doc: active PoE will not be supported

CHANGELOG.md

@@ -0,0 +1,4 @@
+v0
+--
+
+first prototype, with the bare features

README.md

@@ -18,21 +18,44 @@ usage
 limitation
 ==========
 
+logo
+----
+
+You can see the WLED logo on the board, but this is NOT AN OFFICIAL WLED BOARD.
+There is not such thing as a WLED board, as WLED is just a firmware.
+The logo is only there to show the board is intended to be used with WLED.
+And I find the logo nice.
+
+power
+-----
+
 The built-in 5V DC-DC converter is only rated up to 5A, limiting the total maximum output to 25W.
 This means you can power up to 5 m of WS2812b 30 LEDs/m strip at full brightness.
-For more, limit the brightness in WLED, or use multiple boards and chain them.
+For more LEDs, limit the brightness in WLED, or use multiple boards and chain them.
+
+The spring loaded terminals are only rated for 2A, with a maximum wire size of AWG 20.
+If you intend to draw more current, you can add a connection to another 5V output from the LEDs or power port.
+This is particularly relevant for re-injecting power, which you should do minimum every 5 meters.
+If you need even more current, or use thicker cables, just solder the cable directly to the pins on the bottom or on the rear tab of the barrel jack connector.
+If you need more than 5A, you are exceeding the use case of this board.
+Switch back to using a external power supply and connect the LED strips directly to it.
+You can even power the board with the same 5V or 8-36V power supply using the power port.
+
+features
+--------
 
 Features already implemented:
 
 - daisy chain capability (providing data and power)
-- built-in power 5V power supply (input up to 36V, output up to 5A)
+- built-in power 5V DC-DC converter (input up to 36V, output up to 5A)
 - RS-485/DMX512 interface (not isolated)
-- RJ45 port, providing power and data, 2x for chaining capability
+- RJ45 port, providing power (PoE, passive, alternative B) and data (as used in DMX512), 2x for chaining capability
 - RJ45 individual wires connector, using easy to use spring loaded terminal, for allowing using Ethernet cable in waterproof enclosure, where the 8P8C connector does not fit through the PG7 cable gland
 - DC barrel jack power input, for 5V and 8-36V, for convenient use with power bricks, allowing injecting power
 - power wire connectors, as alternative to the barrel jack, for larger power supplies and usage in waterproof enclosure
 
 - proper 5V DOUT for WS2812B IC input, 5 channels (can be combined for LEDs requiring an additional clock signal)
+- in-line LED data resistors for [signal conditioning](https://quinled.info/data-signal-cable-conditioning/). Ideally it should use a smaller value since it's intended for running the signal along ground over short distances, but there were already 100 Ohm on the board for DMX512 termination, and it allows better compatibility for longer single ended cables.
 - external WiFi antenna port, by using the I variant of the ESP32-S2-WROOM, with appropriate connector
 - PCB fitting in [sonoff waterproof enclosure](https://www.sonoffegypt.com/products/sonoff-ip66-waterproof-case)
 
@@ -50,6 +73,7 @@ Features will not be implemented:
 - full isolation: not really needed as the devices should be chained with a single power supply, preventing any ground potential difference. The splitter board will provide isolation, at the beginning of the chain.
 - USB Power Delivery: this is just a convenience feature, but using expensive lower power USB chargers is not ideal for the intended usage (festival installation)
 - Lithium battery input and charger: it does not fit the intended usage, with large external power supplies providing enough power for power hungry LED strips. Small batteries would not be able to handle that over longer time. You can still use the 5V power input though, and charge the battery separately
+- Power over Ethernet (active): I do use passive Power over Ethernet, by providing power on 2 pairs of the Ethernet cable that are not used for 10/100 Mbps communication. This allows using very simple and inexpensive injectors to power power, using and power supply. Active PoE require specials and more expensive injectors or power supplies, and complex extractors in each device. This is a to hard requirement. Feel free to use PoE though. There are plenty of relatively cheap injectors and extractors that you can use as external devices next to the boards.
 
 background
 ==========
@@ -103,10 +127,41 @@ Thus interface with is will be very easy and there is a lot of software support.
 The limitation is that it supports only one universe of 512 channels, or 170 RGB LEDs.
 A solution would be to control modes instead of individual LEDs.
 
+intended use case
+-----------------
+
+The purpose is to provide a simple board able to control LEDs strips.
+It should be better than general purpose development boards.
+A built-in voltage converter allows driving an LED strip.
+It is intended for small installations, not requiring more than 5 meters of LED strings.
+This keeps the power supply small.
+The board is not intended for large LED installation requiring a lot of power.
+
+The board should be cheap enough to be a default choice when creating a small LED installation.
+the goal is at 5 to 10€ per board.
+This prevents me for using Ethernet, since the PHY and magnetics are expensive (~ 3€).
+
+It should not require a complex installation.
+Something like a LAN requiring a permanent switch or router is already too much.
+The board should be able to work on its own.
+
+It should be make it easy to create multi-device installations.
+This is provided by the chaining capability.
+You can connect one device to another, and the job is done.
+This single link provides power.
+This allows using a single power supply for the whole installation, just connected to the first device in the chain.
+It should use cheap and common cable for the chain link, such as Ethernet cables.
+
+It should accept common off the shelves power supplies, such as 12-24V 2-4A bricks.
+
+The chain link should also allow synchronising the devices.
+Ideally it should also provide an interface to reliably remotely control them.
+Thus the DMX512 protocol.
+
 features
 --------
 
-Here a wish list of features I began with, in decreasing order:
+Here a wish list of features I began with, in decreasing order of importance:
 
 - daisy chain capability (providing data and power)
 - built-in power 5V power supply (input up to 30V)
@@ -127,13 +182,15 @@ Here a wish list of features I began with, in decreasing order:
 - high voltage input (up to 60V, using TPS54560DDAR)
 - USB Power Delivery power input (using IP2721 or FUSB302)
 
-I'll probably add them with each new version
+I'll probably add them with each new version.
 
 other
 -----
 
 Here a list of other similar LED controllers:
 
-- [QuinLED-Dig-Quad](https://quinled.info/pre-assembled-quinled-dig-quad/): WLED compatible, but not DMX or power supply
+- [QuinLED-Dig-Quad](https://quinled.info/pre-assembled-quinled-dig-quad/): WLED compatible, but no DMX or built-it power supply for the LEDs
+- [8 Port LED Distro](https://github.com/bobko69/8PortLEDDistro): similar to QuinLED-Dig-Quad, with Ethernet (not just an option), but same issues
+- [QuinLED-Dig-Octa System](https://quinled.info/quinled-dig-octa/): similar to 8 Port LED Distro, just beefier
 - [SP201E](aliexpress.com/item/1005005061637017.html): cheap DMX512 LED strip controller, but no WLED, RJ45, or power supply
 - [H807DMX](https://www.aliexpress.com/item/1005005293168050.html): compatible with most LED strips, and has RJ45 DMX512 input, but no WLED or power supply

library

@@ -1 +1 @@
-Subproject commit 2340ed868eee667502c883a2e436de554ff32a4e
+Subproject commit cad0c1be57cd0fd363213b16c048edd32f382979

version

@@ -1 +1 @@
-0
+1