Obviously the first thing which i needed to solve was: how do i power the raspi – the greenhouse has no access to general power (110V / 220V) – yet …

And the second thing : of course the Raspi and the Greenhouse should go online – i’d need network connection to be able to check the status and to potentially remote control some functions (in the faaar future – yet i still did not think on how and what )

First things first – so back to the power problem: The easist thing would have been to attach it to general power – but that would have meant a loooot of digging (at least of few meters of cable in the ground)- also i’m not an electrician and i would have to deal with 220V, additional fuses,etc… That sounded not very much like a hobbiist project and also not what i was aiming for…

Another solution had to be found and i started to dig for alternative power sources – obviously the first thing is solar power – mainly electricity would be needed during the day (when there is hopefully enough sunlight available) to run fans, but of course the Raspi should run 24h a day. So clearly i’d need a battery powerful enough to let the whole system survive at least one night and get recharged with the daylight of the next day.

So i started to look around at my favourite shopping site – Amazon – what is available, if it is in my hobbiiest bugdet and what i’d need on top. After a lot of surfing on the web and digging out my knowledge from my (very basic) electrical engineering lectures i came out with the following shopping list (see components).

The overall invest was also still acceptable: 39.- Eur for the panel, 15.- Eur for the charger, 19.- Eur for the power pack and 10.- Eur for the 12V to USB converter (to drive the Raspi) made a total of round about 84.- Eur

So this would give me a solar panel (20W max power), a charging device (able to handle up to 72W charging power), a 12V power pack with 7AH (so fully charged it should store 72WH – if we run 12h on battery it could deliver 6w constantly). This should do for the beginning.

To set this up i’d need to decide where to put the panel, how to get all devices connected and where in the greenhouse to put the electrical stuff (high humidity is a regular situation in a greenhouse)…