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A little simpler

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I've built a couple tables like this and they work great. Mine sit on sawhorses so they can be taken down for storage off-season. I put the styrofoam on top and pinned the heating cable to it with little staples, and used a couple buckets of pea gravel instead of sand. And I guess I'm old-school but I used a thermostatic controller from Grainger to control the temp. Does it really take a microprocessor?

jennajane's picture

Yup, all the rest of our greenhouse tables sit on saw horses too. I had a spot for this one to be a bit more permanent, and with 300lbs of sand in it, I didn't want to take it down. the pea gravel probably works too, for me I was trying to create a large thermal mass to avoid temperature fluctuations. To add a circuit like this to my microprocessor costs me the price of a relay and temperature probe $25 for the fancy ones, and then I can log the temperature in the table, know how long the heating coil is on under different temperature settings, and patch it into the alarm in case the temps get too high or too low. Plus I am a bit of an Arduino geek.

Post up a picture or two to help out others that are thinking about doing the same thing.