Engineering & Technology


Error Proofing (Poka-Yoke)

This is a technique that was invented by Shiego Shingo to ensure that mistakes could not happen during manufacturing. Poka-Yoke in design is about avoiding mistakes. An excellent example of Poka-Yoke design is the UK mains socket, which has safety features that make it impossible to use improperly.

Microwave Oven

The radiation inside a microwave is very dangerous since it can cause burns and damage to the eyes. A switch on the door automatically switches the magnetron (the component that produces the microwaves) to prevent harm.

USB Cables

The shape of USB plugs and sockets are designed in such a way that it is impossible to insert them the wrong way around ,which would otherwise cause damage to the equipment.

Fuel Pumps

Putting diesel into a petrol engine can cause serious damage to the car. To avoid this the refil neck on a petrol car is smaller than that on a diesel car. At the pump, diesel nozzles are wider so they will not fit in the refil neck on a petrol car.


A 9 volts battery (PP3) as used in smoke alarms can only be connected the right way around due to the shape of the different shape of the positive and negative terminals.

Security / Tamper-proof Screws

To prevent unqualified people removing parts of a product that could be dangerous, special screws can be used with heads that normal screwdrivers will not fit in.

Lift doors

Lifts have a sensor called a "light gate" which detects if an object is between the doors and will not let the lift move.

The video below is of an old type of lift called a Paternoster. Do you think it applies Poka-Yoke?