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Topic:

Topic author: aravindj36
Subject: need help
Posted on: Mar 30 2010 02:19:51 AM
Message:

Hello there, I was looking for circuit of a simple infrared light beam alarm.I dont know anything about microcontrollers .pleading help

Replies:

Reply author: Aaron Cake
Replied on: Apr 05 2010 09:45:54 AM
Message:

The simplest possible circuit is to just drive an IR LED with whatever voltage source and an appropriate dropping resistor. Then the receiving end is a phototransistor with a series resistor on the collector and the emitter to ground. Connect up the base of a transistor through another resistor to the junction of the series resistor and the collector. Now that transistor will have current pulled away from it's base as long as the photo transistor receives light. Stick an IR filter on it and a tube to make it directional. That's about as simple as you can get. Your alarm is switched by the second transistor which stays off as long as the phototransistor receives light.

Reply author: aravindj36
Replied on: Apr 10 2010 05:20:07 AM
Message:

I also got that idea but ir phototransistors and photdiodes are very hard to get in my place.But tsop modules are available I even have a few tsop1838's with me . And now i'am looking for an ir detector which when detects coded ir light makes an led glow but not blink the problem with normal circuits are that the led blinks when it detects ir light.Please help me aaron

Reply author: Aaron Cake
Replied on: Apr 11 2010 10:27:46 AM
Message:

I don't know what a TSOP module is.

There isn't an electronics store in all of India?

Reply author: audioguru
Replied on: Apr 11 2010 1:01:31 PM
Message:

A TSOPxxx is an IR receiver IC that is made by Vishay/Telefunken.
It has a black coated photo-diode, amplifier, tuned filter, AGC, Demodulator and output transistor.

Download Attachment: TSOP IR receiver.PNG
29.03 KB

Reply author: aravindj36
Replied on: Apr 20 2010 12:51:11 AM
Message:

Atlast after a lot of searching I got the photransistor 2n5777.Could you please give the circuit rather than explaining it please!!!!!!!!!!!!!!!

Reply author: aravindj36
Replied on: Apr 20 2010 06:22:24 AM
Message:

Now I think buying the phototransistor was a waste of 40RS as I found this circuit http://www.circuitstoday.com/infrared-intrusion-barrier And now my question is whether i can use an in4148 insted of the bat28 diode

Reply author: pebe
Replied on: Apr 20 2010 09:50:49 AM
Message:

It's difficult to see how IC2 of the receiver can oscillate.

Reply author: aravindj36
Replied on: Apr 21 2010 05:03:00 AM
Message:

Iam not planning to use the transmitter circuit instead iam going to use a remote control

Reply author: audioguru
Replied on: Apr 21 2010 11:58:20 AM
Message:

The receiver circuit is wrong and will not work. But can't find a modern BAT85 Schottky diode for it anyway.

Reply author: aravindj36
Replied on: Apr 22 2010 12:58:16 AM
Message:

Then can anybody give me a correct circuit of the thing PLEASE!!!!!!!!!!!!!!!!!!!!!!!!!!

Reply author: audioguru
Replied on: Apr 22 2010 3:49:00 PM
Message:

The internet has thousands of IR circuits that do not work and it has thousands of IR circuits that work perfetly.
If this is a school project then your teacher wants you to study them and select a circuit that works.

Reply author: aravindj36
Replied on: Apr 29 2010 06:04:12 AM
Message:

I found this circuit.will this work http://home.cogeco.ca/~rpaisley4/IrProximity.html

Reply author: audioguru
Replied on: Apr 29 2010 11:46:21 AM
Message:

In the new circuit the voltage comparator will not work because its output is missing a pullup resistor.

Reply author: aravindj36
Replied on: May 01 2010 04:02:47 AM
Message:

will this one work http://www.b-kainka.de/bast323.jpg

Reply author: pebe
Replied on: May 01 2010 07:24:41 AM
Message:

Is the symbol marked "100mA" supposed to represent a lamp?

Reply author: audioguru
Replied on: May 01 2010 12:50:32 PM
Message:

Your new circuit will not work unless you remove the diode.
The 36kHz carrier for the IR pulses must be modulated in "bursts" (explained in the datasheet)for good range.

Why are most circuits posted on the internet WRONG?

Reply author: aravindj36
Replied on: May 02 2010 09:08:33 AM
Message:

Well i dont know why .could anyone give me a working cicuit ithink its been too long since the post began.And now i've managed to get an L14F1
phototransistor giving 60Rs (today 1 us$=Rs50).For me thats too much but a tsop1838 costs me just Rs10

Reply author: aravindj36
Replied on: May 04 2010 05:31:13 AM
Message:

will this work http://www.shreeramindia.com/kits_n_spares/electronics%20projects/Electronic%20Watchdog.htm

Reply author: audioguru
Replied on: May 04 2010 10:21:33 AM
Message:

Most circuits from that website in India are very old and do not work or work very poorly.
The IR transmitter does not send bursts of 38kHz pulses so the TSOP IR receiver turns down its gain and then the range is very small. It needs another 555 oscillator to create the bursts.

Reply author: aravindj36
Replied on: May 05 2010 11:38:10 AM
Message:

well then is their any way i can create a continuos non fluctuating pulse from the tsop so that i could configure it as a potential divider and drive a relay

Reply author: audioguru
Replied on: May 05 2010 6:43:38 PM
Message:

An IR receiver IC is made to give an output of varying pulses from the varying pulses from a remote control transmitter. Since you want a non-fluctuating DC output then your receiver circuit must include a mono-stable multivibrator or a flip-flop latch.

Reply author: aravindj36
Replied on: May 09 2010 02:25:25 AM
Message:

In the given circuit will the input given to pin no 11 be a stable one http://www.dsaprojects.110mb.com/electronics/ir/ir-1_sch.gif

Reply author: audioguru
Replied on: May 09 2010 11:38:32 AM
Message:

The link to your schematic does not work.

Reply author: aravindj36
Replied on: May 16 2010 07:05:50 AM
Message:

OK then from which all pins of the circuit from shreeram give me a continuos signal forget the tx

Reply author: aravindj36
Replied on: May 16 2010 07:30:16 AM
Message:

Reply author: audioguru
Replied on: May 16 2010 09:11:06 AM
Message:

Who is Sheeram?
Your links do not work.

Reply author: aravindj36
Replied on: May 17 2010 02:28:08 AM
Message:

Not someone it is the link i had given earlier it starts shreeram electronics

Reply author: pebe
Replied on: May 17 2010 04:22:24 AM
Message:

quote:
Originally posted by aravindj36

Not someone it is the link i had given earlier it starts shreeram electronics

ALL of your links are to websites. None of them refer to a circuit.

Reply author: aravindj36
Replied on: May 24 2010 01:54:13 AM
Message:

ok will this work http://home.cogeco.ca/~rpaisley4/IRProxOscReceiver.GIF and please which one of the 2 circuits are better

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