This laptop cooler is designed to work with a 17" laptop (specifically an Asus G73JH) or similar sized laptop to create better airflow underneath. Now my Asus gaming laptop doesnt really need a laptop cooler, but I thought it would be a neat challenge to teach myself how to use AutoCAD 3d to create some complex shapes and explor them as .stl files for printing on my newly acquired Makerbot Replicator 2 through a grant I recieved.
IMPORTANT!! - I designed this cooler to be higher off the ground because of the depth of the fan. I also typically use a USB keyboard when I game so the height of this design is irrelevant for my original application. I am working on designing different legs to create an inclined position for the keyboard to create a better position for individuals using a laptop keyboard.
Why AutoCAD 3d?
I am well aware that AutoCAD is not the greatest program in the world to work on 3d models. There are much better programs and even cheaper ones that make it easier to work in a 3d space. I am using AutoCAD 3d because I am planning on implementing my 3d printer into my middle school technical drawing course and they are learning to use AutoCAD as part of the curriculum.
In the next few slides I will go throught he materials I used along with issues that may occur while printing.
Step 1: Overview of Parts
At the top of this page I have include images of the fan, furniture grippers, potentiometer, heat shrink tubbing, and control knobs that I needed to safely wire and complete the laptop cooler. Pricing seems to be better in store than online.
Furniture Grippers (Lowes)
I got these for about $5.00 each in store. I got these because I loved how they work and they really provide excellent traction.
NZXT FN-200RB (Performance Fan)
IMPORTANT!!! - If you are duplicating this project, make sure the fan is 7.9" x 7.9" x 1.2"
I chose this fan because I wanted the focal point of the laptop cooler to be the fan since there was such a large surface area due to the size of the laptop. This fan also is very quiet and has very little vibration. Also, I have an Amazon prime account which saved me on shippint so I only paid about $13.00 for the fan. The other benefit later on was I didnt have to modify the fan at all, there was a separate cord that connected the fan to the built in pc power supply that allowed me to modify that cable instead of the one attached to the fan.
Heat Shrink Tubing
This tubbing material is necessary unless you want to use electrical tape to insulate your electrical wiring. I like the tubbing because it looks better and creates fewer issues. I got these at Home depot for a collar a pack since you don't need much for this project.
25 Ohm Rheostat Potentiometer
I chose this patricular potentiometer at Radio shack because I didnt want to completely limit the fan speed, but wanted to have some control over the speed. The value of this potentiometer will also be dependent on the power source you are using. I used a .5 amp level 2 transformer I had laying around which was perfect since the Performance Fan only required .42 amps. I also liked the shorter dial on the potentiometer. I also purchased a knob for the top of the potentiometer.
Level 2 Transformer (For Toys)
I happened to have several of these K'nex level 2 transformers for toys lying around and they are perfect for powering this fan. You could probably purchase them online.
Step 2: Electrical Wiring
The circuit for this particular project is not complicated. Its a basic series circuit where the potentiometer (or variable resistor) controls the amount of current that reaches the fan. By limiting the current we control the speed of the fan.
Wiring the Potentiometer
Looking at the picture above, you are only going to use two of the three poles on the potentiometer. The hot wire from the power source will be connected to either of the end poles of the potentiometer, and one of the leads from the fan will be connected to the middle.
WARNING!!! - I highly recommend twisting the wires and using electrical tape to temporarily setup your ciruit to make sure the circuit operates the way you want it to. Fans do not have a hot lead so depending on which way you wire the circuit will depend on which way the fan spins.
So to summarize, the hot wire from the transformer goes into one of the two outer poles of the potentiometer while one wire from the fan gets attatched to the middle pole. Once everything works the way you want, solder everything in place and use the heat shrink tubing. You will then need to solder the remaining wire from the transformer to the other wire coming from the fan. This will complete your series circuit.
Step 3: Modifications to the Fan Itself
Before I could finalize the designs for the fan brackets, I had to modify the stock fan I purchased. If you click on the amazon link below, You will notice that the fan actually has two sets of circular mounting points. There are 4 on the same side as the fan guard and 4 on the side without. the problem is they do not line up and are at separate 90 degree angles.
I also had to grind up some addition obstructions that I have highlighted in the pictures above. I used a dremel alot on this project and makes life soo much easier.
Step 4: Laptop Cooler Parts and .stl Files
UPDATE!! - I have recently descreased the height of the feet that hold up the laptop by 3/4" so that should lower the laptop a bit. Still need to leave about a 1/2" of room for air flow.
Just to review, I did use AutoCAD 3d to make these parts so they may not be as smooth as they would be if created with another program. I used this software because this is the software my technical drawing students will be using next year to create docking stations for their celluar devices.
The pictures above show the best alignment of the parts in Makerbot Desktop. Their are very few issues with printing except when printing the largest piece (fan bracket). I had trouble finding a good alighment that would limit the amount of rafting removal, but would also produce the best quality part without using as much support.
You will also find the .stl files to print the box I used to make my speed control box for the fan. This may vary depending on the potentiometer you use.
NOTE!! - when aligning the "Absolute Final Fan Bracket V2" file in Makerbot Desktop, make sure you go to the scale menu and click convert from inches to millimeters. For some reason the other parts prompt you, but on this piece because of the size it doesn't. Otherwise it will look very small.
Step 5: Basic Assembly
To be honest, the assembly isn't rocket science. The top of the feet part shaped like a dowel gets fed through the hole on the legs. The cap is designed to align with the contour on top of the leg piece so it gets snapped down on top. The fan brackets align typically with the fan mounts.
You should be alright if you just look at the pictures.
You will want to use 4 1/8" diameter bolts with nuts that are about 3/8" wide.
I eventually attatched the legs using super glue, specifically Gorilla brand super glue.
I have also included here the graphic I used for the speed control dial.
Step 6: Final Product
Here are some pictures off the final assembly and how it sets up with the laptop. The pictures of the laptop sitting on the laptop cooler isn't quite accurate since i have recently shortened the legs.
So far everything works extremely well. Please let me know if you have any suggestions.
UPDATE!!! - Since I posted this Instructable, I have made some alterations. If you are using this basic setup the way I currently have it, I have lowered the feet by 3/4" which should lower it quite a bit.
I have also posted a new Instructable that includes parts that work with the same fan brackets, but allow you to angle your 17" laptop. I haven't completely tested this design, but i would say about 70% of it I have been able to test and it works.
here is this link: https://www.instructables.com/id/3D-Printed-17-Lapt...
Thanks for your input!