How to Make a Magnetic Stirrer That Doesn't Cost Like a Professional One

I needed a magnetic stirrer for my chemistry lab so I made a cheap one that looks almost like a professional one, but doesn't cost very much.
It is made from recycled parts from an old CD-ROM, a printer motor and things from an old CRT screen board (like resistor).
The things you need:
- a CD-ROM metalic case (or what case you want)
- a piece of aluminium sheet
- 10 screws (3 mm diameter)
- 6 screw nuts (for 3 mm screws)
- 2 circular magnets (1 cm thick, 1-1.3 cm diameter)
- a 5.5 cm circular aluminium sheet
- a little passive heatsink (optional)
- a printer motor (almost any motor could be used )
- 1 little screw for motor
- a LM317 chip
- one 0.1 uF capacitor
- one 10 uF capacitor
- one 5K potentiometer
- one 240 ohm resistor
- a universal board for electronics (4 cm width x 2 cm lenght)
- a 12 V AC power supply
-a knob

Step 1: Step 1

Let's begin!!!
Firstly let's drill some holes.
Drill the small holes with a 3mm drill bit, the big one I drill with a 10 mm drill bit and the smallest with 2.5 mm drill bit.

Images have indications about lenght and width, so don't miss them,

Step 2: Step 2

Let's make the circuit.
When the circuit it's done, bend down the potentiometer.

Step 3: Step 3

Here are the magnets and their support.
Drill through the center of circular aluminium sheet.
I used a plastic support for more stability.

Step 4: Step 4 - Assembling

Step 5: Step 5

And there is it. It's done and assembled.
Hope this tutorial was useful for you.
You can use it for stir almost everything.
As stirring bar you can use a magnetic bar from CD-ROM or you can buy a coated one that not reacts with other materials, even neither with acids.