digital switch ? with arduino . how to do it

i have a separate device that has a push button switch.

is there a simple way to use the arduino to trigger the switch?

like a relay or like a transistor or is there a way without?

for example a led torch, the switch is not switching the power to the led only switching (triggering) an IC to turn on the torch.

thanks

Are you familiar with switches and outputs? http://www.gammon.com.au/forum/?id=11955

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sorry I don't understand what your comment has to do with my question ?

g43q654wutrjh: i have a separate device that has a push button switch.

is there a simple way to use the arduino to trigger the switch?

like a relay or like a transistor or is there a way without?

for example a led torch, the switch is not switching the power to the led only switching (triggering) an IC to turn on the torch.

thanks

You have to be more precise. Yes, probably it's possible but what is the best/easiest method we can't tell. The "switch" might be a tiny switch on a remote or a massive 400V 3-phase switch. Both switches, both controllable from the Arduino but the solution is quite different...

pretty sure I covered that in my example

"for example a led torch, the switch is not switching the power to the led only switching (triggering) an IC to turn on the torch."

= LOW POWER ...yes like a remote.

thanks

septillion: You have to be more precise. Yes, probably it's possible but what is the best/easiest method we can't tell. The "switch" might be a tiny switch on a remote or a massive 400V 3-phase switch. Both switches, both controllable from the Arduino but the solution is quite different...

But that still doesn't tell us everything. What does it switch? To GND? To 12V? To 5V? What is the rest voltage etc. Just "low power" doesn't cut it ;)

And you say, for example. But keep in mind another "example" might need a complete different approach.

The low risk approach is to use the Arduino to turn on a relay and then wire the relay contacts across your switch. That way everything is isolated.

The wiring to do this is shown in LarryD's second diagram which shows a relay being driven from the Arduino through a FET.

That indeed always works if you choose a relay that can handle the voltage and current.

Cons of that: -Slow, so you cannot switch it fast -Probably way over complicated for a lot of cases

a relay uses to much power need something to keep the power down maybe a transistor but not sure which will be best

a relay uses to much power

How much is too much? You can get very low power relays you know.

You can loose the diode once you know the polarity for button connections. The "+" terminal connects to the collector, "-" terminal to emitter. Can determine polarity with multimeter (or trial and error).