Hi all,

I want to build/develop a handheld reader for Mifare card, based on P89C66X. This device is powered by battery.

I'm in the stage of designing and collecting information.

I want to add "Long Press To Switch ON/OFF" features to this devices. It's just like our handphone on and off features.

But I don't know what the circuitry/component involved to make that features. I try to googled but have no luck.

Did anybody know about this, please advice

Thanks
Parif