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shuaib
07-22-2005, 05:07 PM
:cry:
hi,
i have a problem with TSOP 1738 IR sensor...the receiver with this sensor and some BC548 transistors outputs only a peak pulse ,and then dies immediately on interrupting the IR beam .
is all TSOP 1738 's are like this or the problem with the individual piece?(or would i use some flip- flop to get continuos o/p).

maxasimo
07-22-2005, 07:20 PM
What circuit are you using...are you modulating the IR beam at 38 kHz...please provide some more details and also mention your application of TSOP

vidur
07-24-2005, 08:34 PM
Hi

The TSOP 17XX doz not have memory..

As soon as you stop the beam, the ouput will die!

So NO Beam...NO output!

If you need it to "remember" that a beam hit it... then use a flipflop

vikas
07-25-2005, 08:05 AM
Hmm yep a flip flop will be required ... try 4017 :)

addy
12-01-2005, 12:40 PM
hi......

tsop1738 gives really small distance....
atleast i nvr got the distance.....
u hav to modulat the signal.
and for memory..... use a flip flop or take inputs to a microcontroller.

boseji
01-14-2006, 07:29 PM
:cry:
hi,
i have a problem with TSOP 1738 IR sensor...the receiver with this sensor and some BC548 transistors outputs only a peak pulse ,and then dies immediately on interrupting the IR beam .
is all TSOP 1738 's are like this or the problem with the individual piece?(or would i use some flip- flop to get continuos o/p).

Hi,

The main problem that I feel is that the the current drive to the IR led thatyou are using is not much and also there is frequency shifting going on.
The frequency shifts may be cause due to the noise in the supply on due to the output Impdence of the PIn you are using for driving the IR led. Its not the problem of the IR Receiver.
Try to use a high current switing for the IR using a transtor to drive the ir led. Eg. a 2N222 in common collector config with the LED as the LOAD.

Regards,

Boseji

andig
01-26-2006, 02:00 PM
:? Hi there,

Probably you did not study the datasheet carefully. Here is some of it :

• Carrier frequency should be close to center
frequency of the bandpass (e.g. 38kHz).
• Burst length should be 10 cycles/burst or longer.
• After each burst which is between 10 cycles and 70
cycles a gap time of at least 14 cycles is neccessary.
• For each burst which is longer than 1.8ms a
corresponding gap time is necessary at some time in
the data stream. This gap time should have at least
same length as the burst.
• Up to 1400 short bursts per second can be received
continuously.

So if you are trying to continuosly sense an IR beam (for example for an interrupter type proximity switch) it will not work. The best way is to use another sensor from Siemens (I don't recall the part no. right now) that works with continuos IR. Alternative work around is to pulse the IR beam itself and checking for go/no/go if both of your circuits (Tx/Rx) works from a same board (I do this with a PIC16F676).

Let me know your exact application I will try to help. BTW I stumbled accross this forum today itself and this is my first post.

Regards

shobhitkukreti
05-01-2006, 12:29 AM
well i agree with shuaib... i am using tsop 1738 receiver and i just get peak pulses. i got an LED fixed to the reciever thru a transistor.. i even tried gettin a jk flip flop 4027 and the decade counter 4017 with it .. it dint work .. if it cud drive an led it cud sure work with these cmos ic's ... so i am still wondering bout it ..

docel
05-01-2006, 10:30 AM
well i agree with shuaib... i am using tsop 1738 receiver and i just get peak pulses. i got an LED fixed to the reciever thru a transistor.. i even tried gettin a jk flip flop 4027 and the decade counter 4017 with it .. it dint work .. if it cud drive an led it cud sure work with these cmos ic's ... so i am still wondering bout it ..

:arrow: READ andig's post again :!: