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| Electronic Projects Design/Ideas/Reviews Are you building an electronic project or want to? Maybe you need some assistance? Come and submit your electronic questions here and let our experienced members find a solution. |
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6th March 2008, 04:31 PM
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 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. | |
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6th March 2008, 04:31 PM
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6th March 2008, 04:45 PM
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| 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.
__________________ Uncle $crooge | |
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6th March 2008, 04:50 PM
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| 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? | |
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6th March 2008, 05:11 PM
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| Thanks alot for all | |
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6th March 2008, 05:14 PM
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| Why are you saying that?! Thank you any way! | |
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6th March 2008, 05:16 PM
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| 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.
__________________ Uncle $crooge | |
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9th March 2008, 07:03 PM
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| 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. | |
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9th March 2008, 07:06 PM
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5th April 2008, 03:13 PM
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| 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 | |
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6th April 2008, 06:14 PM
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| Why don't you email the author of the circuit, his email in on the site. | |
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7th April 2008, 02:29 AM
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| 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:
__________________ Uncle $crooge | |
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11th April 2008, 05:20 PM
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| 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. | |
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14th May 2008, 10:01 AM
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| 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 | |
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14th May 2008, 10:05 AM
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| 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. | |
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