Need Help on Modifying Atomizer Circuit

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sunjayw
 
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Joined: Sun Dec 04, 2022 1:39 pm

Need Help on Modifying Atomizer Circuit

Post by sunjayw »

Hello, Friends:

I have a circuit from a ultrasonic mister. The units does not operate immediately when powered. The switch needs to be pressed to turn on the mister. It also has a 4 hour timer. The atomizer disk does not work when connected to power directly. I would like to get the unit running once connected to power and disable the timer. This would make it so much convenient to integrate with my pico setup. Any hints and suggestions are appreciated.
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adafruit_support_mike
 
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Re: Need Help on Modifying Atomizer Circuit

Post by adafruit_support_mike »

sunjayw wrote: Sun Feb 05, 2023 10:42 pm The atomizer disk does not work when connected to power directly.
Yeah, that won't work. The disc is a piezo element that needs to vibrate at a specific frequency.. some are designed for 113kHz and others for 2MHz. You need to drive the element with a square wave at the appropriate frequency.

The control board sends power through the piezo element through an inductor (T1) using a mosfet switch (Q1). Given the RGB LED on the board, the switch, and your description of a timeout period, it sounds like the IC is a microcontroller programmed to read the switch, generate the appropriate drive frequency, control the LEDs, etc.

It would probably be easiest to modify the board by replacing the existing microcontroller.. either by desoldering it, or just cutting the traces that connect to it.. then connecting another microcontroller that runs the mister the way you want.

You'll need to find the driver frequency for the piezo element, but then you can tap into the connection to Q1.

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