night mode with Sainsmart USB relay board

[ErnieBall]

I'm still trying to wrap my head around DOF and how to set everything up.

If I went with a sainsmart USB relay board to controll solenoids (and button LEDs), would the night mode toggle via Pinscape Pico still work for those solenoids?

Or would they have to be controlled directly by pinscape?

[mjrgh]

The Sainsmart USB boards have their own direct USB connection, so they would completely bypass the Pinscape software running on the Pico, and thus Pinscape's Night Mode would not affect the Sainsmart ports. So Night Mode wouldn't work for those.

To make matters more confusing, Sainsmart ALSO makes a different kind of relay boards WITHOUT the USB connection. Those are designed for connecting directly to GPIO ports on a microcontroller like an Arduino or a Pico. With those, everything would go through the Pico, so Pinscape's Night Mode would work for those ports.

So as long as you go with the second type of relay board - the kind with direct GPIO ports, and no USB port - you can use Night Mode. It'll also simplify your DOF setup, since you only have to set up the Pinscape Pico board in DOF. DOF doesn't see the Sainsmart directly in this case because the Sainsmart board isn't part of the USB environment.

One important thing I should add is that relay boards in general aren't the best solution. Relays are mechanical, and they tend to wear out pretty quickly. I've seen a lot of people post in the virtual pinball forums that they have to replace those boards every year or so due to their short operating life. The thing to look for instead is MOSFET boards. Those are essentially exactly the same as the non-USB relay boards as far as the setup goes, so they don't add any complexity on your end, but MOSFETs are solid state devices that should last forever. (You can still break them by overloading them with too much voltage or current, but as long as you don't do that, they won't ever wear out from routine mechanical wear the way relays do.)

[ErnieBall]

As always, you taking the time to explain things in detail is much appreciated. I try to read as much as possible to understand before I have to ask questions. Unfortunately I lack some baseline electronic knowledge to understand everything I read.

I have seen the concern about Relais for this application, but the idea of having an affordable option that is known to work, without me having to chose the right part with the right specs, was appealing.

Could you or someone else, link a mosfet board that would work with 12v solenoids? I'm planning to use power from my PC PSU, so 5v and 12 are available.

[mjrgh]

I haven't tested any of them myself, so I'd hesitate to offer a specific recommendation, but there's a recent thread on vpforums from one of the big contributors there that's mostly about the MOSFET boards:

https://www.vpforums.org/index.php?showtopic=56035

He tried a few different options, and it looks like this is the one he decided on:

https://www.amazon.com/dp/B0DZP1NCVW?th=1

Basically anything that claims that it'll work with a Pico should be good. Most power MOSFETs will be safe up to at least 24V and 4A, but many of them will go much higher - the product page should list the limits. It's always good to leave a margin of safety with these things, maybe 50% extra headroom on voltage and amperage. For example, if your solenoid is 12V and 2A, get a MOSFET board that says it's safe for at least 18V and 3A. And you can always use something with higher specs than you need - if you need 12V, and the board says it's good for 50V or 100V or 10,000,000V, that's perfectly fine. The higher the better, basically. The only other thing to watch out for is "Pico compatible". The big divide in microcontroller boards (which is what the MOSFET board are designed to work with) is between the Arduino world, which is 5V, and nearly everything else, which is 3.3V. The Pico is very nearly a proxy for "everything else" these days, so most MOSFET boards that will work with 3.3V will specifically mention Pico compatibility on their product page, and therefore I'd look for that when choosing a board. It certainly doesn't mean that a board WON'T work with Pico if it doesn't say so outright, but it's a better bet that it WILL work with Pico if it mentions Pico by name.