It depends where you're going to be using it. If you're going to be using it inside a building or room, then you can count on getting a continuous radar signal back from the walls (especially if they're metal), and you can just look for "holes" in that signal when a person comes in.

If you want to do it that way, go with a wavelength (and transmit power) of radar that is obviously safe to use around humans, but also is readily absorbed by water. That would probably be the easiest way to do it, although you couldn't get distance, you'd just get a "something's in here, at approximately 120 degrees from North (or some set point)" return.

 

Paul Obrien

Yes the transmitter doesn't seem to be connected to the rest of the circuit. Since the transmitter is free-running maybe the receiver locks to the transmitter, can't say I've studied it that closely. Maybe I'll build one and see what happens!

 

Paul Obrien

OK, after some quick cct browsing it looks like the 74AS04 is made into 2 osc, 1 transmit and 1 receive, I haven't done the figures but the transmit side looks asymetrical ie longer on/off. The receiver diode output goes HIGH when active.The receiver with the AND wired as non-inverting buffer thru the series resonate cct (which would also delay the signal) then mixed with an inverted (non delayed) signal would produce very brief pulses. This would go The output is then fed to an integrator and that signal fed thru a comparator into an AND gate with the receive osc. 74AS160 BCD DECADE COUNTER being clocked by the local osc until a pulse from the receive cct. I'll have to have a look in my OLD data books for the 74AS160 to get a better understanding. I don't like the timebase but it is cheap and so long as you don't have to take the results to court and you can calibrate it somehow, it could be fun.

 

Paul Obrien

ALERT, I have just seen an ad for the Mattel Hot Wheels Radar Gun for AUS$30, I have googled looking for some better description but to no avail.
I therefore can't say if it's optical or RF but since it's designed to be aimed at very small cars maybe optical.

 

The receiver diode is forward biased all the time, so the logic following it will do nothing.

__________________
Uncle $crooge

 

Isn't it interesting that there is no difference between optical and RF in the eyes of physics?

 

Paul Obrien

Yes, about 15years ago I helped the Customs people here identify a Luneberg Lens which had been dislodged from a buoy. The distinction between RF and optic really does get blurred.

 

pls send me simple and economic circuits for radar system

 

Where shall we send it to?

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com/

 

pls send me simple and economic circuit and corresponding idea to mailmedvimalraj@gmail.com

 

What range do you want your Radar?

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com/

 

sorry friends

i have droped that projects .

but will u provide me informations about data tranmitter and reciever modules .for about 300 mtr range.

it is not a vedio transmition but ony 8bit datas.

so pls send me the information about this to my id mailmedvimalraj@gmail.com