This week I’ve been babying my tomato seedlings and working on the rest of the greenhouse. The tomatoes have sprouted and once they get their first true leaf I’ll put them onto the tray with load cells.
This gives me a bit of time to rework the trays. The idea of using a low pressure bag to lift the trays sounded good… but I was not able to make a reliable bag. The version I have now uses a hot water bottle, which does work, but I’ve already burst one hot water bottle from over pressure. The proper solution I think is a real pneumatic cylinder and solenoid valve for switching it. I tested this version this week and it seems much better. I was going to have it ready to install today but my soldering iron broke. It’s fixable but I need a soldering iron to fix it… The end result is I have to wait until monday to get a new one and test out the load cells in my new pneumatic cylinder tray.
I also worked on the vents. For the time being, I’m just opening and closing the vents manually, I have some insulated panels that I stick in the holes. This is not very air tight, but it doesn’t need to be for this time of year. I made a prototype eversion rig that can deploy and retract an inflated tube through a channel. The idea is that this seals the holes in the channel via air pressure, closing the vent.
There is a ribbon or rope on a reel in the centre that allow the tube to be retracted. My current thought is that this rope could be a bundle of aluminumized mylar tubes. Once it’s been pulled into place but the air pressure of the eversion tube, it can be inflated with CO2 or argon for insulation. I tried making a prototype aluminumized mylar tube but it was very difficult to seal. I need to make something like a seam sealer so I can weld the mylar together.
Sun Aquasystems 