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| Lets pretend we have a Sony remote, and we can look at exactly what light is being blasted out of the IR LED. We'll hookup a basic light sensor (like a basic photocell!) and listen in. We won't use a decoder like a PNA4602 (just yet) because we want to see the undecoded signal. What we see is the following: | | Lets pretend we have a Sony remote, and we can look at exactly what light is being blasted out of the IR LED. We'll hookup a basic light sensor (like a basic photocell!) and listen in. We won't use a decoder like a PNA4602 (just yet) because we want to see the undecoded signal. What we see is the following: |
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− | [[Fichier:IR-SIGNAL-1.jpg]] | + | [[Fichier:IR-SIGNAL-1.jpg|400px]] |
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| Basically we see pulses or IR signal. the yellow 'blocks' are when the IR LED is transmitting and when there is only a line, the IR LED is off. (Note that the voltage being at 3VDC is just because of the way I hooked up the sensor, if I had swapped the pullup for a pulldown it would be at ground.) | | Basically we see pulses or IR signal. the yellow 'blocks' are when the IR LED is transmitting and when there is only a line, the IR LED is off. (Note that the voltage being at 3VDC is just because of the way I hooked up the sensor, if I had swapped the pullup for a pulldown it would be at ground.) |
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− | [[Fichier:IR-SIGNAL-2.jpg]] | + | [[Fichier:IR-SIGNAL-2.jpg|400px]] |
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| You see that they're not really 'blocks' but actually very fast pulses! | | You see that they're not really 'blocks' but actually very fast pulses! |
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| If you zoom in all the way… | | If you zoom in all the way… |
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− | [[Fichier:IR-SIGNAL-3.jpg]] | + | [[Fichier:IR-SIGNAL-3.jpg|400px]] |
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| You can measure the frequency of the IR pulses. As you can tell by the cursors and the measurements on the side, the frequency is about 37.04KHz | | You can measure the frequency of the IR pulses. As you can tell by the cursors and the measurements on the side, the frequency is about 37.04KHz |
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| Looking back at the first scope picture | | Looking back at the first scope picture |
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− | [[Fichier:IR-SIGNAL-4.jpg]] | + | [[Fichier:IR-SIGNAL-4.jpg|400px]] |
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| The first pulse is 2.5ms. We can use the cursors to measure the remaining pulses. I'll spare you the 12 images and let you know that the pulses are: | | The first pulse is 2.5ms. We can use the cursors to measure the remaining pulses. I'll spare you the 12 images and let you know that the pulses are: |
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− | {| | + | {| class="wikitable" border="1" |
| | align="center" style="background:#f0f0f0;"|'''PWM ON''' | | | align="center" style="background:#f0f0f0;"|'''PWM ON''' |
| | align="center" style="background:#f0f0f0;"|'''OFF''' | | | align="center" style="background:#f0f0f0;"|'''OFF''' |