Human Factors and Ergonomics Society Europe Chapter
B
etter Ergonomics - Example 10

Stove controls
top
middle
left under right under

Click on key to start


We had a stove with a glass cooking surface. The 4 burners were switched with conventional knobs, but to the right of them was an area for slow cooking, or keeping things warm. This was switched by touching a spot at the front of the glass surface. However, placing anything that had substantial capacitance - a pot, a tetrapack of milk, whatever - over this area switched on the heating element. While it didn't get hot enough to glow (as the other elements did), it was hot enough to be dangerous.

We recently replaced the unit with a very similar one, except that this one has two points, rather than one, that have to be touched. The first one, the key, arms the circuit while the second turns the unit on. They have to be touched in sequence, so setting something on both doesn't switch on the unit. Also, if the first one is touched but not the second, it shuts itself off after a few seconds. Above is a diagram of the new, better, arrangement. There are 2 circles, one labelled with a key, which has to be touched first, to 'unlock' the switch. This causes the other circle to flash; touching it causes the flashing to change to constant illumination and turns on the heater. The second circle has to be pressed within about 3 seconds; otherwise the circuit returns to off. The rectangle above the two circles illuminates when the heater reaches a certain temperature and remains lit as long as this temperature is reached, whether or not the heater is on. (That is, it warns you not to touch the heating surface.)
Perhaps not ideal, but certainly safer than the old model that only had one switch.

submitted by Richard Cavonius

Next example
Previous example

Back to index of bad ergonomics