank you very much.

: CCC




 
05:54 May-23-2000
tongfeng
Re: ULTRASONIC DATA LINK (ULTRASONIC WIRELESS MOUSE)
Maybe you can try two methods.
The one,you can using a transducer equalizer,that can widen the bandwith of transducer.For example,a FIR
filter can do it.You first train its weights by a ideal
signal,then when inputing real signal,the output is
equalized.That is,the bandwith of system is widened.
Another idea,I think,you can employ FM method.Using
PLL to modulate and de-modulat,realization of 2000bps is not difficult.

tongfeng




 


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