I need to record the wind speed and the solar radiation power (irradiance) in order to evaluate how much power could be extracted with a wind turbine and/or solar panels.
I will measure for one year, analyse the data and then design an off grid system with the good components according to my needs.
This system writes each minute how many turns has done the anemometer and the value returned by the solar radiation sensor on an SD card. It is powered by a small solar cell so it can works as long as there is sun. (The memory card is not a limiting factor as it can hold hundred of years of data). There is a 2500 mAh 3,7V liPo battery so it can works several days without light.
Step 1: Tools and Material
Not so many tools are required. All depend on what you buy and what you make. I decided to buy the electronic on adafruit so no soldering was required. I also had this waterproof enclosure and clamps so no special tools were needed. I just cut the wooden part to hold the electronic inside the box and made a couple of holes in the aluminium plate to secure the solar cell and the anemometer.
I decided to make my own 3d printed anemometer (https://www.instructables.com/id/3d-Printed-Anemometer-Under-5/) but you can make yours with ping pong balls and ice-cream sticks if you don't have a 3d printer.
I had the opportunity to get this super accurate solar radiation sensor(vantage pro 2, davis intruments) but my first idea was to measure with a simple photodiode. I guess that if you are not a metrologist who needs super precise results, a photodiode should be fine. In my case I just want to know how much time the sun was shining and how much time it was cloudy. I will also use these data to count the days because I don't have a real time clock. The micro controller oscillator is not precise so it can not be used as a reference on the long range.
Here is the electronic I bought on adafruit:
- Super Bright White 5mm LED
- Small 6V 1W Solar Panel
- Lithium Ion Polymer Battery - 3.7v 2500mAh
- USB / DC / Solar Lithium Ion/Polymer charger
- 3.5 / 1.3mm or 3.8 / 1.1mm to 5.5 / 2.1mm DC Jack Adapter Cable
- Hall effect sensor - US5881LUA (for the anemometer)
- SD/MicroSD Memory Card (8 GB SDHC)
- Adafruit Feather 32u4 Adalogger
- Feather Header Kit - 12-pin and 16-pin Female Header Set
Step 2: Program Your Controller
Plug the USB and load this code with the arduino IDE. The pin assignment is indicated as commentary in the code.
Each time the south pole of the magnet pass in front of the Hall sensor, it triggers an interrupt which increases a counter.
Each minutes, the counter value is saved on the SD card (as well as the radio sensor) and the counter is reset to zero.
Test if everything is working properly.
Step 3: Packaging
Put your electronic in a waterproof box. I used some hot glue to close the wire holes. With small screws from old toys, I secured the boards on a piece of wood. For the battery I made a frame and lock it with a piece of foam.
To be able to control if the system is alive, an LED is blinking each time the data are saved on the card. On the box I use, there is a small window so I placed carefully the LED in front of it. If you have a transparent box, it will be easier.
That's it! Close the box and install your system near your future off grid tiny house.