This weather station was part of the Rezodo project. It has been moved to its own project as the Rezodo project was becoming too big to be easily readable !

This weather station is intended to be easily "tunable" to your own needs :

transmission to the base can be done
- directly by the station itself if Wifi is available
- via Lora point to point to get a much greater range (currently working with more than 2.5 km between base and station)
sensors can be choosen among the list and two major versions do exist
- wind only (+ sensors)
- wind + rain (+sensors)

The design of the two main versions is basically the same but the "mechanical" parts, of course, differ. We will cover the two versions.

"Wind only" weather station

As I do belong to a RC flying club, we need to know the wind conditions at the airfield. These conditions are locally changing quite fast and weather forecast is not accurate enough for our hobby !

So I decided to design a "Wind only" version of the weather station.

Here it is, installed at our airfield

The airfield is far away from electricity network and at 2.5km from the first building where we have installed the Lora receiver.

Everything is working now and we have a public access to these nice gauges!

Building this station is not complex. Read all this description and the logs and you will be able to build yours !

As you can see the wind sensors do work in very low wind conditions.

Price for this "Wind Only" weather Station including both emitter and receiver boards (GTW0 + GTW1) is less than 50€. Bill of Material is accessible here

Full weather station

This one is the most complete version, including all the sensors. It mainly differs from the previous one by the addition of a rain gauge.

The electronics goes inside the bottom box, wires go to the sensors into the pipes. PCB is protected against rain.

Here is a picture showing "exploded" view of the weather station:

And here it is during tests:

Weather station electronics

This schematics summarizes the electronics embedded into the weather station. The same PCB is used for the various versions of the weather station, and even for the Lora gateway 0 (the one simply equiped with Lora + wifi access + mains power supply).

In a few words, it has the following components:

a lora module for long range communication between Gateway 0 and Gateway 1
an ESP32 MCU + ESPNow (to be connected to Rezodo FDRS network if needed)
a rain gauge equiped with weighing sensor for accurate measurement
a wind direction sensor with a Hall encoder delivering 4096 angular postions (contactless... no wear)
a wind anemometer with hall effect sensor (contactless... no wear)
temperature, humidity, pressure, light sensors

More details into this log please read it as it contains important informations.

Components + mechanical parts for this schematics should cost around 65€. This price is for the "full" Lora weather station and does include the Lora GTW0 and GTW1...

To build the weather station you will have to add a few 3d printed mechanical components.

All the 3d printed parts are available on thingiverse (links on the left of the main page of this project).

I printed them with plastic bottle PET filament. See here : Pullstruder project on hackaday.

Never print these parts with PLA... They will melt under the sun. Choose PETG or ABS or PET.

PCB

The PCB have been sponsored by PCBWay. You can order them here : Weather Station PCB @PCBWay

As you can see, this is the V2 version of this board (the latest one).

More details into this log

The rain gauge

There are a few ways to measure rain. The most commun design is "tipping bucket"

These rain gauges if not "dynamically corrected" may suffer from poor performances. They under estimate high rains and have a poor precision for "small rains". The bucket has to "tip" before counting the water inside...

Please...

adding Wind Gusts to the weather station
JP Gleyzes • 2 days ago • 0 comments

A lot of our RC pilots were more interrested in "strong wind" rather than "averaged wind speed".

So they asked for Wind Gusts values.

I made it !

Gusts are measured every 5s during 30s while I also measure average wind speed.

Latest commit on my Github page contains all the source code.

While the thingspeak channel of our Airfield weather station can now proudly show "Gusts"
configuring GTW0
JP Gleyzes • 09/09/2023 at 09:47 • 0 comments
Your GTW0 is the one which is connected to internet and which synchronizes the weather station (and other GTWs if a wider Rezodo network is in use).
To configure the GTW0 we have to set up the Wifi credentials and the frequency of sensors measurements.
This is done by touching the TP1 pad on the PCB and (while touching the pad) resetting the ESP32
Then a web access point will pop up on which you can connect your smartphone
Connect to this hotspot then enter
1. a valid wifi ssid and password
2. the frequency to wakeup your weather station in minutes
that's it !
Wind Direction and weighing gauge calibration
JP Gleyzes • 08/18/2023 at 12:27 • 0 comments
Wind direction sensor

Calibration the wind direction sensor simply consists in telling him where is the north !

Indeed the magnet can be glued in any position on the shaft so the north pole is totally into a random position!

To calibrate the "north" we simply align the sensor to the "north" direction, then we press the touch3 pad on the ESP32 and reset the ESP32 (remove your finger from the touchpad after releasing the reset button).

This touch pad( named TP1) is also in the bottom right corner of the PCB

Calibration is done by software and value is stored into the ESP32 flash memory.

It's straightforward and simple!
```
 float angleValue = as5600.rawAngle() * AS5600_RAW_TO_DEGREES;
  if (touch3detected) //calibrate sensors
  {
    Serial.println ("calibrate anemometer");
    calibAngle = angleValue;
    preferences.putFloat("calibAngle", calibAngle);
  }
```
You don't even have to physically point the sensor to the north. Just align the sensor with the axis of the PVC pipe (opposite direction of the solar panel).

But you will have to align the solar panel to the south direction when fixing the weather station on the roof.

So, wind direction sensor should be calibrated in this position:

weighing gauge calibration

Calibration of a load cell is quite easy:
- determine the zero offset "tare"
- substract the zero offset from the raw value and then linerly convert this value to weight
In my Weather station the zero offset is dynamically determined. The logic is simple :
- once a day empty the bucket --> get the zero offset
- if weight decreases, abnormal condition then empty the bucket --> get the zero offset
- if weight is too big then empty the bucket --> get the zero offset
The scle factor needs however a static calibration. It is done by weighing a know weight after having reseted the ESP32 while pressing the TP1 touch pad
```
 GetRawWeight();       //HX711 will sleep after weight acquisition
  if (touch3detected)
  {
    Serial.print ("calibration HX711... ");
    calib = CurrentRawWeight;
    Serial.println(CurrentRawWeight);
    preferences.putLong("calib", calib);
    emptyBucket();
  }
```
The "calib" parameter is stored into the ESP32 flash. This parameter coresponds to the raw value of a know weight which is "calibWeight". Note that this value is in tenth of grams. I do use a steel ball the weight of which being 33.5g...

Change this value to the weight of your calibration steel ball !
```
//scale
#define PIN_CLOCK  32        //output to generate clock on Hx711
#define PIN_DOUT   34        //input Dout from Hx711

long calibZero = 0;  //No load sensor Output
long calib = 130968;          //sensor output - calibZero for Weight calibration --> will be auto calibrated later
int calibWeight = 335;         //weight at which calibration is done --> expressed in gramsx10. eg 335 means 33.5g
```
So the procedure to calibrate the load cell is :
- insert your steel ball into the bucket
- press the TP1 touchpad and hold your finger on it
- reset the ESP32
- release your finger
That's it

You should note that the same touchpad is used to calibrate both the load cell and the wind direction sensor.

Be sure you are into the calibration conditions of these two sensors while calibrating
experience feedback (REX) on power management
JP Gleyzes • 08/17/2023 at 14:12 • 0 comments
A critical part of my project was power management.
Here are a few words of "REX" regarding these aspects.
The wind only weather station has now been operated on a daily basis (24/24) for more than 2 months and has performed sensor acquisition and transfer of data over Lora (2.5km range) every two minutes during day and once every 1 hour during night.
All this being operated on a single 18650 Li-ion battery charged with a small 2W 6V solar panel.
Here is the graph of the panel voltage captured during a few days :
We can clearly see the repeating pattern where the panel outputs 0V during night and boosts up to 7V during full sun.
If we zoom here is the detail:
1. during night I automatically perform data sampling once every 1 hour to save power, at sunrize voltage is slowly climbing while at sun set it slowly decreases
2. during a few hours the solar charger is lacking efficiciency (it's a linear charger...) and the panel falls down to 5V but charges the battery until full charge where the panel recovers and outputs full power (7V)
3. but even during full charge when a cloud hides the sun, voltage may drop a little...
In conclusion, the system seems to be very well "balanced" with good margin to allow operation even during winter time...
In case of (unexpected) battery depletion I could easily change the sampling rate to 4 min instead of 2 min during winter season! But we will see this after a few months !
Currently the fast 2min acquisition is not a concern, even during very cloudy days the battery was charged enough to power the weather station.
gauges on ThingSpeak using Matlab
JP Gleyzes • 07/18/2023 at 19:13 • 0 comments
DIsplaying wind direction needs particular "compass gauges".

Here is how they look on my "wind Only" Weather Station

Among these gauges only the second one (wind Speed) is native, the first and third one need a few lines of matlab code.

Let's start by creating a "Matlab Visualization" on your channel:

Click on "new visualization" then select the compass one:

Click on "create" and you will get sample code for this visualization:

You can save and run this code to get this result:

Although it's a good starting point, it's far from being perfect to display wind direction:
- North south Est West are not displayed
- arrow lines are pointing to the the direction from where the wind is coming
- 0 is on the right side instead of pointing to north
- angles are counter clockwise instead of classical ClockWise
I managed to find Matlab Gurus to help me correct these defects.

The source code is self explainatory and can be found on my github page: https://github.com/f2knpw/Long_Range_Weather_Station/tree/master/Matlab

If you change the code by this one you will get the expected result:

You can of course save this gauge on your channel:

When reading the source code, you will discover that it is more a less a "hack"... There is no proper way to achieve this result... that's a pity !
Adding a biquad antenna to increase Lora range
JP Gleyzes • 07/18/2023 at 12:01 • 0 comments

To increase range of my Lora network I decided to try a biquad antenna.

My lora frequency being 868 MHz I used this online calculator to get the proper design: https://www.changpuak.ch/electronics/bi_quad_antenna_designer.php

Then I built a jig tp help bending the 2mm copper wire. You can find it on Thingiverse : biquad antenna

This being done we attached the antenna on the roof.

Results were impressively good. Eventhough I didn't make a metal reflector for this antenna, I got a lot more power from my "Wind Only" Weather Station located 2.5 km away from the roof.

The BiQuad antenna is a simple antenna design that offers many advantages. First is the simplicity of the design.

The radiating element are two square with the side length equal to 1/4 midband wavelength, 83.8 mm for

868 MHz in our case.

Polarization of the antenna is 90 degrees from the position of orientation of the biquad, i.e. horizontal biquad (as shown on the roof) has vertical polarization.

The metallic reflector reflects the electromagnetic waves back to the front of the antenna (-Z-axis), hence reducing the radiation to the back and improving the antenna gain and directivity in the forward direction. The obtained gain measures the ability of the antenna to concentrate radio frequency energy in a particular direction. It is typically measured in dB and found equal to 10.5 dB for the studied antenna design.

Note that the "z axis" is perpendicular to the biquad

Without the metal reflector my antenna behaves more or less like a dipole antenna but with better gain and directionnality.

Configuring your Weather Station

JP Gleyzes • 07/17/2023 at 15:22 • 2 comments

Sensors selection

Depending on the sensors you have soldered to your board you will have to comment/uncomment a few lines of code... Open the GTW1 .ino file

Full Weather Station

Here is the sensors selection for my "full weather Station"

//sensors selection
#define HAS_HX711       //uncomment for weighing rain gauge
#define HAS_ANEMOMETER  //uncomment for anemometer
#define HAS_AS5600      //uncomment for Wind Direction sensor
#define HAS_BME280      //uncomment for temperature + pressure + humidity BME280 sensor
#define HAS_DS18B20   //uncomment for DS18B20 temperature sensor
//#define HAS_DHT22     //uncomment for DTH22 temperature + humidity sensor
//#define ENABLE_WIFI   //uncomment to enable wifi debugging (avoid this when ESPNow in use)

As you can see everything is selected but the DHT22 which is useless when you have a more precise BME280 !