4 ‐ Hardware - tk5ep/WX-station-LoRa-WiFi GitHub Wiki
The sensors should now be connected to the board.
COMPONENTS
I've bought most of the material on Aliexpress. I give the item numbers below, the links I would give only work for a specific language.
| Part | Item |
|---|---|
| The LilyGo T3 v1.6.1 board | item 4001178678568.html |
| The RS485 interface | item 1005001621746811.html |
| The windvane and windspeed | item 1005005500304078.html |
| The rain tiping bucket sensor | item 2026877912.html |
| The DC-DC converter | item 32653212622.html |
| The BME280 | item 32862421810.html |
An additional 12V small power supply (like a wall plug) is needed to supply the complete board. (DC-DC converter and RS485 sensors)
WIRING
The wiring diagram for a T3 board is as shown :
RS485 SENSOR SETUP
The RS485 wind sensors are all coming with the same ModBus address 0x01. It is necessary to change at least one of the 2 sensors.
By default the settings.h file sets the default addresses for the windspeed sensor to address 0x01 and the windvane to 0x02.
The sensor address can be changed with the manufacturer software or with the WX station software.
Do the following :
Only the windvane should be connected to the RS485 interface.
On the T3 board, the pin IO25 should be tied to the 3V3 pin.
The green LED should light up. Press the RESET button.
The OLED should confirm that the address has been changed. Remove power on module, the link from pin IO25 to 3V3 and the 12V supply to the sensor.
Reconnect both sensors and restart everything.
The software can change any address to any other address. By default, it changes 0x01 to 0x02.
Changing the following 2 parameters in the settings.h file, will change the any address to any other. ie 0x02 to 0x01.
const uint8_t OldSensorAddress = 0x02;
const uint8_t NewSensorAddress = 0x01;
Remember that all the RS485 ModBus sensors are connected in parallel, this is A+, B-, GND and +12V pins. If the distance between the module and the sensors are over a few meters, a 120 ohms terminator resistance must be soldered on the end of the bus on the sensor side.
CASING
I have wired all the modules on a test board on which I've soldered female pins. The modules have male pins soldered and they can be plugged onto the "main" board.
Unfortunately, the RS485<>TTL board doesn't have a standard pin spacing. Some tweaking is necessary.
The protection box is an IP67 plastic box.
After a previous bad oxydation experience, I've varnished all connections as well as the surface of all modules. Care has to be taken not to put any varnish on the very small sensor on the BEM280 board.
The SHT31 sensor has a Teflon membrane that is normally protecting a bit the sensor, it "might" be better than the BME280 on this point.
The i2C sensor is connected on pins IO21 (SDA) and IO22 (SCL). The VCC line is connected to the 3V3 pin, and GND to GND.
I've put the temperature/humidity/sensor (BME280) in a pill tube in which I've made 2 large cuts to let the air flow through it.
To ensure some protection against insects, dust, etc..., I have rolled a dishwashing scouring pad around the tube.
The whole is housed in a recovered weather shed.
FINAL ASSEMBLY
The sensors and box are fastened to some tubes with collars and small plates.
This should complete the assembly.