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arduino tvbgone project, why current through ir leds is so l
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arduino tvbgone project, why current through ir leds is so l

by kashi786 on Sat Dec 01, 2018 8:16 am

I am doing this project on arduino nano, I got the code of it online. Just FYI I don't have problem with range, but I am curious why is the current through ir leds so low. The IR leds are rated for 100ma, and according to my circuit, the current should be like 150ma through the leds but when I check on multimeter, it is usually showing varying pulses like 5ma, 10ma, the most it goes is like 20ma. But I added another couple of lines, another code(function) basically to this project of 38khz frequency to jam tv remotes, and when I switch to that code, function, my current shoots upto the steady 100-150ma that it should be according to my circuit whereas with the tvbgone, it shows very reduced current that keeps changing with the pulses. so my question is why is it showing such low current?? Is it only for me or is it like this for other devices??


Someone on youtube said you need scope to see the high current since the frequency is so high, so then why is that not the case for the remote jammer code since that is also like same frequency

kashi786
 
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Re: arduino tvbgone project, why current through ir leds is

by adafruit_support_bill on Sat Dec 01, 2018 11:01 am

The TVbgone output is a series of pulses modulated by the carrier frequency. https://learn.adafruit.com/tv-b-gone-ki ... r-code-9-5
The multimeter is going to give you an average reading. Most integrate over a few hundred ms at least.

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Re: arduino tvbgone project, why current through ir leds is

by kashi786 on Sun Dec 02, 2018 1:14 am

So why does it show high current for this code, this is also sending sending pulses on same frequency??

// TV REMOTE JAMMER

//This is a Daniyal Shamsi program in which an ir led is placed

//on pin 12 and is kept near tv,and it blocks the tv remote signals...

int irled = 12;

void setup() { pinMode(irled, OUTPUT);

}

void loop() {

digitalWrite(irled, HIGH);

delayMicroseconds(12);

digitalWrite(irled, LOW);

delayMicroseconds(12);

}

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Re: arduino tvbgone project, why current through ir leds is

by adafruit_support_bill on Sun Dec 02, 2018 8:21 am

Probably because the average duty cycle for the TVBgone pulses is less than the 50% you have in your test code. You would really need to look at it with an oscilloscope to see what pulses are being sent.

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Please be positive and constructive with your questions and comments.