Help with Wonkey LCD

Hey Everyone,

This is my first post. I am brand new to this and I have spent the last couple of weeks trouble shooting this issue without success. I'm hoping someone can provide some insight.

Project Overview:CO2 and Fan Controller

  1. Measures temp and humidity (DHT11),
  2. If temp is above set-point, triggers a relay which powers an outlet which powers a fan,
  3. Measures C02 (CS811),
  4. If temp is below set-point, triggers a relay which powers a solenoid (on 12V power) which releases CO2.

(What appears to be) Randomly sometime after turning on the LCD goes wonky and displays weird characters. Sometimes this is after minutes, sometimes hours or days. Does anyone have insight into what i can try to fix this?
I have attached a picture of my hardware and wiring and the code I'm using.

thanks in advance for any assistance anyone can provide.

C02 and Fan Controller.txt (7.37 KB)

Are those diodes in the ground lines from the relays, solenoid and DHT? If so, what are the diodes purposes?

Welcome to the forum.

Please read the post at the start of any forum , entitled "How to use this Forum".
Then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

The diagram you have provided is very confusing and would be better drawn with proper symbols and pin labeling.
What is your power supply?
Can you please post a picture of your project?
Do you have a DMM?
If so can you please measure the 5V going to the LCD and other components?

If you remove the fan, does the fault still occur?

Thanks... Tom... :slight_smile:

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