Resistor between 5V PIR and Raspberry Pi GPIO pin


#1

I am attempting to connect a PIR sensor to a GPIO pin of my Raspberry Pi. In the instructions in the Cayenne
documentation indicating how to wire up the sensor, the output of the PIR (max 5V) has a current limiting resistor between the output and the GPIO pin. Unfortunately the instructions do not specify the value of the resistor. Does anybody have an idea of what a reasonable value for the resistor should be ?

Thanks

Jerry


#2

Sorry for the late reply. You don’t need a current limiting resistor as all the common PIR’s output 3.3v, unless you are using one that doesn’t look like this https://maker.pro/storage/xO4cooX/xO4cooX8woFXbeNrsRGK4U0cBbvLJgZxKWwrJrOX.jpeg If you are worried about it, throw a multimeter on the data pin and check what the voltage is.


#3

Adam:

I reviewd the PIR I’m using and as you said the output voltage is 3.4 V

Thanks

Jerry H