I am not sure this is the right place to post.
I am an Arduino Uno user, and I have a problem in a relay module (SainSmart 2-Channel 5V Relay Module for Arduino). I wish you guys to help me.
In specific, I connected a Arduino Uno with a relay module in order to control (i.e. open and close) a solenoid valve. That is, at a certain period, the Arduino Uno delivers a signal to the relay module through the IN1 pin, finally controlling the solenoid valve. However, whenever the relay module controls the solenoid, it makes a noisy sound like “tic toc” while flickering one time. (I want to eliminate the noise).
For your information, I attached a link which includes a video:
In the video, you can easily see the noise at around 00:00:16 and 00:00:36.
Could you please help me solve this problem? Any advice would be really appreciated.