Not the high power electronic anti-spark (AS) switches. I’m referring to the low power button switches used to turn on ESC’s, BMS’, and other devices.
What features could this button switch have to make it work with just about any device? A few things I thought of are…
Both normally-open (NO) and normally-closed (NC) contacts.
Power and ground connections for an LED in the switch.
A place to solder on the correct current limiting resistor for the LED.
Selectable momentary or latching operation.
What else?
A couple of questions…
Do we really need a normally-closed set of contacts? Is it just so we can have the button in its “relaxed”, not-pressed, position to close the contacts and turn on the device (for shock resistance)? Or do some devices genuinely need to have a connection broken in order to turn them on? That is, they need a normally-closed switch, one that opens when pressed?
Do we actually need both momentary and latching operation? Can the devices that use a momentary button press to turn on and another momentary press to turn off (Unity ESC?) use a latching button instead?
Edit…
Please assume that the switch we’re discussing will not bounce off or on or change its position if hit by a pebble, branch, or tactical nuclear weapon. I’m just talking about the switch’s theory of operation, what it has to do and how. Making it vibration/shock/impact proof is a different discussion.
I use latching switches for turning my 12V buck on and off in boards for lights. I now use power supply rocker switches, because the round, latching push-buttons don’t hold their state under vibrations. They’re not rated for 50V DC I think, but so far so good.
Do we need a universal power switch like what you describe? Having different kinds for different applications seems fine to me… Although what you describe seems like a fine list of requirements to me.
And personally, I will always prefer momentary switches for turning vital electronics off, where you need 3 seconds of contact. I’m not taking the chance of a pebble hitting my switch and that being enough to turn my board off
Sorry, I’m not sure what you’re saying here.
You have a device that takes a long momentary touch to turn it off? Would a latching button (assuming that it could not bounce off) also work?
Yes, the flispky smart antispark and stormcore (probably Unity as well), need you to push the switch for like 3 seconds for it to turn off. (Someone with a vesc mk 5 can also chime in, I don’t personally know.)
I don’t know if those devices could work with that. And if they did – idk if I would personally trust it. A pebble could still trigger it It would probably be fine, but I don’t see a reason to change.
Implementation is another discussion though. This one is just about theory of operation.
But, for your design, what happens if the device needs momentary contact? Push the button twice?
How do you ensure power-up into a known state?It handles this…nvm.
How do you create a NC setup and a NO setup?
My only concern for a latching switch handling on/off would be riding in the woods and having a branch press it accidentally.
This is the only reason I’ve thought of that makes a timed momentary switch more helpful… Requiring a few seconds of press to turn off the board instead of immediate.
I did read this caveat but wasn’t sure if branch was greater than or equal to pebble.
It would probably be fine, but I don’t see a reason to change.
This one is just about theory of operation.