diff --git a/README.md b/README.md index dd05e38..7705eea 100644 --- a/README.md +++ b/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.