I have a need for a 'device' that would keep a gla

>>1067092
just put a light bulb near it

>>1067093
Could that be an infrared lighbulb? I don't want a a visible light one.

But I would still prefer the resistor strips (or something more compact and what I can power from USB) more, if it sounds sane and would work.

Are you growing mushrooms? Other than the mostly empty part, it sounds like you're farming mushrooms.

>>1067092
Heat is basically power,
How much heat do you need in Watts.
Then power = current x voltage
But you want resistance and say its usb so its 5v and you know the power so rearrange
Current = power / voltage
Then to get current
Current = voltage / resistance
So put it all together
Resistance = power/ voltage^2
Or something like that,I was never any good at maths

>>1067098
Nah, I'm keeping a pet praying mantis.

>>1067101
Thanks, but this part I actually kind of knew, I need to figure out much Watts do I need to heat the jar from the ~15 to ~20 degrees. It's just slightly bigger sized pickle jar. Or do you think I can just buy pretty much whatever resistors and just play around in arduino till I get it right?

>>1067107
>pet praying mantis
Poor mantis. Build it a nice garden with lots of aphids and shit to eat, instead. Make him a little mantis hermit shack with a tiny rocking chair.

>>1067092
https://www.youtube.com/watch?v=Bw2p-Dmn48U
This may help

>>1067107
Newtons law of cooling. Assume the tempurature of the jar is equal to the temperature of the air inside, and find the rate of cooling of the jar. The rate of loss of thermal energy of the jar at the needed temperature is the amount of power you need to put out with your resistor. Note that the resistor is more likely to conduct heat along the wires than to the air though, so you'll need to solve that somehow.

>>1067107
Or get an arduino and a thermal resistor if you want to be super cool. Just check the thermal resistor every minute or so and use that to adjust the resistor

>>1067130
Mantises are pretty happy in small enclosures that are at least two times as wide and three times as tall. My friend caught her mantis when she was walking to the store. She saw it on some kind of bush on her way to the store. She had nowhere to put her (and didn't want to carry the mantis on her head in the store), so she continued the the store, did her shopping, and when she was coming back quite a while later,
the mantis was still on the same spot. They don't really move unless they are forced to buy weather conditions/birds/hunger.

>>1067460
maybe it was sleeping, like every night you do laying still for 18 hours

>>1067092
>b) use this: http://www.ebay.com/itm/Fast-USB-Tea-Coffee-Warmer-Heater-Cup-Mug-Pad-4-Port-USB-Hub-Office-PC-Laptop-/171778468698 somehow, probably with a gap between the jar and this (I need ~20, not 60)

lol, I just thought that

sit the jar in a dish of water that is on top of the heater

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>>1067460
At least give it a decently sized habitat, maybe a two gallon fish tank.

>>1067746
This. Don't be an asshole op. Just get a little reptile tank and heater for ten bucks.

>>1067092
https://www.youtube.com/watch?v=REIIeXKPk6k

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you dont need no stinkin' arduino. you need a 12V 2A wall wart, a mechanical thermostat, and some 3-4 feet of nichrome wire from a hair drier. that's $1.50 + $2 + $3 at the thrift store.

you can shape, wrap, and cover the wire anyway you like, anywhere you like. by adjusting the length of wire, you adjust total power. longer = higher resistance = lower power. and the thermostat adjusts the on/off cycle to control temp, of course.

I'd just use a PIC micro controller and thermal resistor, and hook it up so that a minimum temperature value activates a mosfet/relay attached to a coil of resistive wire. I did half of this for a digital electronics paper, so I could provide some information if you're interested.

Or just do this:
>>1067887
Probably easier than a microcontroller. But it's never too late to learn BASIC!

>>1067097
U can buy blackout heat bulbs in pet stores. Is a heatlamp but u cant see light. Adjust distance to proper temp.

Profit.

>>1067130
ITT: we help op build a sweet terrarium for his mantis and it gets its own cuckshed made from popsicle sticks.

YAAAAAAAS

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Praying mantises are cool as hell, but they usually die around this time of year. I kept a bunch when I was younger but one time I had one that I noticed acted differently. It didn't move as much and seemed kind of lethargic like it never cared when I touched it. I took it out and held it for a bit and some kind of motherfucker parasitoc worm fucker jumped out the side of its abdomen and onto my floor. It was small and not like those creepy ass horse worm things. It scared and grossed the absolute shit out of me. The worm thing quickly formed some type of cocoon but I never got it to hatch, so I think whatever that abomination was it had died before maturing. Mantis bro died shortly after.