Grbl + CNC Sheild + running LEDs

Hi all

Hoping I could get some help with my project.

I have build a cnc mill and am using an uno and a cnc shield v3.00, with grbl 1.1e.

I would like to add 12 or so indicator lights without adding/modifying grbl in any way.

What I wanted to do is add an led to the pin inbetween the arduino and the shield, so I know what the pin is doing with out looking back at the pc screen.

I did test just one LED from the spindle enable pin to ground and it did work at I wanted but did not try sending any g-code and test again.

I am learning about electrics but am unsure of what would happen to the hardware and the g-code with the added LEDs.

I have seen a video of someone putting indicator lights on the direction pin to the stepper driver and it lighting on a movement/hold of the motor.

This is ultimately the goal here. I just want clarification on the application I wanted

Thank you for reading this

You always need a current limiting resistor in series with such an LED. Try a few hundred ohms to 1k sort
of range.

Thanks for the reply MarkT.

I know about putting a resistor with the LED, what I wanted to know was what would happen to the pin with the LED attached. Would the pin pull more power or would the strength be shared?

Thanks again

pug1: Thanks for the reply MarkT.

I know about putting a resistor with the LED, what I wanted to know was what would happen to the pin with the LED attached. Would the pin pull more power or would the strength be shared?

Thanks again

Connecting a LED with a 220Ohm resistor to the Step/Dir/Enable pins on GRBL configured Arduino would do no harm nor affect the code. Only when that pin is ON will the LED illuminate, the voltage will also be sent to the driver board which will move the motors. The input impedance of the drive boards is high so there will be enough power available at the pin for both things to work.

aqibi2000: Connecting a LED with a 220Ohm resistor to the Step/Dir/Enable pins on GRBL configured Arduino would do no harm nor affect the code. Only when that pin is ON will the LED illuminate, the voltage will also be sent to the driver board which will move the motors. The input impedance of the drive boards is high so there will be enough power available at the pin for both things to work.

This is exactly what I needed. Thank you so much for you reply. I love arduino lol

Again thanks to you both

pug1: Thanks for the reply MarkT.

I know about putting a resistor with the LED, what I wanted to know was what would happen to the pin with the LED attached. Would the pin pull more power or would the strength be shared?

Thanks again

So long as you limit the current to below the pins maximum it will work, in practice upto 20mA to the LED would be no problem, but many LEDs are bright enough at less.