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Topic: LCD scrambles after switching breaker (Read 2176 times) previous topic - next topic


That is looking immensely better.  :smiley-lol:

I am still concerned about that lone wire from the main board to the relay module as it should as previously explained, have a pair.  But then I note you appear not to comprehend the relay module.  It already includes the driver transistor and opto-isolation so your driver transistor is not needed and only causing more trouble.

Here is how you connect the relay module directly to the Arduino:

Note that the power supply wires must go as a pair to your 5 V power supply while the "IN" and "Vcc" wires (but not ground) go together to your Arduino, separate from the power wires.

So you can see how it works, here is the circuit of the relay module.

Filers are not effective against impulses, and proper wiring is the critical matter here.  :smiley-eek:

Just for reference, here is the eight relay module which may better resemble the connections on the two-relay module you have!


Ok i will have a better look at your post tomorrow. That lone wire you see is only the ground for the relays board and i still need to mount the 5v wire, it got loose around the moment i stopped.


That lone wire you see is only the ground for the relays board and i still need to mount the 5v wire, it got loose around the moment I stopped.
I presumed it was one of a pair which would later be mounted.  The point is that you do not need (and do not want) the extra transistor you have mounted to control the relay board as the relay board already includes it with additional opto-isolation.  The two power wires for the relay go direct from the relay board to the 5 V power supply, separately to other wires - nowhere else - and the control wires go direct to the Arduino and nowhere else!

So you have some more re-wiring to do!


Mar 26, 2020, 07:22 pm Last Edit: Mar 26, 2020, 07:24 pm by Thomassen85
Today i tested it and for some reason the red led goes on and stays on  :smiley-confuse:

The display is working with the correct text and also the temp sensor works correct. When i heat up the temp sensor to the point the red led normally should come on, the text on the display turns jibberish.

At this moment i cant see what is the issue with the red led circuit.

Btw the relays i have not connected yet and if i disconnect the arduino the red led also stays on.
The wires from the breadboard to the arduino i still have to straighten but first all needs to work.


You have me puzzled.  Which red LED?

Unfortunately we do not seem to have an overall schematic of your project,


How about this?

Not all components are on the iCircuit so I had to improvise.


I replaced the transistor and that solved the issue  :)
Ok back to straighten the wires, almost finished.


Mar 28, 2020, 08:24 pm Last Edit: Mar 28, 2020, 08:27 pm by Thomassen85
When I power up the psu the display goes on together with yellow led (temp to low needs heating) and the relay. Works like it should.
The loop has 3 seconds delay and after the first time display shows scrambling, after 2nd it shows all blocks after 3th a single block bottom right.
The LEDs, relay and temp sensor all seem to work fine.

The setup is the same as before only now it's flat on the breadboard and wires straight.

i checked multiple times but everything is soldered exactly where it should.

Maybe display broken? Tomorrow I will upload a simple sketch for display only to see if that makes a difference and to exclude my sketch from the issue.

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