Small piezo electric crystals are embedded within the frame of the kitchen scales. As a weight is added, a current is generated, sufficient to drive the LCD screen read out of the weight.
-- jonthegeologist, Oct 12 2004

blink and you miss it?
-- po, Oct 12 2004


true. a halfbaker who lives with me also suggests that the greater the voltage generated, the larger the weight, so just some kind of weight to voltage conversion tabel needed within.
-- jonthegeologist, Oct 12 2004


As I understand the piezoelectric effect, the crystal would only be able to power anything while the weight was changing. Once the mass has been sitting on the scale long enough to stop moving and thus be read as a valid weight ("settling time" in scale lingo), the crystal's charge will likely have been depleted by the electronics that are trying to measure the voltage in the first place. Probably. Maybe.
-- half, Oct 12 2004


maybe it could charge a tiny battery whilst the weight is in motion - then display the weight of the object once it's stopped.
-- jonthegeologist, Oct 12 2004


You could use quartz crystals for the heavier things ang nitrogen tri-iodide for anything weighing less than a gram. +
-- sartep, Oct 12 2004



random, halfbakery