I have constructed an IR motion sensor using TSOP 1238 and IR LED. I use a 555 timer to generate a 38kHz carrier frequency but the TSOP does not detect the IR signal. It still remains high! Can somebody help me with this?

 

assuming the connections are correct,is the tuned freq: correct? , u may require a fine tuning near the 38k band,

 

 

You might have a look at my webpage http://www.lpilsley.co.uk/cybot/radar.htm for a PIC based version which gives left and right indications.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

whts the average distance tht the RFID tag can be read? is it possible to increase the distance at which it can b read?

 

The IR receiver module I've used were unmarked, but work the same. They have gain control built in. Also the plastic case is IR invisible, and can pick up a signal from pretty much any direction. I had some problems on my first build, the emitter and receiver were mounted next to each other. The receiver was getting drowned out, until I put a physical barrier between them, tin foil...

Are you sure the Receiver module is working and hooked up correctly? You can hook an LED to the output pin, and use a TV remote. The LED will be on constantly, then blink when you press a button.

 

I have to admit I just copped out and bought a Sharp IR detector, like this;
HERE

Although expensive, it's reliable, easy to use and is *very* popular. It saved me hours of struggle.

 

Does the signal need modulating.......

 

thank u Mr.Harvey for the information u gave. i m just starting with RFID. collecting information to start designing it. jst nw entering the practical field, thts y i hve lots of doubts rgarding this.

 

I LOVE those Sharp sensors. From my experience they go WAY beyond their intended range...I've seen them work out past five feet! (Unless my memory is failing me they're designed for 24" maximum....)

__________________
-Ian

 

lmeenakshi, please start your own thread. This one is about Infrared modules, not RFID, which I know nothing (well almost) about. It's confusing, and a little rude (called 'Hijacking'). You should start your own topic for discussion, that way it's focused entirely on your project, unless someone else Hijacks it... It's just a good way to keep things organized here.