Davis weather station set up

To set up a weather station, you should prepare:

1. One Davis rain gauge;
2. One Davis wind anemometer & vane;
3. One radiation shield (one SHT31 humidity sensor inside);
4. One UV sensor;
5. One enclosure box;
6. One solar panel assembled with steel angle, a lead acid battery and a solar regulator;
7. One tripod to support all the sensors, solar panel and enclosue;
8. One datalogger;
9. One WLAN adapter and antenna.

The main components of the weather station are shown as follows:

Sensors' wiring

Sensors' wiring sketch

Note: For Davis anemometer, it is necessary to connect a pull-up resistor (4k7 Ohm or larger) to Analog pin in datalogger.

Sensors' connection to datalogger V3

Davis vane - wind direction measurement diagram

The wind vane has a 20k linear potentiometer attached to it. The output from the wind direction circuit is connected to a analog pin on the Arduino. As we move the wind vane around we should get a reading between 0 and 1023. The Arduino has a 10 bit A to D converter which gives us the range of 0 to 1023. This would also correspond to a voltage of 0 to 5V. In the software we need to convert the 0 to 1023 to a 0 to 360 range to give us the wind direction.

How to hoopup Davis anemometer to Arduino: http://cactus.io/hookups/weather/anemometer/davis/hookup-arduino-to-davis-anemometer

The completed weather station set up on the roof

Please note: it is quite important to put weight on the tripod feet or fix with mouniting wires to protect the weather station from being blew down by strong wind.

Maintenance

25/03/2021 It was found that the enclosure of the weather station on the roof was not sealed well as a small amount of water ponding underneath the battery and the desiccants were soaked. So, silicones were applied to the top of the enclosure.

Below are obsolete contents

1. trying the compatibility between sparkfun photon board with Davis TO180924

   a. rain gauge is found compatible. detail calibration is required as the surface area and the size of the tipping bucket is different. pins are found at the middle of the RJ21 pins.

2. windows 10 is chopping

   b for spark fun weather station. the innter two pins (in the middle) is for wind speed (yellow and red in the last terminal to logger), the greater the wind is, the higher the resistance is. the outer two pins are for wind direction. (black and green) see manual for detail c.for Davis, the innter two pins are for wind direction

3. Photon particle + sparkfun photon weather shield when photon weather connected to internet:

   power 5.01v current 0.102A