Need help>> as soon as possible!

[Abeer_engjbr]

Hi
I connected the IR Repeater circuit part by part but:
1) The Led that must be off for testing was on with no input ( Why is that?)

2) The oscillator has no clear signal on the screan ( I connected it on the 2.2k resistor), but when I point the ir signal at the photodiode as I get closer to it the amplitude became larger.

3) I know that the function of the photodiode is to convert ir signal to current in order to deal with it in an electronic way rather than electromagnetic way, but , on the hand when I tryed to measure the current that is passing through 3.3k resistor , there was a very small reading (0.006mA) after pointing the ir signal , is that true? or does this indicates that the photodiode does not work properly? How can I test a photodiode?

Please Answer ASAP, I need to try your suggestions.
Thanks.

 

[Abeer_engjbr]

The Link Is

http://english.cxem.net/infrared/ir7.php

 

[audioguru]

The circuit does not have a photo-diode. A photo-diode has two wires.
The circuit has a TSOP1738 IR receiver IC. It has three wires.
Maybe you used a photo-transistor that has three wires and would cause your symptom.

The output of the IR receiver IC is high when it does not receive a signal. Then the first transistor is turned on which resets the 555 so it does not run and makes its output low so the output transistor does not turn on the LEDs.

 

[Abeer_engjbr]

I used a TSOP1738, I bought it specificaly last week, maybe i said photodiode but i ment TSOP1738 IC, any way i need to know why i the Led on when i test the circuit directly after i connect the 12 V to the circuit, What should I do to test the 3 stages?

 

[aliali88]

Thanks alot for all

 

[Abeer_engjbr]

Why are you saying that?! Thank you any way!

 

[audioguru]

Start testing at the output:
1) Connect the base of the output transistor to 0V and the LEDs should turn off.
2) Connect pin 4 (RST) of the 555 to 0V and the LEDs should turn off.

Maybe you connected the pins of the TSOP backwards.
Maybe you connected the zener diode backwards so it produces 0.7V instead of 5.1V.
Maybe you connected the pins of the transistors backwards.

 

[Abeer_engjbr]

Hello For All,
I Have constructed The Ir Tester circuit but it dii not work, the led must be on when recieving the ir signal, but it didn't! what is the reason you think? and is there any other circuits that i can know the power of the IR signal comming from mobile ( as it was my goal from the tester circuit), please advise me for what's best to do.

 

[Abeer_engjbr]

The Link is
https://www.electronics-lab.com/projects/test/003/
Thx.

 

[Abeer_engjbr]

Help

Hello everyone,

Once again I'am here trying to get advise from you, hoping that you may be able to help me.

The IR Repeater circuit I constructe worked, but in only 2 first stages, meaning it catched the ir light and the 555 timer made 38kHz and the output resistor had sequere pulses when sening the signal, but the led didnot flash and the IR leds didnot retransmitte the ir signal...

May be the reasone is when I took the circuit home to try it in front of the TV , I bought 12 dc voltage battery(TOPCO) it is supply by electricity, any way I have DMM at my place and when I measured the voltage it was 18V without a load and 16.5V when i connect it to the circuit , and I measured the IN pin voltage of the voltage regulator , it was 10.5V , but it must be 12 volt in order for the circuit to work, is it why the IR transmitter didnot work?
should i connect 6V batteries in series without the Voltage regulator?

How can i know the polarity of the IR leds? and I used BC549B instead of
BC549C , and C33725 instead of BC337 , does it make a difference in the circuit or why it did not work probilbly?

The circuit is in:
http://english.cxem.net/infrared/ir7.php

Please help me

 

[blueroomelectronics]

Why don't you email the author of the circuit, his email in on the site.

 

[audioguru]

All of your circuit works except the LEDs.
Maybe the pins on the LEDs are connected backwards.

The output of the 555 is fine but maybe the pins on the BC337 are connected backwards.
Here is how they are shown on the datasheet:

 

[Abeer_engjbr]

Thank you all for your time, especaily audioguru.

I finally completed my graduating project and now I am able to control TV from a good distance using mobile phone as a remote control.

 

[Abeer_engjbr]

important

Hi everyone,
I need to know why there is two IR Leds in the following circuit ? and if I used only one would it make a difference?
Thanks.
The link is:
http://english.cxem.net/infrared/ir7.php

 

[Nigel Goodwin]

Two give twice the power output of one, with no extra current required. You could replace it with one, but you would need to recalculate the series resistor, and output would be halved.

 

[Abeer_engjbr]

Thanks but I didn't understood your second sentence:
You could replace it with one, but you would need to recalculate the series resistor, and output would be halved.
I thought that it is used to increase the coverage distance, isn't it?
Another thing, does each one send the same pluses at the same time , or the pulses is spreaded for the two of them?

when there is no signal, i know the input of the ir recevier is high so the BC549c will be on , the collector voltage will be low why? and how is that can anyone explain a littil bit..

 

[arhi]

You could replace it with one, but you would need to recalculate the series resistor, and output would be halved.

If you remove one IR LED, the current trough the other one would be too high, so you need to increase R7 in order to limit current trough IR LED.

I thought that it is used to increase the coverage distance, isn't it?

yes, with two led's you have more IR light hence more distance

Another thing, does each one send the same pluses at the same time , or the pulses is spreaded for the two of them?

yes, they send identical impulses if connected as presented in schematic

 

[arhi]

when there is no signal, i know the input of the ir recevier is high so the BC549c will be on , the collector voltage will be low why? and how is that can anyone explain a littil bit..

The IR Receiver is trigering RESET port of the oscillator via transistor. When the IR Receiver detect signal, it will release oscillator and oscillator will generate signal. when there is no signal, it will hold the oscilator. If that is not clear, check out the data sheet of ne555

 

[Nigel Goodwin]

Thanks but I didn't understood your second sentence:
You could replace it with one, but you would need to recalculate the series resistor, and output would be halved.
I thought that it is used to increase the coverage distance, isn't it?
Another thing, does each one send the same pluses at the same time , or the pulses is spreaded for the two of them?

They are in series, so both obviously transmit the same thing at the same time - it's common practice in remote controls to use two LED's.

 

[Abeer_engjbr]

i need to know what is the purpose of the 10 kohm resistor at the input stage, thanks.

http://english.cxem.net/infrared/ir7.php