Once again its the time of year when I plant seeds for my allotment. I already have a heated propagator, but this delivers direct heat, through the soil, without any temperature control. Would like to improve the setup by introducing temperature control of the propagator environment. Any ideas on the best way of approaching this problem.
If you ask like that, with out min and max spec, people would say "Use a microcontroller", or "With PIC bla bla bla, you can easily do..." or stuff like that.
I say, use a thermostat. determine the temp you need and set the thermostat accordingly.
To be more specific. Most seeds can be germinated in the 15 to 25 deg C range. What I want to achieve is the ability to set this temperature in 1 deg increments anywhere within that range. I suppose it would be possible to place a sensor in the propagator to measure air temperature. But this is not the temperature that the seeds are experiencing within the soil. What i require is a temperature sensor that will measure the temperature of the top 5mm of soil (taking into account that the soil is quite often damp) and display this temperature on an lcd display.
Just insulate propagator with styrofoam, best if you have styrofoam box that was used for some packing. Buy room control thermostat that covers that range and stick sensor into the soil. If you want to build one, plenty of schematics on the net, but if you need it fast... Connect heater through thermostat.