Incubation - I'm building an incubator at the moment. Designing a five-star model from scratch. I'm not sure if you've ever thought about it before, but incubation is a relatively exact science. Eggs must be kept at 37.5 oC and 60% humidity. Also eggs should be rotated at least once per day.
 This seems like a major feat - doesn't it. Here is my block diagram for the project.
You can click on the image for a larger version.
Thermostat
Item A is the thermostat. I have selected a kit from Canakit that uses the LM314 temperature probe. Here is a picture of the kit once assembled.
 Motor
Next component is the motor driver that turns the eggs. This was fun to design. The trick was to create a module that would turn the eggs slowly through 180 degrees four times per day. There are two modules to this piece. A timer and a motor. The motor is a small DC motor that spins at 10,500 RPM - way too fast to turn eggs! It needed to be slowed right down so that it takes about 20 or 30 seconds to complete half a turn.
 I used two planetery gearbox kits from Tamiya to acheive the necessary reduction in revolutions. The net result is 1:8000 reduction, making my eggs turn through 180 degrees in 23 seconds.
Motor Controller
The motor controller is a device that will turn the motor on four times per day for just 23 seconds at a time. I designed this circuit myself.  Here is a schematic [click for detail]. The timer has four modules in tandem. Left most, based around the 555 timer is an oscilator configured at 1.18 kHz. Then next module containing the 2 x 4040 chips divides this frequency by 16777216 [4096 x 4906] resulting in a signal with a frequency of about 4 hours.
[to be continued]
1:09:01 PM 
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