Sending output signal to input on another arduino, temperature

Using Arduino Project Guidance
#1

Hello

I currently have a setup where I measure temps, displaying to two 7 segment displays using ds18b20 sensors on the 1st arduino.

This is used to manually (at present) set commands away using push buttons on another arduino.

I cant use one arduino due to physical limitations in the setup.

Ideally, at a certain point I would like the 2nd arduino to set away its tasks when it receives a signal at a certain temp from the first one.

Am I right in thinking I need to do the following?

On the temp (1st arduino), I need to do an IF statement to send an Output high to a pin once a certain temp or above is reached?

Then

On the second machine, set the IF statement to wait until it receives the high signal to a local input pin?

Its a very simple 2nd arduino with delays etc and no millis as the procedure it carries out is very linear in scope.

Would I have to do Input Pullup? And would I need to do anything to prevent the pins activating accidently on power up?

#2

Do you want to send from Arduino #1 only once or continuously when an over-temperature occurs?

What communication hardware are you planning on using?

#3

I just intended to send it continously in a loop

No communication setup at all, I dont need the 2nd arduino to know the actual temp, just proceed down the program when i detects a high signal from a pin, generated by the other arduino

#4

Oh that's easy, you just monitor a pin for a "high" or a change in condition on the second one.

#5

fall-apart-dave:
Oh that's easy, you just monitor a pin for a "high" or a change in condition on the second one.

Cheers for the reassurance. I just thought it would be too good to be true!

#6

Don’t forget to connect the grounds.

#7