We’re Fans of Dave’s Fans

Hackaday.io contributor extraordinaire [davedarko] gets hot in the summer. We all do. But what separates him from the casual hacker is that he beat the heat by ordering four 120 mm case fans. He then 3D printed a minimalistic tower frame for the fans, and tied them all together with a ULN2004 and an ESP8266. The whole thing is controlled over the network via MQTT. That’s dedication to staying cool.

We really like the aesthetics of this design. A fan made up of fans! But from personal experience, we also know that these large case fans can push a lot of air fairly quietly. That’s important if you’re going to stand something like this up on your desk. While we’re not sure that a desk fan really needs networked individual PWM speed control, we can see the temptation.

Now that they’re individually controlled, nothing stops [davedarko] from turning this into a musical instrument, or even using the fans to transmit data. The only thing we wouldn’t do, despite the temptation to stick our fingers in the blades, is to complicate the design visually. Maybe that would finally teach the cat not to walk around on our desk.

74 thoughts on “We’re Fans of Dave’s Fans

  1. well i don’t want to be a downer or anything but i don’t like it.
    network control for something you are going to be right next to (and you will have to be right nect to it for any benefit)? pointless.
    3d printing extremely simple parts that could have been made in a fraction of the time with many more simple process and tools but if you spend all that money on a 3d printer i guess you have to make the most of it right? 3d print the base? no just use any old lump of wood lying around that will do!!!
    he bought the fans specifically for this? whatever floats your boat i guess.
    my physics teacher used to parrot on about fans only heat up a room. i guess it depends on humidity vs sweat.

    1. Today everything has to be “smart” and connected to the crap uh i mean cloud and with 3D-printed parts… I just fixed a 80mm fan to one of these cheap base+two alligator clips+(crap )magnifying glass-things i use for soldering (how do you call these??) and plugged it into my lab PSU. Works just fine. Well, finally i added some fan guard to…

      1. so what do you do if you want to use your lab PSU for other stuff? ;) You could use an old 12V PSU to power it. I think mine is from a broken external HDD case.

        I think it’s called a “second hand”. not sure though, things get weird when getting translated.

        It wasn’t about getting the fans connected, but rather about the connecting itself. I’m trying to make sense of the IoT and smart stuff myself, right now everything I do is more like a “dumb remote” for fans and lights. I’m not even logging stuff. Yet.

        1. Just realized that I could take an old HHD and stuff it with batteries as a portable phone charger/12 volt supply. :)

          I am a fan of your fans. It looks like this project was a fun learning experience.

      2. I call them 3rd hands :)

        I too repurposed such things, the magnifier glass strapped with cable ties to a swan neck led lamp for easy positioning, 2 or 3 3rd hands mixed and matched with multiple bases for stability and extra grippers, with rubber stuck under the bases, which comes from inner tyers of a bike. Much more stable and it stays put.

        I use a single 12cm low noise 1000rpm fan with 90 degree angle fasteners from the hardware store as stand to blow away the soldering fumes. I’ve seen the ‘sucking’ variant on here with carbon filters, I may do something similar at some point.

        I like the fan design above, one could make a gradient in airflow, less on the face and more on the body :) That’s one of the gripes of using fans, when working in front of a pc the eyes get too dry.

        One could also add some ir or sonar proximity sensors and control the fan speeds according to measured distance, faster when farther away, the user experiences the same amount of cooling. And turn the fans off when the cat gets too close :) use the sonar high pitch chirp to scare the cat away!

      3. Simpler answer: because it works well.

        1. Uses MQTT. I can connect this to my network, and it will just work. The end. I can also have it trigger on temp or humidity controls (or even, hell, opening my door). Because it is using the standards, I only rely on *my* machines, and not someone else’s (‘cloud’).

        2. The fans and power are easily changeable to something heavier. I could put this in an attic for optimal airflow (temp), or in a crawlspace (humidity). The platform is already there.

        3. I can make something like a environmental chair. Pair this, with the oculus, some IR heat lamps, and even an incense burner. And you now have a full virtual environment. And MQTT easily integrates.

        But “Today everything has to be “smart” and connected to the crap uh i mean cloud”…. Or you’re boorish and insulting because you lack understanding why this is pretty damn awesome.

    2. The 3D printing
      yes, it could have been done differently, but I have a printer, I love to use it and print mostly under a “must be practical” rule. Designing brackets etc. is good training and it’s pretty accurate, took about 20-30 minutes to design (the handle took the most) and then the printer did the rest.

      The fans
      yes I bought the cheapest ones I could find, since I had a picture in my head of 4 fans on top of each other and not 2x 5cm, a 14cm and a 12cm fan. I just had no fans anywhere. I checked my dads stock as well ;)

      The base
      The recycled piece of wood was(/is) a placeholder from the beginning of this project, since there was no controller to design a base around yet. I still have to make a base, I guess – because the board is hanging out. I might add buttons too.

      The being connected part
      I’m lazy. Ever forget to turn off your lights or fans, when already in bed and the remote is on your desk? I have made 10 ESP8266 breakout boards, wanted to get to know MQTT and had a fan project where I pulled the plug to shut it off. This is better :)

      The room part
      the fans were a big help in cooling my macbook air over the summer, in fact mostly the bottom fan, that’s the whole reason why I went with single-controllable fans in the first place.

      1. Cool idea – you really don’t need to justify any of your reasons for making this, or any of your design decisions.

        I’d suggest a motion sensor (either as part of the fan or separate – or maybe several depending on room layout) and have a timer that turned the fan off after x minutes of inactivity in the room. You could even add a temp sensor and only turn it on automatically if the temperature was uncomfortable.

        If you’ve got the MQTT server on the Pi, have you looked at node-red? It’s a nice companion to monitor MQTT traffic (and a whole bunch of other stuff) and act on it.

        Jerry

        1. Right now it would be interesting to have a ‘shutdown fans’ event triggered, when the mac book goes into sleep mode and starts again when woken up.

          node-red looks nice, I was never in to the graphical drag and drop programming, but this looks nice.

        1. The buttons are on the list :) not sure about the lights though, I get easily distracted by stuff like that. And blinking LEDs make me think I missed a call or got an email, thanks to the RGB light notifier in my phone.

          1. Another option would be to add some simple sensors like light, temp, and humidity if you have the IO. You already have the device so why not add some sensors to it if you have the io. The lights where more of a joke:)

    3. You you really do want to be a downer.
      Yes you could make it a different way but you can make most anything a number of ways. Making little brackets with a 3d printer seems like a fine idea.
      Making it connected? Why not? Again someone might just want to do that as an exercise to lear about smart devices. I would add buttons on the device for sure but again esp8266 boards are dirt cheap.
      Will fans make a room hotter? Well yes but will it help cool you? Yes. Unless the room is 98.6 or higher air moving over you will help cool you. Stagnant air near a body will be heated to the temperature of the body by radiation and conduction. The only cooling will be convection and from evaporation of your sweat but again the local humidity will reduce the evaporation. Moving air will cool you. Now if the air temp is above 98.6 then you will only have the evaporation effect.

    4. Yes but if he was abducted by alias and taken to another galaxy he could use a web based app on his smartphone to turn the fans on and off on Morse code and send his galactic co-ordinates. It’s not overly complicated!

      1. .. — / .. -. / … .–. .- -.-. . / … . -. -.. / …. . .-.. .–. / -… . …. .. -. -.. / – …. . / — — — -. / -… .-. .. -. –. / ..-. — — -.. / .- .-.. .. . -. / ..-. — — -.. / … ..- -.-. -.- …

      2. “Abducted by Aliens” is a nice thing to point at on a location clock. That could totally be a thing, use some social network APIs and set the location based on posts (via mqtt of course).

    5. What if I don’t have “any old lumps of wood” laying around, due to the fact my interests are not wood-working but instead are mainly in computers and electronics?

      Is it my inherent interests, or just the fact you have skills I don’t, the reason you feel I shouldn’t be welcome in the maker community?

  2. Sorry to see so much negative comments on a cool idea. Although I fully agree that connecting it to the internet is useless for this device, that’s not the point of the project, I’m pretty sure about that.
    Sometimes projects are just for the fun of it and not for the practical. However… for someone having a 3D printer, a finger or fan guard of some sort would be a great object to be printed and with 4 fans not unimportant. But perhaps he’s still working on that?

    1. I’ve stuck my fingers in fans… the guards are mostly to protect the fans… you either just stop them or they shatter, the only time I’ve got cut is when one shattered then the super sharp broken edge got me.

    2. Thanks for the kind words :)

      Sometimes I hold my finger against the fan to feel alive, sometimes a piece of paper get’s caught… ;) it’s really not that bad though. I would have to redesign and reprint the brackets and buy longer screws to make room for the fan guards – although I’ve never hurt myself (no blood).

      1. Best guards are those chrome wire ones. Two reasons, round edges = less turbulence = less noise and most open area of all guard designs = less restriction and noise…. also they sit above the fan by a few mm, reducing turbulence and noise, some drilled or punched flat ones don’t clear very well.

    1. I’ve used the Arduino IDE to program the ESP boards and the MQTT broker is running on a Raspberry Pi. I still have a motor from a vibrator in a drawer and could print a fitting case for your stimulator as well. You don’t have too use it all the time though, you can still take time for HaD.

  3. These would be sweet as window fans, extract at top, ventilate at bottom if you’ve got sash windows, combined with the temperature logger posted above this added so you can attempt to use control to keep room at steady temperature.

    1. And if you really want to get fancy, you can connect your IoT thingy to a scent release system that will release smells into the airstream. Then when people take a dump on your project on hackaday it can… you know what, maybe that’s a bad idea.

  4. I’d rather have one large fan than four small fans. Although these are apparently fairly quiet, the droning of four PC case fans seems like it would be maddening. So there’s an obvious application for individual PWM control: variable speed control algorithms! Randomize each fan, or better yet synthesize beat frequencies to match your brainwaves. Promote periods of productivity or meditative states, automatically selected according to the time of day. Could be a terrific sleep aid.

    I have an old 7-bladed box fan that’s now a sought-after collectible because its intrinsic harmonics are more restful for some than modern 5-bladed types. Maybe a computer-controlled variable multi-fan could produce the same effect.

  5. I really like this, It is simple apart from the “smart” aspect and I bet it is great at cooling you down. If I was to build this I would have done it placing the fans in 2X2 configuration at the top of a pole. To improve the smart part of thefan I would have the pole rotate on command using a stepper with the option of having it slowly turn 45 degrees either side like a traditional fan automaticity.
    It may be over the top for most but I think this is a great little hack. Well Done!!

  6. I think any ordinary fan, as in ones meant for cooling people not equipment, would beat this at cooling people, and fans aren’t even expensive.

    If you really want network control, you could do that with a proper fan with a triac. Of course fans, by their nature, need to be quite near you to be any use, but mine’s still out of my reach. I’d probably use remote control if it had it.

    How do ordinary fans control their speed btw? The ones with 4 buttons. I expect it’s something simple, low-power and cheap. Maybe different taps on the motor? Maybe that’d be better, of course you’d need 3 triacs (don’t need one for “off”), or at least one per set of taps, perhaps “3” is “1” and “2” together, like in a heater. I dunno. Tempting to just take the case off this here fan over there, actually.

    Dave’s done lots of projects, and they’re often pretty interesting, but I don’t think this is one of his best.

    1. These fans are quiet. 12cm 12v fans are over engineered to have best airflow/efficiency, less noise and are cheap. Typical people fans are optimized by cost/size, with complete disregard of noise and actual air efficiency.
      PWM is needed on cpu fans because they can have a temp difference of 30C in few minutes, so moderating them is nicer than switching on and off manually.

      1. My desktop fan is, I have to say, silent. Perhaps not 0db but I can’t hear anything at all from it, and it’s a metre and a half away. What’s air efficiency? Power-wise, from the size of the motor, it can’t be using too much. It produces more than enough air.

        The 12v 12cm fans I’ve used, and I’ve built lots of PCs, couldn’t compare.

    2. Yep, household fans usually use different motor taps.

      With 4 12V fans, you could maybe have some electromechanical control by switching them between series, series-parallel and parallel.

    3. If you are using a household fan with an Induction motor (only because that is what my fan has) there are a number of ways to control the speed. Limit voltage, limit current Or limit Voltage & frequency, You just need to find what would work best for you design and what components you had or could get.

  7. I had some really powerful 12V 4″ fans, rated to move 50 cubic feet per minute and they spun at 5400 RPM. The downside? LOUD! Over 40 decibles. I took a knife and deburred all the sharp edges on the hub and blades and profiled the four support arms to be shaped to present less resistance. That did reduce the sound level enough I could tell the difference between that one fan and the others, but it wasn’t enough.

    Sadly, my dream of combining them into a 350 CFM grid of fans was not to be. At least I didn’t pay anything for them and I passed them on to another person for free.

  8. Simple to explain the noise. More blades and faster rotation will equal more noise from turbulence. That’s why propellers are two blades. They utilize a large sweeping surface area and enough time for the next blade coming in to get fresh low turbulence air. PC fans are typically very noisy due to the sheer RPM and blade count. You should 3D print an extended duct for the front and back side of each fan.

    1. PC fans have 5, 7, 9 or 11 blades. The low noise fans usually have 11 blades and sometimes 9 on CPU’s.

      A aircraft propeller is completely different because it is designed to move through the air and they’re very loud lol

  9. I re-purposed two 120cm internal fans from an AS400 to blow air over my freezer coils. Small wooden frame, wired them in series (household low voltage circuit is 24VDC), and tied the +ve and -ve ends to the freezer’s compressor (also 24VDC). So the fans only ran when the compressor was active and the coils needed cooling. Lucky the freezer was downstairs, those fans were LOUD.

  10. It is neat to show what you can do, but I tend to agree, if it is going to be right next to you, the wifi remote is kind of pointless, and if the fan moves any air it looks like it would blow itself over. It would be cool to put some slots in the base so you could put some velcro cable ties through it so you could lash it on to something and/or put some neodymium magnets in the base so you can stick it on something.

  11. A friend of mine will soon be moving to a hot climate and is trying to prepare for this transition. A portable cooling system sounds like a great idea for her. I love this article about fans. I also love the designs and find that their other features were brilliantly decided. Something to consider is if they are travel safe.

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