Air Circulator - a Screen-bar Like Top Mounted Desk Fan

Watch the Video

If you are not a text-reading person, you can get a quick overview on this project in the video above.

Why I am making my own fan?

It is getting hot recently and I really want to add a fan to my desktop. As a Maker, for simple electronic devices like a desk fan, I usually made them myself as I can ensure its design stability as well as make sure it will be high quality enough to run for a long period of time.

However, the issue I am getting here is that my desk is really too messy. I don't have an empty spot to put my newly designed fan if I am gonna to make one. That is why I am starting to think about a strange idea.

"Maybe I could mount the fan on top of my monitor like a screenbar?"

That is why I am designing this concept prototype to try out the concepts. In simple words, it works, but it still need some improvements in the next iterations. In this Instructable, let me share with you the design I got right this time and what you can avoid if you are planning to build your own :)

• Switches
• Mini USB port / 2.1mm DC Jack
• SMT Capacitors
• LED, Resistors for Power indication
• XL4005E or XL6009 (depending on your configurations, I pick this from my pile of electronics from previous projects)
• 4010 DC blower fan x 6 (I get them from a recycle store for really cheap)
• Custom PCB for mounting the fans

The fans I am using here is 12V 0.15A. When stacked in 6, they are drawing 12V 0.9A. So if you are using the boost circuit design (which I will mention later), please ensure you have a USB power supply that can handle at least 5V 3A.

Gathering material for this project might be a bit tricky. The first and most obvious item you will need is a custom PCB made. I usually recommend this as the first step for any projects that require a custom PCB as this is usually the part where it take the longest to arrive.

I print my PCB at JLCPCB as they offer a free PCB every month if you are designing it on EasyEDA. So I ask nicely and they agree to help me manufacture a PCB with a special form factor that is much larger than what they usually printing. Interestingly though, this time the PCB just takes 3 days to print and another 2 days to ship to my place, which is an interesting experience for me after printing so many PCBs from different manufacturers.

If you are interested in printing your own PCB, you can get one over here.

You can also directly open it in EasyEDA Editor with the following links

https://oshwlab.com/tobychui/fanbar

https://easyeda.com/editor#cmd=new_schematic,cmd_for_project=5f222506428040bfaa1bb1ccd8ff7dc7

Next, the step is quite straight forward. With all the parts arrive, now I need to solder on all the parts. The fans are glue on top of the PCB using hot glue and solder the wires to the corresponding power pins on the PCB.

The PCB power circuitry for the fan consists of two power source. One is the input power (5V) and another one is 12V that is boosted by a XL6009 buck boost converter. However, I think I got a fake one online which cannot actually output the 4A it claims on its website. That is why later I switched over to another module with XL4005E which only provide buck conversion. In order to compensate for the required voltages for the PCB to operate, I added a 12V input jack for the HIGH power mode and use the buck converter to provide 5V for the LOW power mode.

After the circuit is tested with a multimeter to ensure nothing shorts, I powered it with a 12V 2A power source. The fan is much quieter than I expected and I can easily toggle HIGH / LOW power mode from a switch on the left hand side. I also left a 6mm hole in the middle of the PCB for mounting it to the top of my monitor using a cheap ball joint I tear down from a selfie stick. However, I still don't have idea how to mount it to my monitor yet as I just notice my monitor didn't have a flat backplate...

At least from what I get from this project, I know my design is working regarding the two voltage HIGH / LOW Power switch, as well as the design and traces width regarding the power lines on the PCB. However, a few things that I will need to improve in the next iterations

• Large PCB like this, although it is really nice to look at, is a bit expensive to produce. Maybe the next iteration, I will split it into two smaller PCBs
• I might need a separated power boost and power input to make sure the boost converter do not overheat when powering all fan with USB 5V which is boosting to 12V
• I need a slightly better mounting mechanism that fits my monitor.

Anyway, if you want something similar to this, feel free to use the materials and schematics above to build your own! I will see you in the next Instructable :)