Topic: Mechatronics/Robotics

World’s simplest electric train!




Build the worlds simplest electric train with only some wire, a battery and magnets!


Observe the relationship between electric current and magnetic field strength in this fun little circuit! When the train (magnets and battery) make contact with the copper wire, a short circuit creates a high current. This high current creates a magnetic field in the wire which pulls the train along by the magnets!


  • Exposed Copper wire (make sure it doesn’t have enamel coating!)
  • 1.5V Alkaline Battery battery (AA, AAA, etc..)
  • Neodymium magnet discs (plated with metal) – 2 or more



Let’s start by making the coil. Make a long coil by wrapping the copper wire around something cylindrical that you can find in the house (Pipes, candles, cooking utensil handles, etc). Note that the coil size should be larger than the size of the battery and the diameter of the magnets (but not too much bigger)


Place your magnets in a stack so all the poles of the magnet line up. Split the stack in half so you have two magnet stacks and use a pen to mark the top of both stacks of magnets (Note: this means that when you place one stack on top of the other, they should be attracted to each other, not pushing away!)


Get the two stacks of disc magnets and place one stack at either end of the battery on the terminals. Make sure that the marked surfaces are facing outwards like so:
| N-S | N-S | [BATTERY]- | S-N | S-N |


Place your little battery magnet train inside your copper wire loop and it should be pulled through to the other side! If it doesn’t work, try feeding it through from the other side of the coil.

Have fun with it! Try looping your coil so your train runs forever (or at least until the battery runs out).