One of issues we observed on our project controls were quite frequent unpredictable & restless movements. Those are appearing when there is no (or constant) signal being sent to devices, but it looks like they still receive some noise there and behave quite erratically.

After a consultation with Richard, he introduced us to the world of Opto-isolators, being also addressed as Optocouplers.

So what is it that Optocoupler? As many times before, I’ll leave it to Wikipedia to answer:

An opto-isolator (also called an optocoupler, photocoupler, or optical isolator) is an electronic component that transfers electrical signals between two isolated circuits by using light. Opto-isolators prevent high voltages from affecting the system receiving the signal. Commercially available opto-isolators withstand input-to-output voltages up to 10 kV and voltage transients with speeds up to 25 kV/μs.


Jameco Electronics also comes with a very nice picture, explaining how things work.

Checking this further with Richard, he approved us to buy several following DST-1R4P-P optocouplers. While picture shows 5V -> 24V, we’ve also ordered 3x 5V -> 5V and 1x 5V -> 3.3V.

I took a screenshot of the connection diagram for reference:

All arrived in a good shape & under 2 weeks.

Soldering all that thing as per instructions took a while and was honestly quite tedious. However result was very satisfying!

Installed, finally! Sebi says that it feels much better. More precise and less shaky. On other hand he also kept working on some signal clearing on the receiver side, claiming that it is his change – not optocoupler’s one. Well, time will tell.

This is our first test of it, just to check if well connected. (Optocoupler is that blinking device inside that cabling maze, at the end of video.)

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