TheNerdyFarmer - 24-4-2017 at 17:15
Okay so I'm not sure if this is under the right topic so sorry moderators. Anyway, I was attempting to design a lab culture incubator for cheap or
relatively cheap. Something like the hundred dollar range.
I would like one that is able to control temperature and humidity with relative accuracy and have a grow light in the top (for algae and stuff
like that). Unfortunately I don't have any decent 3-D modeling software so I can't show you the exact design.
To start off, I searched online to get an idea of what it would cost and found an affordable thermostat, humidistat, humidifier, dehumidifier,
and a peltier cooling unit.(Going to make my own heating unit from metal housing, nichrome wire coils, and a pc fan.) I would like to keep the whole
thing sealed to avoid contamination.
The only thing is that when all working together it would take quite a lot of power to run it. Normally I would be fine with this, but since
incubators usually run for long periods of time, I fear it may trip the breaker in my lab and be a potential fire hazard. I was wondering if anyone
had a better design that they have seen or implemented themselves. I understand that I could just buy a lab incubator, but a reasonably nice one is
like 200 US dollars and I believe I could make a reasonably high quality one for half the money.
I am decent at wiring and okay at reading a circuit diagram so if any of you have any designs that are more cost effective and/or more power
efficient please do share. Thanks for reading thus far and I look forward to seeing some suggestions. 
Metacelsus - 24-4-2017 at 19:21
$200 is actually pretty cheap for an incubator. Depending on how much monetary value you place on the time it would take you to build your own, it
might not be worth it to do so. Of course, you might also value the learning experience of building it.
You might not need the Peltier cooling unit, since when the heat is off the incubator will tend to cool to room temperature, which I assume is below
the desired temperature range of the incubator. A fan might be enough for cooling. Of course, this also assumes that whatever is in the incubator
doesn't generate enough heat to need cooling. By the way, how big are you planning to make this?
phlogiston - 25-4-2017 at 01:11
If you insulate the unit well enough, it does not require a lot of energy.
Perhaps you can start with a discarded fridge or oven. Especially the last option seems attractive to me, as it already has insulation, heater (and
seals?). You would only need to build a new controller for the heater so you can grow (not cook) your yeast/algea.
[Edited on 25-4-2017 by phlogiston]
yobbo II - 25-4-2017 at 05:15
Some egg incubators are just a polystyrene box.. Get some sheets of the stuff and glue together using a solvent.
http://www.ebay.co.uk/itm/egg-incubator-/262949862921?hash=i...
Heater control can be a cheap PID and some nichrome
The actual humidity reading is easy.
http://www.ebay.co.uk/itm/Digital-Incubator-Humidity-Meter-F...
And control
http://www.ebay.co.uk/itm/AC-220V-Digital-Air-Humidity-Contr...
inconjunction with one of these things
http://www.ebay.co.uk/itm/Car-Air-Diffuser-Humidifier-Essent...
Purchase a cheap used egg incubator?
Yob
[Edited on 25-4-2017 by yobbo II]
TheNerdyFarmer - 25-4-2017 at 06:31
Hello. I would like to build one for if nothing else to learn more about how the parts in it work. Plus I think that I could make it for somewhat
cheaper than commercial ones. As for the peltier cooling unit, I would like to buy one first, because it is cheap ($14.95) and second, because it is
about to be summertime and the temperature can reach up to 102 degrees Fahrenheit. I did not want to use a fan in order to keep the inside as sterile
as possible. Unless there is a way to filter the air coming in. (My lab is in an insulated shed and I don't have a window unit to keep it cool.) As
for dimensions, nothing is in stone yet, I would like to have something like 24"x18"x16". But right now I am more worried about the overall
functionality of the mechanism. I planed on using ply board as the outer shell, I have some 1/2" foam board that I planned on using as the insulation.
Then I was going to paint the foam board and then lay some thin scrap plexiglass over it to create a hard surface and to protect the paint. If I am
being over the top on keeping it sterile please do tell, I just thought it was important.
phlogiston - 25-4-2017 at 16:28
I know little about algae, but the Petri dishes commonly used to culture bacteria culture on agar media are not easily contaminated with other
bacteria unless there is a strong air current. I've kept (antibiotic-free) agar plates in plain air for a couple of days without contamination, and
stored them in a fridge for weeks.
Presumably, the seal provided by the weight of a stack of Petri dishes is good enough to prevent environmental bacteria from entering the dishes.
Do you really need the ability to cool your plates?. Metacelsus has good point, you could save a lot of money by not implementing a
feature that you don't need.
TheNerdyFarmer - 26-4-2017 at 05:21
Okay, maybe I will instead of the peltier cooling unit, I will use a pc fan like you all said. Would it be good use an air filter over the fan to
prevent things like dust and stuff from entering?
charley1957 - 7-5-2017 at 17:03
I did this with a dorm sized refrigerator. I just used a clear light bulb rigged up with a water heater thermostat, and installed a PC fan for even
heating in the cavity. Works like a charm for about $11 in parts. Had the fan and the old fridge. Give it a try!
charley1957 - 7-5-2017 at 17:06
I did this with a dorm sized refrigerator. I just used a clear light bulb rigged up with a water heater thermostat, and installed a PC fan for even
heating in the cavity. Works like a charm for about $11 in parts. Had the fan and the old fridge. Give it a try!
TheNerdyFarmer - 7-5-2017 at 17:07
OK thanks!