arduino relay 2 channel relay module in 1 digital input question

Hi all, i have an arduino and arduino relay modul and i would like to force chanel 1 (digital input 1) to force it so that the channel 1 is active so that as soon as power is provided it activates with no input needed from say an arduino etc, i am wiring up an access control and it has a relay output (2 pins) which is powered up when the correct key is swiped across its rfid range so i want to use this (around 4 volts output) to power the relay so that it can act as a switch that allows the higher voltage circuit to open a electric lock, so i need to either put in1 to ground or is it wire it to the positive (same as the power circuit across this in 1 to activate the relay? is this correct if not how can it be done so i do not need to make it more complicated then needs be? please someone reply and say its ok to bypass the in1 (short it to ground or vcc to activate)? i hope this makes sense and i want to keep power consumption to a minimum so other electronics maybe not a good idea as i wish to run all these from 9 volt batteries (1 for the access control unit and 2 9v batts for the door unlock mechanism (as 9 wasn’t enough)).

Hello and welcome :slight_smile:

Most relay modules can be used in two modes: either Normally Open (NO) or Normally Closed (NC). In your case you want to use NC for the relay 1, so that it is closed without the need of any energy from your batteries.

Hello, is this possible to let the relays work in different times? I mean relay1 is on for 5 minutes after that relay1 goes low and relay2 works for 3 minutes.

I have tested this with two LED it works fine but when i connect the 2-channel relay Board it work not if i want.

Any ideas?

Show which relay you have. Show your code. Explain what you want, preferably organized into paragraphs. Show how you're powering everything.