Can you remember getting frustrated while plugging in USB devices in your desktop and/or your laptop? The USB socket has a treacherous esthetic property which fails an extended definition of poka-yoke. Let’s take a look.
Not regarding which angle you’re looking from, the USB connection socket looks like a perfect rectangle. The difficult part is on the inside: the small rectangular connection point can go only one way in. Also the USB connections are located next to each other with only millimeters apart so that it really hard to take a look.
Twenty years ago, when the USB gate was created, it was probably meant to be poka-yoke. I had many discussions at school during our Quality Major about why it was not, so I feel kinda released that they finally had the insight themselves.
Poka-yoke is a Japanese term used for mistake-proofing or also fool-proof design. When you create something fool-proof, you can not use it in a wrong way and create defects.
Examples of poka-yoke
- New lawn mowers are required to have a safety bar on the handle that must be pulled back in order to start the engine. If you let go of the safety bar, the mower blade stops in 3 seconds or less.
- The dryer stops operating when the door is opened, which prevents injuries.
- The driver must press the brake pedal before starting the car.
- Electrical sockets can only be used in one way.
- Induction cooking plates only work with certain types of pans.
- Toys for children in their first years.
Examples of lack of poka-yoke
- A CD-ROM can be inserted upside down.
- You can fill up your car with the wrong fuel because the different fuel pumps have the same handle.
- A pencil sharpener can be used for sharpening pens.
- Manual fill of soda drinks.
- Renewing your cartridges in a CMYK printer.
Proposal: an extended definition of poka-yoke
To me poka-yoke is not successful if it only prevents damage by mistakes. The definition lacks some basic user-friendliness. That’s why I would like to add following to the poka-yoke definition:
poka-yoke is mistake-proofing design that makes the use very obvious and native (even from first time use).
Using this definition, following are examples of failed poka-yoke:
- Bathroom sinks with the little hole near the top of the sink to prevent overflows where the overflow leads to your floor or closet.
- A light socket can only take in certain types of light bulbs, but if you would put your finger in it, you get elektrocuted.
- A floppy disk can only be inserted in one way, but it is not obvious which way.
- Just like the USB connection, the Ethernet connection tried to be poka-yoke but failed in it (the same reasons as USB). Yes, you cannot insert it wrong, but it’s not obvious in which way to insert it.
- And last but not least: the USB connection gate. The connector can only be inserted one way, but it’s not obvious in which way to insert it.
How will USB change?
The new USB will have a ‘Type-C’ connector that can be plugged-in in any direction. The smart socket works in any occasion. Sitting on your knees behind your desktop looking at the USB connection socket will be of the past. Getting frustrated by trying to plug in the second USB device in your laptop will also be of the past.
Other advantages of the new USB will be:
- One universal micro socket (opposed to the many sockets that are available today).
- Faster power charging for connected devices.
- Other connections (like eg. firewire) will be deprecated (the ambition of the new USB).
- High speed connectivity and data transfer.