I am planning to operate 2 mini servos with an Arduino when a particular signal is detected. The 2 signals that are sent (from the system I am monitoring) are a dry contact closure and also 12VDC. As far as I can tell from looking at code samples and forum posts suggesting needed components, neither is easier or better than the other. Seems like a "6 of one, half dozen of the other" situation. I think I favor less components over less code. Your thoughts??
Read the topic "How to use this Forum".
Also search for topics that use those signals and how to run a servo. There are tons projects where You can pick up the things needed.
I would prefer the dry contact switching to ground an Aduino pin with pinMode INPUT_PULLUP.
The 12v will require lowering to the 5v max for an Arduino pin and will have a wire with voltage on it running around your project.
It’s inevitably ‘safer’ to keep external voltages ‘away’ from input pins.
If you want a bit more current to push a longer cable, just use an external pullup.
If you’re losing too much voltage drop over a long or noisy cable - you mat want to consider a higher voltage as you started out - with or without an opto-isolator, or a twisted pair to address any noise injection issues.
THANKS cattledog for tip. All the searching and reading of posts and Arduino websites had me thinking I had to use a relay to sense a contact closure. I'm gonna try your idea cause I definitely didn't want to mess with kicking down the 12v signal to 5v.
I definitely didn't want to mess with kicking down the 12v signal to 5v.
Hardly a problem!