Introduction: Electric Cappuccino Stirrer From Recycled Stuff (at No Cost!!!)

This is my description of a hand stirrer I made by using only recycled parts. It runs on 3V, cost me 0 pesos (yep, no cost!!) and is made 100% out of recycled parts.

You can use this hand stirrer to make foam in your cappuccino or macchiato coffee. Or simply as a mixer, fine powderer, etc.

MATERIALS

  • A metal wire, about 10 cm long and 1 or 2 mm in diameter, could be a big clip. It should be hard but moldable, and not too heavy.
  • A small flexible spring.
  • A motor (I took one from a broken CD player)
  • A tube-like container with open caps in which the motor fits tightly. I used the plastic tube in which some pills come.
  • A battery pack and some kind of push-button
  • Wire, batteries, and tools

Step 1: Build Rotor, Motor, and Battery Pack

  • ROTOR:
Bend one end of the metal wire creating a circle (ca. 1 cm in diameter) as shown in the picture and add the spring to this circular part. Remove any part of the spring that remains out of the metal circle, since it would increase the mass moment of inertia. Give the final shape to the metal wire (see picture, it's so hard to explain!!!)

  • MOTOR:
Connect two wires to the motor, and make these two wires go through the container you chosed for your motor. Make sure the motor fits tightly.

  • BATTERY PACK:
Connect the wires (coming from the motor) to two 1.5V batteries with some kind of push button in the middle of the circuit. I used a battery container which fits well in a hand, with a push button made from a small copper foil attached to one side of it. In this way, my thumb finger is left in a suitable position for activating (or not) the circuit.

Step 2: Put Parts Together

Now attach the rotor to the motor. Make sure they bind strongly and that the axis of the rotor and the motor make a continuous line (ie they don't make an angle). If this is not the case, then the axis of the rotor will precess in bigger and bigger circles, untill its bond to the motor will break.

As you can see in the photo, I used that kind of clay which hardens like metal.

Step 3: Make Foam!

Take the stirrer with your good hand (mine is the right one) and the battery pack / controller with the other. Introduce the stirrer in your coffee or whatever and make the motor run. In order to create a good foam, the spring must rotate in the interfase between liquid and air.

Make sure that you don't touch any hard object with the spring (like the walls of the cup or a spoon you may have) as this may bend / brake the stirrer.

Better foam...
...is produced when you have denatured proteins and/or lipids in your solution, since they make up the walls of the tiny bubbles. So normal hot milk in your cappuccino will be the best choice if you want foam on it.