I've got a single relay connected to my RPi but I can't seem to control it.
As you can see from the image above:
RPi -> Relay
5V -> VCC
Ground -> GND
GPIO4 -> IN1
Measuring voltage I can successfully verify that I can turn on/high off/low the GPIO pin (3.3V to 0V).
The problem is changing that state doesn't change the relay state. As soon as I set the pin's mode to OUT the relay lets the current go through.
Changing the pin's state through the Python API or through the console doesn't do anything, the current is always passing through. (Can turn it off by setting the pin's direction to IN..)
Also the wires connected to the relay are using NO (normally open) and COM.
Somewhere on the relay's product page it states: "Control signal TTL 3,5V-12V". Would this mean that the GPIOs output of 3.3V isn't enough to control the relay?