DIY Solder Fume Fan using old PC Case Fan

[Intoxicus]

I figure instead of spending $30 CAD plus I can use an old case fan to make a solder fume fan. I even have some carbon filters handy by chance.

The catch I'm running into is that the simplest way to do this involves buying a 4 pin PWM fan header to USB adapter that only allows 5v.
Being that the fan is 12v it will run, but in a less than ideal manner.

What's the least complicated and least costly way to be able to plug the fan in and get full 12v, maybe with some PWM control over fan speed?

[Dillpickle23422]

I wanted to do the same thing, but I honestly just used an old laptop fan, wired it to usb, (it only needed 5v) and use it for now. I'd like to make one out of a normal case fan though, so I'll keep this thread in touch too

[Intoxicus]

There are ways to do it that involve like actual work and research. The parts would likely be inexpensive and it would be more about how long it takes for them to arrive. 

I rethought my search term and found a cable that is too expensive that will do the job.

Edit: I didn't think Amazon.ca would actually carry anything like this. https://www.amazon.ca/Converter-Keenso-Adjustable-Voltage-Step-up/dp/B07PQKL9SX/ref=sr_1_7?dchild=1&keywords=5v+usb+to+12v+step+up&qid=1620135899&sr=8-7
 

That should what's needed to get it to 12v for full fan rpm. There's also a potentiometer that makes it adjustable. 

I'm hoping someone knows of a "shortcut" solution that won't require me to refresh my forgotten high school electronics classes, lol.

[minibois]

With these sorts of projects, people usually just source a +12V power supply with a barrel jack (think the sort of power supply your router might use).

That supplies +12V, you just gotta plug it into your power outlet. You can even wire up multiple fans on a power source like that.

Example: 

(Of course this goes over the entire process of a third hand, but also incorporates multiple +12V fans).

[Intoxicus]

Just now, minibois said:

With these sorts of projects, people usually just source a +12V power supply with a barrel jack (think the sort of power supply your router might use).

That supplies +12V, you just gotta plug it into your power outlet. You can even wire up multiple fans on a power source like that.

Example: 

(Of course this goes over the entire process of a third hand, but also incorporates multiple +12V fans).

The idea is to use as much of what I have available already without buying too much new stuff or spending much money at all.
I'm small scale enough I don't need to get too big or fancy.

I would also prefer to be able to adjust fan speed if possible and that step up board I found has a potentiometer already integrated.

[tkitch]

Do you not have random power bricks around?  Ask a friend, I'm sure someone you know has a box of them in the closet.

[minibois]

11 minutes ago, Intoxicus said:

The idea is to use as much of what I have available already without buying too much new stuff or spending much money at all.
I'm small scale enough I don't need to get too big or fancy.

I would also prefer to be able to adjust fan speed if possible and that step up board I found has a potentiometer already integrated.

In the past I've come across this project to use PWM to control the fan speed:

https://howtomechatronics.com/how-it-works/electronics/how-to-make-pwm-dc-motor-speed-controller-using-555-timer-ic/

That still requires some sort of +12V input and of course the PCB and components (plus some soldering)

 

I suppose a step up/down board could work too for DC control though.

How did you plan to supply power, if not through some power brick? USB on your laptop/PC and then a step up board?

Have you considered the power draw max of USB?

[mariushm]

Eh , usb can do 5v at 0.9A ... it's fine. Most motherboards give up to 1-2A on a group of ports, so again, it's fine. 

 

ideally you'd use a step-up dc-dc converter to boost 5v to 5v..12v or even higher... but with the risk of damaging the fan.

You can buy premade boards for 2-3$ 

if you have some electronic shops around and want to make your own, you could probably buy a regulator chip and the components you'd need for a couple dollars. 

*34063 or *33063 are some very cheap "jellybean" voltage regulator chips .. add inductor, diode, some ceramic capacitors and resistors and you can make the circuit on a prototyping board.

There's online calculators for the parts example http://www.nomad.ee/micros/mc34063a/ , and even software applications ... example : https://sourceforge.net/projects/mc34063uc/

 

example with the online tool  (note you don't want Ipk to be above around 1500mA, closer to 1000mA is best,  it's limitation of the chip's internal transistor ): 

 

 

But it's usually easier to just source a small transformer or a laptop adapter and use a basic linear regulator like LM317 or 7812 or whatever to get 12v from it. 

 

[airborne spoon]

so you currently have a 12v fan lying around correct? PWM for a solder fan is unnecessary just have it going full tilt and it will work just fine.

then you are overthinking this, just power that thing off any old 12v power source. be it an old wall wort from an external HDD or old router or any old random plug. 12v is the most common voltage for stuff so finding 12v that you can hook up to for a short period of time should be super easy. You could also use your computer PSU just shove the bare ends of the fan power into a empty MOLEX plug for power. You can also use the 12v car battery, the possibilities for 12v power are excessive.

[Intoxicus]

On 5/4/2021 at 8:14 AM, minibois said:

In the past I've come across this project to use PWM to control the fan speed:

https://howtomechatronics.com/how-it-works/electronics/how-to-make-pwm-dc-motor-speed-controller-using-555-timer-ic/

That still requires some sort of +12V input and of course the PCB and components (plus some soldering)

 

I suppose a step up/down board could work too for DC control though.

How did you plan to supply power, if not through some power brick? USB on your laptop/PC and then a step up board?

Have you considered the power draw max of USB?

Plug the USB cable into a standard USB Wall Wart. I want to have a PWM fan wired to USB so I can plug it in like any other appliance.

Wire the fan to the USB step up and then USB to wall wart. Technically the wall wart is a form of power supply.

I also want to do this properly and not have a fire hazard of a fan while keeping it as simple and inexpensive as reasonably possible.

Sure I could take some "shortcuts" and risk burning the apartment building down that houses more people than only myself.
But I think I will play it safe and do it properly.

Y'all trying to tell me to wire it directly must like making that magic smoke escape or something...

I haven't even ordered any part of anything yet. Still in the research phase and there's other stuff that's higher priority.

Btw I'm on the Autism Spectrum and fan noise can be a serious sensory thing for me if it's hits certain ranges and pitches. If it makes any sounds or vibrations that I can't deal with changing the speed can help with making it something I can actually use. I wound up spending too much money on ML120s from Corsair because I couldn't stand most other fans. Amazon must have been wondering wtf was going on when I was returning fan after fan because the noise was in the wrong range.