When I got my Nokia E71 smartphone, I also bought a hands-free device for it: the Sygnet Bluetooth Handsfree Carkit model BTS600. This actually works quite well – it wirelessly identifies the phone on my belt when I get in the car, and until I leave the car all calls are routed to this device. Throw in voice recognition based dialing, and it’s convenient indeed.
Still, the controls of this elegant space age device – it really looks like a miniature flying saucer, doesn’t it? – embody some basic human engineering errors, ones that are all too common in other products; we can call them control cloaking and control overloading.
By control cloaking I mean making controls that are all but invisible and indistinguishable from each other. The BTS600 has only four controls: a power switch, and the three marked with +, – and a handset symbol. The user needs to identify the last three rapidly, at a glance, while driving a motor vehicle. So what would you do to make this easy?
I know what I would do: I would design large, obvious buttons, each differing markedly from the others in color (for daytime use) and in shape (for night time driving). Something like the three skyscrapers in the Azrieli Center in Tel Aviv – one round, one triangular and one square, and all impossible to miss…
Not so the good engineers at Sygnet. They made the three buttons flat, and blended them into the device’s surface so elegantly that you can barely make them out – with tiny labels that are hard to read even when parked. And the device’s perfect circular symmetry makes it impossible to locate the buttons by their positions relative to its edges.
And then there’s the matter of indicator lights. The device has two lamps: blue and red. You’d expect these to be visible from all angles; which would be the case if they protruded outside the casing. But instead they are sunk deep inside, under the clear plastic ring around the speaker grille. Again, very elegant – but quite invisible unless you look straight in.
Don’t miss the control overloading post coming up next!
Take the image at right, the list you have to go through to select a country for a new contact in Outlook and other applications: it opens on a list of ten countries, of which one – Argentina – may be even remotely likely to be inhabited by business contacts of yours. You can scroll down, of course… and in the next ten you find even greater concentrations of business partners, like the entry for the 
The proliferation of these gadgets has created a real problem, and home electronics makers are responding by creating R/C units that can control more than one item; most typically, a TV set and the DVD, PVR or VCR feeding it.
Everyone knows that the 
