Relay turns on for a second when I plug it in

Hello!

I am making a solenoid door lock that opens up with a fingerprint sensor. So I control the solenoid with a relay module and I have connected it to the Normally Open pin so the relay stays disconnected and when a fingerprint is found then the relay turns on for 5 seconds and the solenoid unlocks. I power the arduino and the relay with 12V power adapter through the barrel jack. Basically everything works fine, however when I plug the power adapter in, the relay turns on for a second (meaning it unlocks the lock) and then turns off (it should stay turned off the whole until a fingerprint is detected).

How to make so the relay does not turn on for a second after powering it?

Thanks in advance!

P.S: Not sure if this is for Hardware or Software help flair.

Touch here for the full post on the Arduino Apprentices tumblr

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s