No, it shouldn't, and if that's the way it is, you ought to be fine - however...TarjeiB wrote:Yes! That sounds similar to what I've seen some times - I was thinking I just didn't understand it.fruitloaf wrote:That's the board I have but I used a transistor to drive it as from my reading of the circuit it puts 5V into the GPIO line via the status LED. If you look VCC goes to R1 which goes via a diode and LED to the GPIO.
My reading of that (and I'm far from an electronics expert) is that when your GPIO is high the LED will be lit as you are still getting 5V - 3.3V into it and LEDs will show a usable amount of light down into low volt levels. When low you are sinking the 5V into GPIO. I think that the R1 resistor is what is limiting the current and stopping you from blowing up your Pi. I may of course be completely wrong about the above
I'm using a transistor and a couple of resistors to drive the input successfully.
However the GPIO is just GPIO -> R 1k -> Gate on the transistor and no other tracks on either side as far as I can see, does power really flow back through the gate of a transistor?
If you have wiringPi, then try this at the command-line:
gpio -g mode 23 in
gpio -g mode 23 up
gpio -g mode 23 down
assuming you're using GPIO pin 23.. (change for whatever)
See if it toggles the relay, alternating between up & down... that's enbling the internal pull-up, pull-down resistors...
Then try this:
gpio -g mode 23 out
gpio -g write 23 1 # Turn on
gpio -g write 23 0 # turn off
then try connecting a 330 ohm resistor from the gpio pin to 0v, however a "low" gpio pin really ought to turn off a transistor!