Modifications

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:

[[Fichier:IR-SIGNAL-1.jpg]]

[[Fichier:IR-SIGNAL-1.jpg|400px]]

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.)

[[Fichier:IR-SIGNAL-2.jpg]]

[[Fichier:IR-SIGNAL-2.jpg|400px]]

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!

If you zoom in all the way…

If you zoom in all the way…

[[Fichier:IR-SIGNAL-3.jpg]]

[[Fichier:IR-SIGNAL-3.jpg|400px]]

 

 

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

Looking back at the first scope picture

Looking back at the first scope picture

[[Fichier:IR-SIGNAL-4.jpg]]

[[Fichier:IR-SIGNAL-4.jpg|400px]]

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:

{|

{| 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'''