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Topic: GRBL + Relay issue. (Read 200 times) previous topic - next topic

eliseo88

Hello, I'm setting up a cnc machine and I want to use the spindle enable pin to turn on/of a 5V relay (picture attached.

I'm using GRBL 0.9j, which has a PWM feature on the Spindle enable pin...I downloaded a HEX file with the Variable_Spindle disabled so my GRBL shoud behave like previous versions (No PWM stuff activated...).

Now, if I connect a simple LED to the Pin 12, pretending it's my relay, everything works great, I power Arduino and the LED is down, and I can turn it on with M3 command and shut it back down with M5.

If I use a Relay, actually, always on Pin 12, as I power up Arduino it triggers the relay, so whatever is connected to the relay is On. Commands M3 and M5 are switched, M3 shuts it down and M5 triggers it.
I need the relay to be down when I turn on Arduino.

Any chance the relay board might be the problem?

Can you help me?


THANKS

GrooveFlotilla

Some people are like Slinkies.

Not really good for anything, but they bring a smile to your face when pushed down the stairs.

eliseo88

Uhm, can you help me with Resistance value? I simply have Arduino 5V and GND going to Relay + and - pins, and the Signal pin of the relay is connected to the Pin 12 of Arduino board.

THANKS.

GrooveFlotilla

Don't really know - try a 4k7.
Some people are like Slinkies.

Not really good for anything, but they bring a smile to your face when pushed down the stairs.

eliseo88

Solved.

Adding a Transistor seems to get it right. (I know it's redundant, but I need the Relay to handle a 24V valve, ain't got a mosfet or something else, so I'm sticking to the Transistor+Rely).

Sharing my set up for anyone having the same issue.

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