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Topic: Futurlec Opto Relay with Arduino (Read 1 time) previous topic - next topic

retrolefty

Link to schematic broke?

Quote
If this is the case, what keeps the board from switching all the relays on if the arduino is off?


Powered off would mean the pin is not able to pass any current. Powered on, but outputting zero is capable of sinking current up to 20-30ma, so active low to turn on a relay is fine if the other side of the relay coil (or opto-isolator emitter) is wired to +5vdc.

Lefty


Terry King

OK Got the schematic....

This is simple active-LOW inputs with a 1K resistor so less than -5 ma from Arduino,but you have to set the output LOW to turn these on...

At Arduino startup the outputs are in high impedance and the OPto outputs will be off. 

Have to set an Arduino pin to OUTPUT and LOW to turn an OPto output ON.

Opto Outputs have an LED that will go on when output is active.

You need +12V and 12V common to output section, +5 and Gnd from Arduino to input section...

There is no "Serial Communication" involved...
Regards, Terry King  ..On the Red Sea at KAUST.edu.sa
terry@yourduino.com  LEARN! DO! (Arduino Boards, Sensors, Parts @ http://yourduino.com

FishArduino

So, when I want the relay to be "on" I use the digitalWrite(pinX, LOW) command?

Thanks for the help!

retrolefty


So, when I want the relay to be "on" I use the digitalWrite(pinX, LOW) command?

Thanks for the help!


Yes, and use the digitalWrite(pinX, HIGH) command to turn the relay off.

This of course assumes you have already used a pinMode command to make pinX an output pin.

Lefty

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