Are the ultrasonic parts polarity sensitive. For example will the be=20 damaged if they are connected backwards? I have a project similar to this I want to work on, but getting ranges=20 underwater but between 2 units. The transmit signal will be activated=20 by radio signal and the receiver will be hard wired. I need to find a waterproof transmitter and receiver though. Any=20 suggestions. I read somewhere that a pizeo speaker in a plastic bag might work. I plan on testing that within the next few weeks. Bob Allen Mulvey wrote: > I think this article will answer most of your questions: > http://www.micro-examples.com/public/microex-navig/doc/090-u > ltrasonic-ranger.html > > You're right about that datasheet. I've never seen one that > doesn't even give a pinout or reference circuit. > > Allen > > =20 >> -----Original Message----- >> From: piclist-bounces@mit.edu [mailto:piclist- >> bounces@mit.edu] On Behalf Of Lindy Mayfield >> Sent: Monday, October 21, 2013 2:15 PM >> To: Microcontroller discussion list - Public. >> Subject: [EE] Help understanding how these ransducers >> work >> >> After a few year hiatus I want to restart my interest in >> hobby electronics. One of the last projects that I never >> =20 > had > =20 >> time to start was a range finder. I wanted to build a >> sonar/radar. I have a 400ST/400SR pair of, for want of a >> better word, "round thingies with two wires attached." :) >> Here is a datasheet I found on the net, out of many, but >> basically they all look the same (to me). >> >> http://www.robot- >> electronics.co.uk/datasheets/t400s16.pdf >> >> I can very easily find examples how to make this work in >> practice, and I'm quite sure that I could do it just >> =20 > copying but > =20 >> not understanding. But I want to work backwards from the >> datasheet, and this particular one doesn't make sense to >> me. >> >> My EE knowledge is in the still-learning phase. The >> datasheet is nothing like I've ever seen, but here are >> =20 > some > =20 >> assumptions and questions that I am thinking of in order >> =20 > to > =20 >> at least try to figure out how to connect them up. >> >> 1) It has two leads. I cannot see in the DS where/how to >> connect them, but can I assume that one of them is ground? >> 2) In the case of the transmitter, can I assume that one >> =20 > is > =20 >> ground the other is some sort of waveform that causes it >> =20 > to > =20 >> make a sonar like sound? Like a speaker? >> 3) If so, what sort of signal? I guess PWM, and I would >> definitely try that first. I see 40Khz in the DS and that >> =20 > seems > =20 >> to point there. >> 4) Then, for the transmitter, I connect one to ground, >> another to a PIC pin generating a 40Khz PWM signal. >> >> The transmitter logically seems like a speaker of sorts, >> =20 > but > =20 >> how to connect it up with pieces parts like resistors, >> transistors, capacitors, etc still alludes me. But I'm >> =20 > willing to > =20 >> do the work to figure that part out if I have a hint where >> =20 > to > =20 >> look. >> >> The receiver seems more difficult. >> >> 1) I assume one of the 2 pins goes to ground, the other >> connected to a PIC pin. >> 2) I know that speakers also can generate an electrical >> =20 > pulse > =20 >> when connected in a certain way. I think this may be >> something like that. >> 3) Would I also be reading a PWM signal as input? But >> "what" tells me the distance? >> 4) And like the transmitter, what other pieces parts do I >> need, capacitors, op amps, resistors, etc. >> >> I'm not asking for the fish, just how to go about building >> =20 > a > =20 >> fish catching machine. :) >> >> Thanks as always, >> Lindy >> >> >> -- >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list >> archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> =20 > > > =20 --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .