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Over on the Adafruit forums, robodude66 asked for advise on how to build an egg incubator.
I’m building a chicken egg incubator! Long story short I moved from NYC to Idaho for a gal. Her father is a farmer, and is in need of a large chicken incubator. The size of incubator he’s interested in sell usually for $900 to $2,000 new and are way out of his budget. Seeing as I love electronics, I offered to help build one. Because minds work better in groups, I’m looking for some feedback on my ideas/design.
The main requirements for the incubator are as follows:
- Keep temperature between 99.5 to 100.0f (99.9f is best).
- Temperature fluctuation of +/- 0.5f is tolerable over short periods of time, however fluctuation of +/- 1.0f over long periods of time can be fatal.
- Humidity should be kept at 58 – 60%. During the last two to three days, while hatching, humidity should be increased to 65%+.
- Eggs must be “turned” roughly +/- 30 degrees five times a day, except for the last two to three days during hatching.
A second Adafruit forum member, jigsawz happened to also be working on a similar project (see the start of his setup above). Follow along, and offer up any advice you might have!
FEED
I have a few suggestions:
1. Use a thermistor for your temperature measuring device. It will give you the largest change/degree. The system will have to be calibrated, but since you are only making one, that should not be a problem.
2. Use a stable reference for both the A/D converter and thermistor excitation.
3. Use a PID control loop for temperature.
4. Use a small fan to stir the air. You may want to use a pwm control for fan speed. Prevents hot and cold spots.
5. Use good quality resistors in temp measuring circuit(low drift).
6. Use solid-state devices for heater control. Relays will wear out quickly.
That is all that I can think of.
Comment by David Bley — June 12, 2012 @ 1:50 pm
hey,
i built a chamber with similar requirements, but for an entirely different purpose. I am a hacker chef, and in the process of proofing bread dough, i have to adjust the temperature and humidity throughout the proof cycle. i actually am using an old refrigerator with a humidifier inside. The DHT11 sensor handles temp/humidity monitoring for VERY cheap. As far as PID control, you can use the PID library that is currently available, but auto tuning becomes a pain.
tweet at me if you need any more info @avidanross
Comment by avidan — June 12, 2012 @ 3:14 pm