Hey everyone! I'm working on an Arduino Uno project that I'm calling a Darkness Detector. The idea is to use a solar cell to power the Arduino and also measure sunlight irradiance over time in garden areas. I want to build it inside a Ball canning jar to keep it safe from weather elements, with a circular solar cell mounted on the lid. However, I ran into a bit of a snag with the calculations I found on pvwatts.nrel.gov that suggest about 6.02 kWh/m²/day in May and 3.21 in January. This translates to approximately 14.6 Wh for a regular lid and 20.4 Wh for a wide-mouth lid. I'm hoping to store any excess power in a rechargeable battery for continuous operation day and night all year round. My plan is to use low-power Bluetooth for data retrieval. I would love to hear any suggestions or insights you might have!
3 Answers
You might want to check out some inexpensive solar-powered garden lights. They usually just rely on a NiMH battery and don’t require too much additional circuitry beyond a simple low voltage cutoff. Since the NiMH battery matches the output of the solar cell, you can simplify your design significantly.
You should consider reducing power consumption. Instead of continuous data sampling, you could log data every minute or even every 5 minutes and put the device in a low power state in between to conserve energy.
Just a heads up, regular solar cells aren’t the best for measuring irradiance accurately. Factors like the angle of sunlight and temperature impact the readings, and you'll likely need to calibrate them annually. If you’re looking to measure irradiance precisely, buying a dedicated sensor might be a better route. On the flip side, if you're just using the solar cell to gauge conditions for battery charging, placing it alongside your main setup could definitely work well.
That’s a good point! But remember, their main purpose is to turn on a light rather than log data, so it might be slightly different from your goals.