heating a small chamber

Projects General Guidance
1

I have to heat a small chamber approx. 1ft cubed. anyone have any ideas how i can do this, i've been told use a teg or nichrome wire and a fan. any other ideas? it just needs to get hot enough to dry water from solid products and have a variable time on it

2

Buy a heater? Don't mess around with winding your own nichrome elements. You could probably buy the elements alone or tear apart a toaster.

3

Heat it to what temperature?
.

4

I'm not familiar with teg, but nichrome is a common in heaters. You can also use a [power resistor[/url].*

Heat is directly related to power and you can calculate power as Voltage2 x Resistance. Nichrome wire has an Ohm's-per-foot (or Ohms-per-meter) rating, depending on it's gauge/diameter. If you use a resistor its common practice to "de-rate" the resistor's power rating and only run it at about half it's rated maximum power. (I'm not sure how to find the maximum power/current rating for nichrome wire.)

Of course, your power supply has to supply the power... In case you don't know Ohm's Law, Current (Amps) = Voltage/Resistance.

I have to heat a small chamber approx. 1ft cubed.

There are always some unknown variables (mostly insulation & thermal leakage) so it's hard to predict how much power you need. You might try putting a 100W light bulb inside to see how much temperature-rise you can get, and how long it takes.

5

put in an incandescent light bulb and add a switch.

too hot ? use a smaller bulb.

christmas tree timer.

6

Hair dryer ?

7
8

I'd go with an incandescent light bulb. That is what my lava lamp uses.

9

zoomkat:
I'd go with an incandescent light bulb. That is what my lava lamp uses.

remember the advertisements for the EASY BAKE OVEN ?
40 watt light bulb.

10

dave-in-nj:
remember the advertisements for the EASY BAKE OVEN ?
40 watt light bulb.

40 watt appliance bulbs seem to be the standard heat source. I think the easy bake oven went away when kids started to do DIY baking with things containing eggs and such. When crock pot slow cookers became popular many years back, some "cooked" so slow that they turned into incubators.

11

I remember my sister's Eazy Bake used a 100W bulb... And from what I remember it didn't "bake" very well. (A regular toaster oven is usually 1200W.)

They still make an Easy Bake but it no longer uses a 100W bulb. Wikipedia says the original version used two 100W bulbs.

Now that I'm thinking about it... 100W bulbs are "illegal" here in the U.S. now, and that's why the Easy Bake no longer uses a light bulb...

But still, a known-wattage bulb seems like the easiest way to experiment with this chamber.

12

I stand corrected on the bulb wattage. never actually used one.

but if all you are doing is drying your pot....er... "solid products" all you need to do is to raise the temperature until the humidity is low. air volume will aid in the speed of drying.

you might want to use a speed controlled fan, and a humidity sensor,
run the fan at normal speed, then slow it down as the humidity drops. once the humidity is less than 50% you might consider your "solid products" dry.

13

Heating pads used in heating Glass beds for 3d printers can reach nearly 100c. My print bed is at 86c right now as we speak. They're relatively cheap, and are flat. You could line each wall with one and not lose any space inside the box. Easily timed with an arduino.

Now reading the other responses a little closer, I never considered herbs. I just assumed he was trying to dry his ABS for 3d printing. It will equalize to ambient humidity within about 72 hours, so the drier it is the better.

Course it may get gooey at these temps.

I need sleep.

14

dave-in-nj:
I stand corrected on the bulb wattage. never actually used one.

but if all you are doing is drying your pot....er... "solid products" all you need to do is to raise the temperature until the humidity is low. air volume will aid in the speed of drying.

Erm ok i used to do something similar with film if anyone can remember that.

Too fast drying would easily cause cracking or curling of my product.

Perhaps that may not be of importance though.

What has this got to do with arduino though.

15

Boardburner2:
What has this got to do with arduino though.

OP wants variable timing so Arduino can be used.

Weedpharma

Edit: thanks Dave (next post) I read out of context.

16

he could use an Arduino to turn on the switch? maybe ?

17

Hi,
Is this the same project?

http://forum.arduino.cc/index.php?topic=373046.msg2572364#msg2572364

Tom.... :slight_smile:

18

TomGeorge:
Hi,
Is this the same project?

http://forum.arduino.cc/index.php?topic=373046.msg2572364#msg2572364

Tom.... :slight_smile:

http://forum.arduino.cc/index.php?topic=373046
not sure why the link would not open

19

the OP posted this twice. same general post, and has only posted twice.

97aaronk , you can buy these dehydrators.

if you want to make a special on, use the incandescent lights,
get a SSR from e-bay that will work with an arduino. search ssr arduino
get a temperature and humidity sensor
get a fan that works on either 12 volts or 5 volts
get a TIP120 transistor to use to control the fan
get a 5k or 10k pot
get a 2 or 4 line lcd display, and a serial backpack for it (still can't figure out why serial LCD is not common)
get a nano and a screw terminal board
get a project box, a case, an enclosure or some such to house the thing

you will need wire, resistors, capacitors, etc

the SSR will turn the lamps/heater on and off
the temp/humidity sensor will monitor progress
the display can show humidity and time,
the pot can be used to set the timer and possibly the desired humidity level.

each step can be done to help you learn.
do the pot input to dim an LED first
then the humidty temperature
then the heater
then the display

20

I have built a similar chamber with temp controller for curing epoxy for fiberglass or carbon layup. For something this size, you'd likely best be served with a halogen bulb around 100W. A small fan can help distribute the heat more evenly.

BongFlyer.