it requires for me to connect the grounds of the 3V battery (running the motor) and arduino (feeding the base of the transistor)... And there's voltage difference between two grounds.
So you're saying that my arduino shows the message "Serial port "COM4" already in use. Try quitting any programs that may be using it." for some other reason? Even though it happens only when I connect those two grounds?I just figured there must be some link to it...
Please enter a valid email to subscribe
We need to confirm your email address.
To complete the subscription, please click the link in the
email we just sent you.
Thank you for subscribing!
via Egeo 16