The Lightning Leap


I built a classic ‘buzz-wire’ game with wood and wire for the FOAL Farm animal sanctuary’s summer fair called ‘Catch the Cat’. In this game, losing players heard the sound of a dog barking, while winners heard a cat meowing.

The Meccano version allows players to win real money, while losers cause the game to ‘catch fire’ by illuminating two silk flamelights. The name of the game was inspired by these flamelights and the shape of the buzz-wire.

Coin slot

When a 2p coin enters the coin slot, it travels down a chute where it activates a switch to start play before falling into the top of the coin dispenser. An electromagnet pulls a short rod across the coin slot to prevent further coins being inserted.

Coin dispenser

Many ideas for the coin dispensing mechanism were tested, but it became apparent that none could fit inside a 5½” square tower as originally intended, so the towers were increased in size by two inches and heightened. This made it much easier to fit the flamelights, electronics and other mechanisms, but also made the project more expensive.

Coins collect in a tube of three cylinders, held in place such that no bolts can obstruct the flow of coins. This design was inspired by Brian Leach’s Belly slot machine model.

A gap at the bottom of the cylinder allows a single 2p coin to be dispensed for every full movement of a cam, while a micro-switch actuated by a cam on a 1:5 ratio gear allows five coins to be dispensed in total.

The coins in the cylinder sit on a balance so that should they run low, the mechanism will stop and there can be no further play until the dispenser is refilled. In use, with a sufficiently difficult buzz-wire course, this situation should not occur, and the dispenser should eventually overflow with further coins falling into a hopper.

Buzz-wire and wand

The design of the game allows players to begin from either end of the buzz-wire. Each end is electrically isolated from the casing and the buzz-wire. The dual-loop design of the wand serves to increase the game’s difficulty so that the buzz-wire course can be less complex.


The sequence of events during the game is determined by the state of 15 relays inside the left-hand tower. Because of the power draw from the two flamelights and the electromagnet, the game is supplied with 4A at 12V DC.

Sequence of events

Please refer to the circuit diagram, bottom right.

  1. The Wand rests at either end of the Wire.

    Either the Left or Right Safety Buffer relays are actuated.

  2. An inserted coin actuates the Coin Slot Switch so that both Coin Slot latching relays latch on.

    The Coin Slot Cover Coil actuates to stop further coins being inserted into the coin slot.

    Either the Left or Right Safety latching relays latch on.

  3. The player plays the game with only two outcomes possible (step 4 or step 5).
  4. The Wand touches the Wire.
    1. The Game Over latching relays latch on.

      The Game Over flamelights are lit.

    2. The player returns the Wand to either end.

      Either the Left or Right Safety Buffer relays are actuated.

      The Reset relay is actuated, cutting power to the Coin Slot latching relays.

  5. The Wand touches the opposite end from which it started.
    1. Either the Left or Right Safety latching relays latch on.

      The Wire Enable relay is actuated so if the Wand touches the Wire it will be ignored.

      The Payout motor runs and the Payout lamp is lit.

    2. Five coins are dispensed and the Payout Complete switch is actuated, cutting power to the Coin Slot latching relays.
    3. The Payout motor continues to run until the Payout Complete switch returns to its initial position.
  6. The game is now reset ready for the next play.


The flamelights are non-Meccano items from Luxa Flamelighting and contain fans which blow air up past orange halogen lamps into the silk ‘flames’.


A full prototype of the right-hand tower internals was initially constructed to confirm that all mechanisms would be likely to work correctly in the finished model. Particular thought was given to providing easy access for maintenance, so the external casing of both towers can be easily removed.

New and used Meccano parts were then purchased, with all painted parts being stripped and repainted with either black or lavender enamel spray paint.

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