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Pololu push button switch + piezo switch


#1

Hello

I have two boards:


I tried to use them with piezo switch and 14,8V li-ion battery - currents max 2-3A

Here is what I have:

  • default state is always ON after connecting battery
  • piezo switch is able to turn it ON (after manual OFF with micro switch on the board) but cannot turn it OFF
  • built-in micro switch is working ok with my finger, no problem to turn it ON/OFF…

Is there a way to get it working with shorter pulses from piezo switch?
Is there a way to make the default state OFF?

I can solder these smd components so there won’t be a problem to change some resistor or capacitor…

Thank you for advice


#2

Hello.

I am sorry you are having trouble with your power switches. We have not tested our power switches with piezo switches, so they might work with some, and not others. As for the default state, do your switches default to ON without the piezo switch connected?

-Jon


#3

Hi Jonathan

Yes, both boards start with default state ON no matter if piezo is connected or not.
Piezo button gives shorter impulses compared to built-in tact switch.
I do not know the way to change the latching circuit’s reaction time, but there are some R and C components near mosfets (RC filter?)…
I wanted to use your bords for underwater flashlight switch (that’s why I chose piezo button)


#4

As you have seen, a piezo switch is not quite the same as a physical switch making contact between the two pushbutton nodes, which is what our circuit is designed for. Without knowing more about the specific pulse your switch is producing, it will be hard to recommend a better switching circuit. Can you let me know what piezo button you are using?

-Jon


#5

Hi Jonathan

Indeed piezo switches are not so friendly…
I use this switch:
http://www.onpow.com/en/product/product1915.html
I was so desperate to build CD4013 flip flop and saw almost the same situation… (tact switch works, piezo has hickup)

Going back to pololu boards: would it work to put n-mosfet (source and drain) instead of tact switch nodes and control the gate with piezo?


#6

That datasheet really doesn’t give us much to work with (I don’t see any specification of the duration of the on pulse), and unfortunately, we do not have any immediate solution for you. The MOSFET instead of the physical switch won’t work.

-Jon