watching for a trigger from another device on mega

Projects Programming
1

hi i am still new to all this arduino coding and just want to make sure i don't cause any damage to my mega board by connecting it up wrong

i have an RF device which watches for a signal from the transmitter.
once it receives the signal it will pulse 3V to one of its recving pins

i would like to detect when it turns the pin from GND to 3v

the image above shows the reciver board.
the pin marked is either high or low

i need to detect whether it high or low
if it's high i want to run a function if it low just ignore

whats the best way to connect this to the mega board
and what code can i use to detect in the main loop
thanks in advance for any replys

2

If you are sure that the voltage on the pin will never ever exceed 5v you can connect it directly to an Arduino I/O pin and also (of course) connect the GND to the Arduino GND.

Although the Mega works with 5v it should correctly detect 3v as HIGH.

How long does the pulse last ?

If it is very short-lived you will probably need to use an interrupt to detect - read about attachInterrupt().

If the pulse stays high for a few millisecs you will probably be able to detect it by polling the relevant I/O pin.

...R

3

its 3 or 4 short bursts of data
the voltage is 1.8—3.6V working voltage
and the trigger will stay at high as long as the transmit button is pressed

so im going to put it into the main loop on a poll as the board isn't doing that much else

so its ok to do a if such a pin is high etc

on one of the digital pins then safely?

4

so its ok to do a if such a pin is high etc

on one of the digital pins then safely?

Yes, just be sure to read the pin with the yellow wire connected to it. Oh, wait, that's all of them. Why?

5

PaulS:
Yes, just be sure to read the pin with the yellow wire connected to it. Oh, wait, that's all of them. Why?

Time for bed, Paul.

...R

6

because i only need to read one pin. ???

7

because i only need to read one pin

That would be the one with the yellow wire connected to it, right?

8

3.3V should reliably read as HIGH, 3.0V is borderline (in practice you are likely to get away with it,
but this is luck, not design)

9

yes paul pin No 3 not that it makes a difference to the question

thanks everyone. it works a treat