Bouncing, using logic signal to control Pushbutton

2 questions about Pushbutton Power Switch LV:

  1. I need to power the device by motion. When someone picks it up it should power on. I am planning to use tiny mercury switch ( I know they are not safe :smiley: ). Will the Pushbutton Power Switch LV reliably turn on? There will be a lot of bouncing in mercury switch. I have read something about connecting
    one side of the button to ground and the other side to the switch pad that is closer to the edge of the board. Will this eliminate bouncing problem?

  2. Also in another application I need to power a device by a logic level (3.3V) pulse coming from another device with the common ground. Can control push button be replaced with a signal? Do I need to add a trans to amplify current? Can you provide schematic so I can understand it better?

Thank you.


  1. I think what you are describing with the mercury switch wouldn’t really count as bouncing. The modification you are describing will work for only turning the switch on; you would then have to turn it off some other way, and the mercury switch could still override that other way.

  2. No, a separate logic-level signal will not work. If you have something else like that, you shouldn’t need this switch at all: just use that signal to directly turn an MOSFET on or off.

- Jan

I will be using OFF input to power off device apter period of inactivity. At this time mercury switch will be calm an off. So I do not want the control push button to switch device off. I just want to confirm that the control push button can be connected between GND and the pin closet to the edge? Also if power is on, does constant triggering of the mercury switch affect it?
Thank you.

Yes, the modification described should make the circuit capable of only turning on from the mercury switch.

- Jan

Thank you for reply.
Another question: After I put device down it is possible that it will be in a position where mercury covers the switch contacts. What happens if OFF signal comes when contacts are closed? Will it still power of the device?

If the mercury switch is in the on position, you will not be able to turn off the circuit.

- Jan