expand on how to use this project...

README.md

@@ -73,7 +73,35 @@ Pins
 
 The [pinout guide for the Node151](http://resource.heltec.cn/download/LoRa_Node_151/LoRa_Node_151_Pinout_Diagram.pdf).
 
-The pins PB5-7,9 are used as active low controls for the relays.
+The default pins PB5-7,9 are used as active low controls for the relays.
+They are mapped to channels 0 through 3 respectively.  The LED on PB8
+is mapped to channel 4.  This is useful for testing if a command works
+or not.
 
 The pin PB15 is used as an analog input for an RNG source.  This pin
 should be grounded.
+
+Deploying
+---------
+
+The noral supply used for irrigation values is 24V AC.  This means
+an additional power supply is needed to convert to the 5V supply that
+is used by the Node151.  Make sure this is well filtered as both the
+relays on the board (talked about below), and the irrigation values
+will cause significant noise.  The first PS I made was a simple DC-DC
+buck converter + a full wave rectifier which, while alone was enough
+to power the uC, was not enough when the relays were actuated, and even
+when a little bit of filtering was added after the rectifier (22uF),
+enough to keep it happy w/ the relays, it was not enough when the
+irrigation valves actuated.
+
+In order to control the values, a relay board, similar to [this
+one](https://www.amazon.com/ELEGOO-Channel-Optocoupler-Arduino-Raspberry/dp/B01HEQF5HU),
+can be used.  The nice thing about this board is that the GPIO pins
+on the Node151 are 3.3V, while the relays need 5V to work.  The jumper
+on the right side, VCC-JD-VCC, can be removed to allow this.  The GND
+on the input/VCC pinout is used for the relay power via JD-VCC, and
+NOT for the VCC->INx pins, despite them being next to each other.  The
+GND and JD-VCC should be connected to the 5V power supply, while VCC
+is connected to VDD on the Node151, and INx pins to the respective
+GPIO pins.