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Topic: digital switch ? with arduino . how to do it (Read 184 times) previous topic - next topic

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

LarryD

#1
Oct 27, 2016, 06:42 pm Last Edit: Oct 27, 2016, 06:44 pm by LarryD
Are you familiar with switches and outputs?
http://www.gammon.com.au/forum/?id=11955






.
No technical PMs.
The last thing you did is where you should start looking.

g43q654wutrjh

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


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

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...
Use fricking code tags!!!!
I want x => I would like x, I need help => I would like help, Need fast => Go and pay someone to do the job...

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https://github.com/septillion-git/FadeLed

g43q654wutrjh

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


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...

septillion

#5
Oct 28, 2016, 11:53 am Last Edit: Oct 28, 2016, 11:54 am by septillion
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.
Use fricking code tags!!!!
I want x => I would like x, I need help => I would like help, Need fast => Go and pay someone to do the job...

NEW Library to make fading leds a piece of cake
https://github.com/septillion-git/FadeLed

Grumpy_Mike

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.

septillion

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
Use fricking code tags!!!!
I want x => I would like x, I need help => I would like help, Need fast => Go and pay someone to do the job...

NEW Library to make fading leds a piece of cake
https://github.com/septillion-git/FadeLed

g43q654wutrjh

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

Grumpy_Mike

Quote
a relay uses to much power
How much is too much?
You can get very low power relays you know.

dlloyd

#10
Oct 29, 2016, 03:36 am Last Edit: Oct 29, 2016, 04:40 am by dlloyd


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).

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