variable speed fan for cold smoker

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sudo

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Ultimate Geek
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#298438 17-Jun-2022 13:29

I want to replace a cheap USB fan with a variable speed/timer controlled one on my cold smoking cabinet.

Most of the time the fan needs to run at a very low speed, to reduce the amount of smoke exhaust but keep airflow to minimise condensation.

I have an ESP8266 and was thinking of a hooking up a computer fan (something with speed control)

Can I use use a fan from an old computer, or is there a specific type to get?

The other thing is power feed. The ESP runs off 3.3V or USB, but the fans I looked at all seem to be 12V.

Do I need a separate power supply?

Or can someone suggest a better solution.

mdf

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#2930934 17-Jun-2022 14:12

For a completely different application (fan in a server cupboard) I use one of these: https://www.ebay.com/itm/112174066548

You can set them up to run according to temperature or manually - suspect you will want the manual speed control. It's just with a potentiometer. There are other fancier versions, you just need to match three or four wires with the fan you are using.

sudo

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Ultimate Geek
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#2930953 17-Jun-2022 14:36

That looks interesting, but the presets are way too high

I also want the fan to go faster as it get cooler (like overnight) to reduce condensation.

TP1 TP2 Accelerating temperature Full speed temperature
OFF OFF 35℃ 45℃
ON OFF 40℃ 55℃
OFF ON 50℃ 70℃
ON ON 60℃ 90℃

concordnz

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EMT (R)

#2931016 17-Jun-2022 16:28

Your requirements are the direct opposite of what everything is designed for (99% of fans work on higher temperature = run faster)

You would need to program an inverted curve into the ESP8266

concordnz

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EMT (R)

#2931018 17-Jun-2022 16:30

And yes, standard computer fans are 12v.

Your other option, is to buy 'laptop coolers' and rip the fans outta these - these run on USB - I've done precisely this when I needed USB compatible fans.

sudo

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#2931041 17-Jun-2022 17:51

Yeah, thats why I mentioned the ESP. As I can define detailed schedules, and later add a temperature sensor, so it can trigger the fan when the internal temp goes above a threshold (like that board that @mdf mentioned).

You can find similar sample programs on arduino.cc, but I would need dual power supply spaghetti and Im not sure if it would work.

The trouble with the USB fan, is it runs at one speed (and I would assume the laptop cooling ones do the same). So one that can be run at variable speed is going to work better in my environment.