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Topic: Using relay without a microcontroller/emulating HIGH pin (Read 403 times) previous topic - next topic

XGamer223

Hello everyone,

so I have a 5V DC controlled relay that I can use on my Arduino with a single pin - no trouble with that.
But I want to use the relay in something else, which is waay too simple so it's not really worth getting an arduino for that.

I would like to control the "in" pin on the relay without any microcontrollers. Is there a way to do it? If I'm not mistaken if the pin is HIGH the voltage on it is 5V, am I right with that?

So, is there a way to control the data pins without a microcontroller... IF the pin is 5V while it's HIGH the best way to do it would be to connect a 5V supply to the IN pin.. or is it more complex than that?

Thanks in advance.

DVDdoug

All you need is voltage across (and current through) the coil.   I'm guessing you have a relay board with a driver circuit?   In that case, yes, just apply 5V to the "in" pin.    (Plus, you need a ground connection.)

Wawa

Some relay modules need 5volt (or 3.3volt) on the 'in' pin.
Other relay modules need the 'in' pin connected to ground for the relay to work.
Can't tell without seeing a link to the relay module.
Leo..

XGamer223

All you need is voltage across (and current through) the coil.   I'm guessing you have a relay board with a driver circuit?   In that case, yes, just apply 5V to the "in" pin.    (Plus, you need a ground connection.)
Yes there's a board with random components on it, so it's not just a classic relay with a + and - pin... it only turns on/off when you operate it using the IN pin.
Here it is: https://www.botshop.co.za/product/5v-relay-module-with-status-led-diode-and-transistor-trigger/

XGamer223

Here is the link, sorry for not posting it before.
https://www.botshop.co.za/product/5v-relay-module-with-status-led-diode-and-transistor-trigger/

outsider

The relay coil needs 75 milliAmps plus a few more for the switching transistor, where is your 5 volts coming from?

XGamer223

I'm probably going to use a 5V phone charger, probably with 0.7A rated.
My plan was to connect + and - from the phone charger, and extend the positive line to the IN pin to turn it on... is that going to work because I'm afraid that I might ruin the transistor on the board with the relay.

Wawa

The input of the relay module is meant to get 0 or 3.3volt or 5volt (from an Arduino pin),
so connecting the input to 5volt or ground is ok.
Leo..

XGamer223

The input of the relay module is meant to get 0 or 3.3volt or 5volt (from an Arduino pin),
so connecting the input to 5volt or ground is ok.
Leo..
How do you mean 3.3V *or* 5V...

XGamer223

Okay I connected the relay with + and - and also connected - from the supply to the IN pin, works just like on an Arduino! thanks for helping me

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