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I'm using Wemos D1 mini with enabled and connected Wi-Fi and photocell connected to A0 with a 10K voltage divider.

Because of ESP8266 behavior with huge current spikes up to 400mA, photocell acts like a random signal generator.

I wonder if it's possible to eliminate those silly voltage drops/current spikes.

I've tried adding 5 parallel connected 470uF electrolytic caps as close to ESP as possible, but it didn't help so much.

Thank you for sharing your ideas

asked Aug 12, 2017 at 9:34
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    \$\begingroup\$ needs a schematic to clarify the problem. None of us has the schematic of your boards in our head, so helping you is impossible! Please add a schematic to your question that clarifies what you're looking at. \$\endgroup\$ Commented Aug 12, 2017 at 9:36
  • \$\begingroup\$ Here it is drive.google.com/file/d/0Bxj9aybXvEBRRGEyZUgyVlZyLWs/… \$\endgroup\$ Commented Aug 12, 2017 at 9:49

1 Answer 1

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If you want to stabilize just the signal then you could add a shunt regulator just to the Photocell part of your circuit. Use a TL431 to regulate the voltage on the Photocell (the ref 2.5 V should be sufficient with a 390 Ohm resistor) from the 3.3 V regulator on the MCU.

enter image description here

If the signal still varies too much, then you could try increasing the capacitance on the 3.3 V regulator output (I assume you added your extra capacitance to the 5 V supply).

answered Aug 12, 2017 at 11:25
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