Is a self-powered transmitter possible?

[k.udhay]

This video claims that the transmitter is self powered and hence needs no battery or other electric connection.

Is this possible? I have never come across an electronic device that runs self-powered.

Couple of things I think might happen here:
1. A solar cell in the transmitter?
2. Everytime when someone presses the switch, it converts some of that energy to electricity? Like piezoelectric for instance?

Pl. share your comments.

 

[berkeman]

2. Everytime when someone presses the switch, it converts some of that energy to electricity?

A company that I worked for has self-powered switches that transmit an RF message sequence when pressed. They use a snap spring mechanism and an induction coil to convert the button press to electrical energy to do the transmission.

https://www.easyfit-controls.com/

https://www.easyfit-controls.com/portfolio/easyfit-wireless-switch-esrp-edrp/

 

[k.udhay]

Thank you so much!

 

[russ_watters]

My GF got a couple of these so she could avoid some light switch wiring(similar product). I think they are piezoelectric.

 

[jbriggs444]

$2.69 at Staples.

 

[Vanadium 50]

Is this possible? I have never come across an electronic device that runs self-powered.

https://en.wikipedia.org/wiki/Crystal_radio