i wanna build a dehydrator out of a old refrigerator. i know arduino will be the best controller.
i plan to use a heat gun for a heat source, the evap fan for circulation. i intend to control temp and humidity. i want to incorporate a alarm circuit for heat failure, fan failure, and out of range for temp and humidity. and i'll also need a timer
maybe bluetooth for parameter monitoring.
so there i am folks. any ideas or thoughts are appreciated
I don't know how a dehydrator works.
What is your Arduino programming experience?
If you are new to Arduinos study several of the example programs that come with the Arduino IDE. They will probably cover all the techniques you will need.
Then build short programs to learn how do do all the individual parts of the project, one at a time. For example measure temperature and humidity, check for heat failure, for fan failure etc. Only start creating the composite program when you can do all the parts individually. Successful programs are always a collection of small parts.
Planning and Implementing a Program
A dehydrator uses the condenser coils themselves as the heat source - a heat gun is gross overkill.
dehydrator, heat up to about 150 degrees F for a high temp ?
the heat gun will be higher than you need. a simple hair dryer on low would be fine.
Heat is one side, but air flow is the other. you need to cut holes in the thing.
I think lots of research into air flow and heat.
IMHO it would be best to have low intake and low exhaust, with the exhaust from a fan.
the fan would pull air from the top of the inside.
not just an open top as all the heat would be lost rapidly and the layers of stuff would be on temperature stratified layer,
ESP8266 can use a BME280 for temperature and humidity
need one on the inside and on the outside
you can run multiple fans and use a relay to turn on the heater
I would suggest that you add a display to show humidity and temperature. the 0.9 OLED makes that simple as it it two wire as is the BME280. all sorts of help on those.
For the software and sensor side, this is all beginner stuff.
the ESP8266 can offer a link for your phone.
lots of help here : [beginners guide to ESP8266](https://tttapa.github.io/ESP8266/Chap01 - ESP8266.html)
search term: refrigerator dehydrator conversion
one guy used lightbulbs. another used the bottom of a crock pot he found at the dump.
Have you considered looking around at the board manufacturers? I got, at a low price, a burn-in oven for circuit boards. The internal racks are highly configurable, temperature is adjustable and measured and regulated in several locations, and air flow is adjustable and monitored in several places.
A dehydrator for what usage?
For high volumes at atmospheric pressure or for compressed air?
That will lead the design...