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





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

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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.

Step 6: The Magnet and the Power

I make my own stirring magnet covering a little magnet with hot glue.
In other photos, you can see the power.



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    Interesting project

    Interesting. I have used a very similar circuit to drive a laser diode, also scavenged from a CD/DVD burner.

    A note to others who read this: this circuit should not be used to drive a bare laser diode! Laser diodes are current controlled devices that are non-linear and this circuit is a voltage regulator. In other words, it is near impossible to drive a laser diode with only this circuit without risking blowing it up (laser diode current shoots up to insane amounts with a very small change in voltage). If you want to use this circuit, be sure to add a current limiting resistor like you do for LEDs, otherwise I suggest another circuit that is current regulating (have a look at Dan's high power LED driver instructables for dirt simple and cheap ones).

    Some here might reply that it worked for them, well good for them. They most likely used a laser diode module that has current regulation integrated (some look just like a plain laser diode). I dont know if the diodes in CD/DVD burners are usually packed in a module or not.

    you can actually use the lm317 as a constant current generator by using a slightly different circuit

    surely you mean a 12 volt DC power supply, not AC

    i am not being a downer, but, that magnet rotating under the aluminium plate produces eddy currents, and thus puts off a lot energy as heat i suppose... (much like an induction cooker).. if u substitute the aluminium plate with something else, it would be much more efficient...

    It is just a prototype. I mean it was. You can see in my projects the 2S magnetic stirrer.

    Very nice - I've been wanting one of these for ages. However, for maximum use, you need to build one with a thermostatically controlled hot plate as well!

    If you tell me how to make the hot plate, I'll do it.

    How would it work for mixing epoxies or small amounts of hardening liquids ? it looks good and the "Ible" quite good !