How to DIY Your Own Magnetic Stirrer V2 (better Than First Version)




Introduction: How to DIY Your Own Magnetic Stirrer V2 (better Than First Version)

About: I enjoy making things by myself, trying to make this world better.

After I've published the first instructable about how to make a magnetic stirrer and after the constructive criticism I've got, I decided to make a new Magnetic Stirrer, an improved one.
Then I start the research for what materials should I use for it. I make the circuit, the design of the case and then I assembled it.
I hope you will like it, and by the way, you can also use it in many ways.

What did you make?
I made a Portable Magnetic Stirrer that can be used in the chemistry lab, home or everywhere you want yo use it. It is more efficient and it has more features than first version so as it would be a pleasure to use it. As I said above, it could be use in many way, not only as a magnetic stirrer. 

How did you make it?
Making it wasn't very hard, but to make one you need patience and time, patience for possible errors that can appear during you make it, and time for work. I started searching for a case for it, not too small, not too big. Then I continued seeking for a geared motor, which is little and efficent. After I've got it, I search for a metal disc and some strong magnets. When I finished getting all things I need (you will find a materials list next step), I made the circuit, I chose a design for the case and I painted it.

Where did you make it?
I made it home and at school, during breaks.

What did you learn ?
By making this project, I learn that almost everything can be recycled and reused for other porposes, like my project. Almost everything piece of it was recycled. The geared motor is from an old CD-ROM, the case is a CDs case...It was a bit tricky to make it customisable, but not impossible. And it was a challenge for me to make the circuit as small I can.

Let's start the work.

Step 1: Materials Needed

Materials needed for the circuit:
- 3x2 cm perf-board
- a LM317 Terminal Adjustable Regulator (recycled)
- wire (preferably colored)
- 4 LEDs (preferably super bright and colored)
- 4 female connectors
- a 5KΩ potentiometer
- 3 x 1KΩ resistors (recycled)
- a 240Ω resistor(recycled)
- a 10µF polarized capacitor (recycled)
- a 0.1(100n)µF capacitor (recycled)
- a panel mount 2.1mm DC barrel jack
- a CD-ROM(DVD-ROM/RW) geared motor (recycled)
- a 9V battery clip
- a 9V battery
- a 12V DC power supply with 2.1 mm jack
- a 1N4007 diode

Other materials needed:
- a CDs case for 20 CDs (recycled)
- a black paint spray
- duct tape
- a round piece of steel
- a round piece of glass(bigger than the case's diameter)
- shrink tube
- 20 cm of filled transparent plastic tube(0.3 cm thick)(recycled)
- 40 cm of plastic hose (0.5-0.7 cm thick, preferably colored)(recycled)
- hot glue
- solder wire
- 8 x 3mm screws(recycled)(one screw with 2.5 cm height)
- 5 x screw nuts(for 3 mm screw)(recycled)
- a small cooling radiator(you can get it from the processor of a video card)
- easy slide pads
- 2 x HDD magnets(recycled)
- 5 x 3 mm thick round magnets(5 mm diameter)(recycled)

Tools needed:
- Cutting tools
- Hot glue gun
- A drill

Step 2: Designing the Stirrer Case

First thing you have to do is to choose a design for your case. I chose honeycomb because I think it will give to case a futuristic design.
Searching on Google Images, you'll find a lot of patterns and designs for your case.
After you found or created your design, cut down the "head" placed in the middle of case(OPTIONAL). Instead of it, I will stick an Instructables sticker or you can stick there an other piece of plastic.
After that, clean the case. 

Step 3: Stick the Duct Tape

Stick duct tape around the case.
Then draw the pattern or the design on it.

Step 4: Draw the Pattern

After you draw the pattern on it, cut down the unnecessary duct tape.
After that, make two holes, one for the barrel jack, and one for the potentiometer. You have to choose yourself the best place for the holes.
For the barrel jack hole, you need a 12 mm diameter hole, and for the potentiometer you need a 6.6 mm diameter hole.

Step 5: Paint the Case

Now it's time for painting. Ensure that the case is clean.
I used black paint spary usually used for painting cars.
After painting it, remove the duct tape and apply a varnish on the case.

Step 6: Make the Circuit

First, let me tell you how the circuit works.
When the electricity flows in the circuit, you can increase the voltage via the potentiometer. So when the potentiometer is turned to maximum, you have maximum voltage.
How works the barrel jack DC ?
When the power supply isn't connected, the magnetic stirrer use the electricity from battery, and when you connect the power supply, it goes on DC from power supply. So you have to solder both positive leads on the big contact, I mean the positive from battery and the positive from the circuit, the negative lead from battery clip to a smaller contact, and the other negative lead to the other smaller lead. For better understanding, I will show you how to solder them in a photo.
I used a efficient geared motor, so to obtain a high speed you don't need to take the potentiometer to maximum.
At the ends of first four wires that makes the links between the 1K resistors - LED and LED-Ground, solder the female connectors so you will can change the first two LEDs.
To cool the LM317 during the stirrer is working, i put on it a little cooling radiator modified by me. I fix it with a screw and a screw nut. You can see it below.

Step 7: Modify the Gear

I modified the gear to be able to insert the round piece of steel on it. I make four holes in the middle of the gear and the round sheet, three holes with 0.5 mm distance between them and a hole in the middle of this triangle of holes.
Then I fix them (the gear and the round sheet) inserting three screws and after that, I put them on the support.

Step 8: Modify the Bottom of Case

You may cut down the "tower" that was support for CDs so as your magnets will not touch the top of the case.
After that, fill almost the whole rest of the "tower" with hot glue, and when it is cold, make a hole and fix the geared motor there with a screw and a screw nut.
When you finished that, make three holes on the perf-board and three holes on the bottom of case, and fix the circuit.
Then fix a female connectors group (a "positive" wire connector and a "negative" wire connector) on the bottom of case with hot glue, and an other group on the opposite side.
Stick four easy slide pads on the bottom of this part of case.

Step 9: Insert the Transparent Filled Tube on the Top of the Case

Make two holes aligned, which have 3 mm distance between them. After that, bring out the fourth and fifth LEDs through these holes and fix they with hot glue.
Put shrink tube on both LEDs, insert inside the shrink tube the tube, be sure that the transparent tube is touching both LEDs and then heat the shrink tube.
Stick a sticker in the middle of top.

Step 10: Make the Chemicals Protector for the Case

Take the round piece of glass, align it on the case and make some notes.
After that, take three transparent easy slide pads and stick they on the glass so as it will be fixed, will not anymore be able to move.
Take the bigger tube, make a straight cut on it, fix it on the glass's edge, then stick the ends of it (the tube) with superglue.
This thing will protect your stirrer against chemicals's action.

Step 11: Assembling It

When you finish all steps, it's time to assemble this device.
Insert the 9V battery in the battery clip. Be sure that the potentiometer is turn on minimum.
You will know that the circuit is working when you'll see that the LEDs are turned on.
Put the top of case over the bottom of case,
Put the chemicals protector over the top of case.
Then test it with a stirring magnet bought or made by you. You have to align the magnets until they are spinning the stirring magnet.
That's it.

Step 12: Improvements Towards V1

I personally think that V2 is better that V1.
It is more stable, more efficient, is portable, lighter, cheaper. But it's true that you have more work to do.
By the way, you can use it as a night lamp.
Please leave a comment below about What improvements should have the third version?.
You can see the first version here ->

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1 Person Made This Project!


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6 years ago

Please make me one and let me paypal you for parts and labor. I want one but building it is a little past my abilities. I need one for mixing e juice. I mean is it powerful enough for that?


Reply 6 years ago

It depends on the magnet you use. You need a strong one so the magnetic stirring rod doesn't fall behind while it's moving through that thick VG. It needs to stay perfectly aligned with the magnets on the motor or it will get thrown off. Best to use a hot water bath so the VG is more fluid and it mixes faster with the other ingredients. I am currently designing a combined solution for this that I might sell to other e-juice manufacturers if you are interested.


Reply 6 years ago


When I place the magnet on top of my 5v DC computer fan, it stops the fan spinning?


Reply 6 years ago

It shouldn't. I saw on youtube a lot of people making magnetic stirrers out of computer fans and magnets.


Reply 6 years ago

I was very surprised myself, as I also have seen other people using this technique with no issues. I wonder if it is the magnet or the fan design. The magnet is a N52 grade Neodymium Magnet NdFeB. The fan is a 5V Computer Cooling Case Fan 8025 USB 8CM Fan 1300RPM. The magnet will stop the fan when it is within 2cm, does't even need to be touching the fan. Any ideas gratefully received. Maybe the fan is driven by magnets and the poles are interacting.


Reply 6 years ago

I'm glad you like it so much, but unfortunately I made this device years ago. Now I'm studying ICT Engineering and taking a break from building devices. It's really easy to make one, you only need some scrap electronic parts, some basic knowledge about circuits and a little imagination essence.


6 years ago

brilliant design and i enjoyed making it. few questions though. there wasn't too much explanation on the diagram and how you constricted the circuit. Maybe you can mention important points like pointing components in the wrong direction? although we can see which components run in series and parallel but just to mention that as well.


7 years ago on Introduction

that's amazing - great work! I want to make one now myself. Thanks for the detailed info and pictures too - very appreciated!


Reply 7 years ago

I'm glad you like it.


9 years ago on Introduction

Nice, tight, efficient design.

I particularly like your use of as much recyclable material as possible.


Reply 9 years ago on Introduction

I hope that you're not the only one who like my project.


9 years ago on Introduction

Much better than previous! Well done, Andrei!
That's the way: make something that work, then make it better!

Two small corrections: the diameter of "filled transparent plastic tube" is 0,3 cm and the diameter of "plastic hose" is 0.5-0.7 cm. In your text this dimensions are too small.