payWave and PayPass by definition should work both ways. Pity the cards are probably not coded to accept the gratitude an anonymous benefactor can deliver.

Throwing money around just got to a whole new dance level.
-- wjt, Mar 27 2017

On the viability of RF energy harvesting http://drop-kicker....g-bluetooth-beacon/
[notexactly, Mar 27 2017]

Those cards are probably powered wirelessly by the reader. What's the power source in this scenario?
-- notexactly, Mar 27 2017


A tiny shake generator or maybe piggybacking off background wifi energy.
-- wjt, Mar 27 2017


I like the concept of donors being able to add funds to your account easily ... so definitely the power issue needs to be resolved.

Background wifi energy sounds like magic to me though. Will I have to keep shaking my card constantly in the hope that somebody will take pity on me and send a donation my way?
-- normzone, Mar 27 2017


Modulation is a type of shaking. Shaking the EM shakes. A vibration is just a more specifically described shake.

Cellphone app wallets could account virtual cash to be throw'n around . I do not think a card would be too much of a stretch.
-- wjt, Mar 28 2017


It would be nice, if the card built up charge, on it's capacitors, when you made a shop transaction.
-- wjt, Mar 28 2017



random, halfbakery