I'm pretty new to electronics, I'm more of a computer guy.

I followed this tutorial to build a vibration sensor. My circuit looks like below.

When I turned it on everything worked, but within a few minutes I noticed a burning smell and my microcontroller stopped working ever since. I suspect I fried the onboard voltage regulator. I tried providing 3.3V to 3.3V pin, now the ESP8266 module is heating up.

I am afraid to use a new microcontroller to fry it again with the same circuit.

What am I doing wrong? I checked for a short circuit, my soldering looks okay. Do I need a resistor to D0 of SW420?

enter image description here

  • 2
    \$\begingroup\$ +/- 5V? that means you effectively connected 10V to the 5V input... ya that would do it. Did you measure the input voltage 5V to Gnd at the module? Or is it just an oddly labeled schematic? \$\endgroup\$
    – vicatcu
    Sep 24, 2020 at 1:11
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    \$\begingroup\$ maybe something weird happened with the buck converter, since it requires 18 V between the input pins and you supplied only 9 V \$\endgroup\$
    – jsotola
    Sep 24, 2020 at 1:25
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    \$\begingroup\$ Did you measure the buck converter output before you connected to the ESP8266 module? It should be 0V (not -5V) and +5V for G and +5 inputs respectively. \$\endgroup\$ Sep 24, 2020 at 2:34
  • 1
    \$\begingroup\$ Thank you everyone for your comments. My schema was wrong in my original question, I edited with the correct one here. @ChrisStratton: Yes, my board is not actual ESP8266, it's Wemos D1 mini. I measured the Buck convertor output, the output is 5V to the ground. \$\endgroup\$
    – ramesh
    Sep 24, 2020 at 3:30
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    \$\begingroup\$ @tlfong01 please stop cluttering the page with irrelevant comments, this ongoing habit of yours across many questions is quite problematic and needs to stop \$\endgroup\$ Sep 24, 2020 at 4:07


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