Added data handling by LED strips

content/examples/jbang/pixelblaze_output_expander.md

@@ -25,12 +25,47 @@ You can buy this component here:
   * UK: [DialSLV](https://dialslv.com/product/expander/)
   * [Mouser](https://www.mouser.be/ProductDetail/Hencke-Technologies/EM-O3?qs=QNEnbhJQKvY7RFy9Q0t0MA%3D%3D) but doesn't ship to consumers in the EU/UK because it isn’t CE-certified.
 
-The LED strips contain LEDs of the WS2812B type, which means they have SMD 5050-LEDs with an integrated IC-driver, so they can be addressed separately. A few examples:
+## LED Strips
+
+### LED Strips Used in the Examples
+
+The LED strips used in these examples, contain LEDs of the WS2812B type, which means they have SMD 5050-LEDs with an integrated IC-driver, so they can be addressed separately. A few examples:
 
 * [LED strip on Amazon](https://www.amazon.nl/dp/B08Y8QXTCL)
 * [LED matrix on Amazon](https://www.amazon.nl/dp/B0B81R484Z)
 * [Many variants on ebay](https://www.ebay.de/b/WS2812B-LEDs/bn_7005777392)
 
+### How Data is Handled by LED Strips
+
+To control such a LED strip, you need to send it a byte array with RGB (red/green/blue) values. Let's use an example for a strip with three LEDs, on which you want to show:
+
+1. Full red (#FF0000)
+2. Not full white (#A6A6A6)
+3. Full blue (#0000FF)
+
+This means, we need a byte array with 9 values:
+
+| Array index |     0 |   1 |     2 |     3 |    4 |     5 |     6 |    7 |    8 |
+| :--         |------:|----:|------:|------:|-----:|------:|------:|-----:|-----:| 
+| LED         |     1 |     |       |     2 |      |       |     3 |      |      |
+| R, G, B     | #FF   | #00 | #00   | #A6   | #A6  | #A6   | #00   | #00  | #FF  |
+
+The IC of the first led will take the first 3 values from the byte array and output the remaining part to the second LED:
+
+| Array index |     0 |    1 |     2 |     3 |    4 |   5 |
+| :--         |------:|-----:|------:|------:|-----:|----:|
+| LED         |     2 |      |       |     3 |      |     |
+| R, G, B     | #A6   |  #A6 | #A6   | #00   | #00  | #FF |
+
+Again, the second LED will take the first 3 values and output the remaining part:
+
+| Array index |     0 |    1 |   2 |
+| :--         |------:|-----:|----:|
+| LED         |     3 |      |     |
+| R, G, B     | #00   | #00  | #FF |
+
+For this system to work correctly, a strict timing of the data signal is needed. Otherwise the IC will handle parts of the data as being a new package, and you'll get unexpected results.
+
 ## Wiring
 
 To control the PBOE, we actually only need one wire to be connected to the Raspberry Pi (RPi) for the serial data to be sent from RPi to PBOE. But we must not forget one important fact: a LED strip with a lot of LEDs will require more power than the RPi can supply. So we need an external power supply that is dimensioned correctly to provide all the power needed for the strip when all LEDs are at maximum level. As a guideline, 0,1W ~ 0,3W/LED is required per LED. For a strip with 60 LEDs/meter, that means 18W/meter, or a total of 90W for a 5-meter strip. That's almost 20A at 5V!