Searching \ for '[EE]: Driving Ultrasonic TX with 5V' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/io/serials.htm?key=tx
Search entire site for: 'Driving Ultrasonic TX with 5V'.

Exact match. Not showing close matches.
PICList Thread
'[EE]: Driving Ultrasonic TX with 5V'
2000\11\03@043357 by Werner Soekoe

flavicon
face
Hi

How efective would it be to drive an Ultrasonic Transmitter with 5V? I have
seen circuits using audio transformers to step up the voltage to a 20V P-P
swing, but I want to avoid this approach. I though of using a 555 to drive
the transducer directly with 5V. Will this work? I will not be using the
ultrasonic circuit for distances greater than 1m (3 feet).

Thanks!
Werner Soekoe
spam_OUTWernerSTakeThisOuTspamfsl.gov.za

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
"[PIC]:","[SX]:","[AVR]:" =uP ONLY! "[EE]:","[OT]:" =Other "[BUY]:","[AD]:" =Ads




2000\11\03@073349 by Bob Ammerman

picon face
I have used a trick to get a 10V P-P from 5V PIC on a piezo-transducer.

You can do pretty much the same thing in hardware. Just drive the two
transducer pins with 180 degree out of phase signals each swinging from 0 to
5V. (ie: one signal is the logical inversion of the other).

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

{Original Message removed}

2000\11\03@093838 by mike

flavicon
face
On Fri, 3 Nov 2000 11:38:02 +0200, you wrote:

>Hi
>
>How efective would it be to drive an Ultrasonic Transmitter with 5V? I have
>seen circuits using audio transformers to step up the voltage to a 20V P-P
>swing, but I want to avoid this approach. I though of using a 555 to drive
>the transducer directly with 5V. Will this work? I will not be using the
>ultrasonic circuit for distances greater than 1m (3 feet).
Not very. You don't need a transformer though - a simple inductor will
do. Use a common-emitter transistor switch to drive the coil , and
connect the transducer across the coil. You may need to experiment to
find the optimum coil value - I'd expect  it to be in the 1-22
millihenry range. Small axial-leaded types should work fine, and have
enough DC resistance that you won;t need a current-limiting resistor. This should give to about 20-50V drive very cheaply. For higher
voltages use a HV transistor like MPSA42.
US transducers need to be driven very close to their resonant
frequency to work well - a 555 is probably not stable enough. A
ceramic resonater, divided down would be better. You can also get
40KHz watch crystals - these are commonly used in car-alarm type U/S
applictions. If your device has a PIC in it you could use that to
generate the accurate frequency.
--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
"[PIC]:","[SX]:","[AVR]:"

2000\11\03@121616 by Robert Rolf

picon face
With a 555 and a charge pump circuit (voltage double, tripler...) (2
diodes and 2 capacitors per stage) you can generate 10, 15,20... volts
from 5, and then drive the transducer single ended (or bipolar if you
want).
I have used the Max232 to create 40V DC by hanging the voltage tripler
cct off the 10V boost capacitor. One can also use a MAX771/2/3 with and
external an switch to get 100's of volts (I use 250V in our muscle
stimulators).

My understanding of U/S piezo drivers is that you do need 10's of
volts to get any sort of range out of them. With the step up convertor
you have the ability to set your voltage at whatever you need, and
they're VERY efficient (just be sure to use large voltage divider
R's for the FB (feedback) input). Be sure to 'tune' your drive
frequency to the natural frequency of the device for maximum output.

Robert

Bob Ammerman wrote:
{Quote hidden}

> {Original Message removed}

2000\11\04@093026 by Peter L. Peres

picon face
If you drive it with 5Vpp differential you will almost not need a
preamplifier for Rx (assuming you use CMOS gates used as amplifiers). This
is for Murata 40kHz Rx/Tx. You need to tune the transmitter oscillator for
best output (measured at receiver). Without tuning you can lose 20% range.

Peter

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics




More... (looser matching)
- Last day of these posts
- In 2000 , 2001 only
- Today
- New search...