[SOLVED] Problems with Relays, LCD noise

Mainly there are LCD and relays that control electroluminescent wires. It all runs fine for a few minutes. And then I suddenly get a giberish output to my LCD, sometimes LCD backlit turns off and finally everything freezes. I guess it’s a problem with an inductive load of relays, but have no idea how to fix it.

As soon as I disconnect my relays, everything runs fine like forever. No freezes, no troubles at all.
Please, help :slight_smile:

My circuit:

Some giberish output:

EDIT:
It seems like problem is a noise sent from DC-AC inverter that powers electroluminescent wires. When power source of inverter (2xAA) is disconnected, everything runs pretty fine (tested for nearly an hour). What is the idea of fixing that?

SOLUTION:
A simple workaround provided by user TomGeorge. The idea is to have seperate inverters for each EL wire and connect 110V directly to ELs. Then use relays to switch inverter’s DC input instead of switching AC output like I did before.

In your schematic, is the thing marked "Relay" really just a relay, or is it one of the relay modules? By "relay module", I mean something like this:

pert:
In your schematic, is the thing marked "Relay" really just a relay, or is it one of the relay modules? By "relay module", I mean something like this:

Yes, exactly. It is a relay module just like in the picture provided. It has 4 channels, but I only use 2 of them.

My guess is power issue.

Those relays draw more current than uno pin is really designed for, coupled with fact your running whole setup off 2 -AA batteries. Your initial converter might be overheating and causing voltage fluctuations which then garble the project.

Maybe when cool, hold a finger on the (buck booster?) chip and then turn project on and see what happens first, your removal of your finger due to heat or the LCD scrambling.

If the LCD scrambles first I would switch relay to get power from source via a power transistor that is controlled by the uno pin.

If you have to pull your finger off first, try more initial voltage or oversize heat sink.

The relay coil is not powered by the Arduino's IO pins. The pins are only controlling the optocouplers on the relay module, which is well within their current limits. The relay coils are powered from the Uno's 5V pin. But I don't see that the schematic shows how the Uno is powered. I think the AA batteries are only providing power to the EL wire.

pert:
The relay coil is not powered by the Arduino's IO pins. The pins are only controlling the optocouplers on the relay module, which is well within their current limits. The relay coils are powered from the Uno's 5V pin. But I don't see that the schematic shows how the Uno is powered. I think the AA batteries are only providing power to the EL wire.

Uno is powered by 5V usb

Slumpert:
My guess is power issue.

Those relays draw more current than uno pin is really designed for, coupled with fact your running whole setup off 2 -AA batteries. Your initial converter might be overheating and causing voltage fluctuations which then garble the project.

Maybe when cool, hold a finger on the (buck booster?) chip and then turn project on and see what happens first, your removal of your finger due to heat or the LCD scrambling.

If the LCD scrambles first I would switch relay to get power from source via a power transistor that is controlled by the uno pin.

If you have to pull your finger off first, try more initial voltage or oversize heat sink.

Inverters were already included with EL wires when I bought them so they are designed for that and shouldn’t be overheating I guess. All I did, just connected 2 EL wires to one inverter instead of having seperate ones for each EL wire and then taped inverter’s power button so inverter could always stay on :smiley:

And like pert said, it is not an initial power source. Initial is 5V to UNO from usb (forgot to mention that). 2xAA is for EL wires only.

Hi,
The EL wires are connected to a High Frequency inverter designed for the job, what happens if you position the EL and Inverter WELL AWAY from the controller and it wiring?

You have 110V HF inverter output going via the protoboard, bad news, they are not rated for those sorts of voltages and are mixed with low voltage UNO wiring.

So rewire your 110V wires so they are COMPLETELY away from any other wires.
Turn the relay assembly around so the output terminals point away from the controller and keep all 110V wiring on that side.

Noise from the inverter is possibly getting into the UNO and causing it to RESET., or scramble your I2C link to the LCD.

Tom… :slight_smile:

TomGeorge:
Hi,
The EL wires are connected to a High Frequency inverter designed for the job, what happens if you position the EL and Inverter WELL AWAY from the controller and it wiring?

You have 110V HF inverter output going via the protoboard, bad news, they are not rated for those sorts of voltages and are mixed with low voltage UNO wiring.

So rewire your 110V wires so they are COMPLETELY away from any other wires.
Turn the relay assembly around so the output terminals point away from the controller and keep all 110V wiring on that side.

Noise from the inverter is possibly getting into the UNO and causing it to RESET., or scramble your I2C link to the LCD.

Tom... :slight_smile:

Put my 110V wirings away from the breadboard, didn't help though.

What happens if you run it with the relays connected, but the EL wire not connected to the relays?

pert:
What happens if you run it with the relays connected, but the EL wire not connected to the relays?

Successfully ran it for nearly an hour without any troubles (testing before showed that an error occurs in ~7mins on average). As soon as I turned the power source for EL wires on, LCD messed up in just a couple of seconds. So, what is the idea of reducing this kind of noise sent from the inverter?

Hi,
I think your biggest hassle is you are switching high frequency AC, which is not good for those type of relays.

Ideally you should be swiitching the battery DC input, i know this would mean an extra inverter but it may be the answer.

Just to check, just wire the EL wires directly to the inverter you have, and get one of the the relays to switch the battery supply. See if your problem occurs with that config.
It will also allow you to move the inverter well away from the UNO and LCD.

Tom... :slight_smile:

TomGeorge:
Hi,
I think your biggest hassle is you are switching high frequency AC, which is not good for those type of relays.

Ideally you should be swiitching the battery DC input, i know this would mean an extra inverter but it may be the answer.

Just to check, just wire the EL wires directly to the inverter you have, and get one of the the relays to switch the battery supply. See if your problem occurs with that config.
It will also allow you to move the inverter well away from the UNO and LCD.

Tom... :slight_smile:

What a nice and simple solution! Have been testing for a while and seems like it does the trick! Many thanks!