Step 3: Stir bar and casing

Step 4: Test

So finally I added some water in the cup, threw in the magnets, and put it on the stirrer. As fan started spinning the magnets started stirring and w...

My project is also uploaded on the website in English, but it was designed and completed in China, so I think it should be uploaded on the Chinese website once so that more Chinese friends can see it.

Description:

As I was looking through my junk laying around the room I noticed the old USB cooler fan which I have no use for. Then I thought of what I could possibly use it for and I remembered of the magnetic stirrers I have seen used in chemical labs. Unsurprisingly the idea to use a CPU cooler fan to make a stirrer wasn't new and already existed on many online DIY websites, but I decided to make it anyway to show how electronics can be reused in other fields.

Step 1: Take apart the fan from protection case

First I took apart the housing to get the fan itself. It is a standard 5V fan with a USB power supply; if necessary you can also use batteries to power it.

Step 2: Attach the magnets

Next step was to find some magnets. I found smaller magnets lying around, but they were a bit weak. Luckily I also found a pair of old broken headphones, so I opened them up and obtained a pair of stronger magnets. Now the magnets were a bit too strong that when attached to the fan they would attract the magnets used inside the fan motor itself, thus, preventing the fan from spinning. As a solution, I used a small plastic piece to create space between the fan and batteries.