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DPRG: Multiple Sonar

Subject: DPRG: Multiple Sonar
From: Daniel Herrington Daniel.Herrington at nsc.com
Date: Wed Mar 24 11:57:33 CST 1999

James,

I'd probably try some cheap reed relays.  Just make sure you allow
enough time for contact bounce to die out upon switching the relays
to do the next ping.

Mouser's got some reed relays with the following specs:

>from page 301:

HIGH RELIABILITY REED RELAYS
Form A SPST Contacts Normally Open
Contact Resistance:	150mOhm (max)
Operate time:		1.0ms (max)
Release time:		0.5ms (max)
Dielectric strength:	200VDC for 1 minute between contacts
Current rating:		not listed
Coil Volts:		5.0, 12.0VDC available
Coil Resistance:	250, 500, 1050 Ohm available
Price:			$1.84 ea.


I don't know whether or not the 200VDC is enough, if you're using the
Polaroid transducers.  Also the 2A current may be a problem.  You
might get a couple and do some reliability testing.

By the way, make sure you twist the pair of wires that goes to each
transducer so you don't lose signal strength due to EMI.  And use at
least the same gauge of wire that originally came with the
transducers, if not larger.

Regards,
   Daniel


=> Replying to Dan Miner's message, "RE: DPRG: Multiple Sonar " (Mar 24):
 > Hmmm... That's an option I hadn't considered.
 > DrilBert uses 2 driver boards with its 2 transducers.
 > 
 > Let me (and the list) know what you find out...
 > 
 > 				- Dan
 > 
 > > -----Original Message-----
 > > From: James Vroman [mailto:vroman at tech-tools.com]
 > > Sent: Wednesday, March 24, 1999 8:02 AM
 > > To: dprglist at dprg.org
 > > Subject: DPRG: Multiple Sonar 
 > > 
 > > 
 > > I am trying to find out information on the best way to switch between 
 > > multiple sonar transducers on one driver board. I have found 
 > > references 
 > > on the web to using relays and opto-fets.
 > > Any ideas or recommendations.
 > > 
 > > James Vroman - TechTools
 > > EMAIL: vroman at tech-tools.com
 > > Phone:(972)272-9392
 > > FAX: (972)494-5814
 > > 
 > 

- -- 
Daniel Herrington
National Semiconductor Corp.
email: Daniel.Herrington at nsc.com
phone: (817)468-6684

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