Decided to move Gro Bot diary from my website to the forum in view of the imminent release of the V2 software.
When the first builds began to appear I was unable to get the V1 software running so decide that I would wait for the V2 to be developed but continue, albeit at a slower pace , to construct a, ’ Food Bot’ using the ubiquitous dead fridge. Partly as a nod and a wink to the extremely popular movement of, ’ Up cycling ’ , here in Britain and also as I have previously constructed a 3D printer from up-cycled printer and scanner parts which was exhibited as an 'Art Work ’ a la Marcel Duchamp Readymades.
At the start I came across this, TED talk, by Caleb Harper, http://www.ted.com/talks/caleb_harper_this_computer_will_grow_your_food_in_the_future and was inspired.
Just what was needed, but having checked through the OPENAGriculture site, http://openag.media.mit.edu/ , Forum, Wiki and Blog it was obvious an insulated box was required.
Which mass produced insulated box came to mind ? Yes, A Fridge. Just bought a new one and the old one went so no fridge!! to work on. Tried the local fridge seller but was told I would have to wait until one came in. As luck would have it, driving the country lane route back home, there appeared around a bend, in a passing place, the fridge you see here, so it was rescued to be resurrected as a OpenAGriculture Personal Food Computer.
It’s title, The ‘ WILDCARD ‘ Gro-Bot Organeec. is for when it is Exhibited as an Art Work.
!!! Safety alert !!! If you decide to use a fridge.
Older fridges using environmentally harmful refrigerant gases need to be de-commissioned by a registered fitter. In the UK it is illegal to vent harmful gases to atmosphere. Check your local laws for information regarding the scrapping of fridges.
This fridge is labeled as using R600a refrigerant which is, isobutane, an inflammable gas, lighter fuel. It is not harmful to the atmosphere but will ignite easily. At first I thought of keeping the cooling system in case the nutrient solution needed cooling but, as this was an unknown fridge I didn’t want to run the risk of a leak which may cause a fire so removed the cooling system.
Cleaned and painted ready for internal re-fit.
Good clean with bleach, then coated in white anti-rust paint = good as new ! ( except for the lack of cooling power. )
The freezer compartment door is air tight so the idea at the moment is to put the electronics inside and create cable access either through the door or through the back. This will be possible as the cooling pipes run around the top and sides. It might also be possible to have the vent fan at the back and connected by a flexible pipe to a hole in the door.
Keep finding out snippets of info from the OPEN AG Forum, turns out plants like water temperature around 10 degrees cooler than the air temperature.Blue sky thought ! Maybe it’s possible to cool the nutrient water in the fridge freezer and collect the heat of extraction from the fridge radiator. Then feed it back into the fridge to heat the air ? If the freezer section was open to atmosphere it would have a heat source so only the section cooling the water would need sealing from the atmosphere.
Inside I have removed the temperature adjustment sensor from the actuator so as not to compromise the, what I assume is part of, the sealed system.That leaves a useful space which housed the lamp, ( It could be used to mount the camera, and other sensors ), a switch actuated by the door, and access to the outside for cabling. There is also the drain hole which can be used for access. The original container for the lower part of the fridge was missing so this is one that I kept from the fridge that was taken. It is smaller than the original so if I find a larger one then I will use that.
In hindsight it would probably be better to use a freezer rather than a fridge freezer as this would give a bigger grow volume height and therefore a bigger range of plants that could be grown. I am already thinking about converting the most popular greenhouse sizes into grow bots, mostly 6’ X 6’ , 6’ X 8’ and 6’ X 10’, with removable insulation that is only added during the colder months so that running costs are kept to a minimum.
Anyone calculated the average grow volume for the most popular plants ??? Guess current greenhouse sizes are already sized around that.
Sensors and Actuators.
In order to control how a closed system works you need to sense chosen changes in the system and modify those changes to your requirements. Sensors and actuators provide that control coupled with computer applications connecting the two together according to predetermined rules. Here are some of the practical goodies, Temperature / Humidity sensor, light sensor, Ph sensor, Base shield, for the attachment of actuators to the microprocessor control, grove connectors and a small prototyping board. until the system is working I’m holding fire on getting the Co2 sensor as it’s quite expensive. Could be that the v2 version of the Gro-bot has a superior sensor ???
Proposed power supply. If not beefy enough will add another !!