![]() Well, you have not provided any data, just an opinion. There is no defined maximum continuous current that the ESD protection network on the GPIO pins can sustain. I will remove the LED and bridge back the connection. If it receives more than 1V, it is high, if lower, then it is low. My Idea of Raspberry Pi GPIO is just like multimeter. ![]() I thought the two resistor is going back to the ground of the power supply? However with the LED fitted like this, the voltage readings on your voltmeter may be similar to what you can expect when you connect Pi. So the light would be very, very dim (you might see it in the dark). However the current flowing in the LED will be very small.Īssuming the yellow LED forward voltage is (say) 2V, the current will be (5V-2V)/20k = 0.15mA ![]() when the switch is closed the LED will be off, when the switch is open the LED may be on). from the left hand resistor down to 0V) which may simulate circuit operation (e.g. I suppose you could fit the LED in place of the gpio (i.e. The two 10k resistors don't have a path back to 0Volts, so there is no current flow, making all voltage readings wrong. You don't really have a circuit without the Pi connected. I am not that well versed in electronics, so does anyone have a pointer or idea of how to avoid this false edge in this case? I am guessing adding another capacitor somewhere is the solution, but where? The easy solution would be to just move the CAT-5 away from the powerline, but I'd like to solve it with electronics in case I encounter this problem again where I can not move the cables. If the switch is open (GPIO=1/high) a toggle of the lamps does not give a false edge. This only happens when the switch is closed. If I then toggle the power to the lamp - doesn't matter if it is on or off - a false edge appears. No more false edges.Īpart from a single issue: When the switch is closed the GPIO reads 0 (low) as it should. Introducing the two resisters and the capacitor as shown in the diagram above (idea from. This almost worked, but there was a lot of false edges - both rising and falling. Along the middle 3 meters of the CAT-5 runs a 220V DC powercable used for lamps.īefore the shown setup, I had tried connecting the switch directly to the GPIO and GND with no other components. The other 6 wires in the CAT-5 are not connected. They are 5 meters long, and is a single twisted pair of a CAT-5 cable. The two red parts are long wires to the switch. I am trying to interface with a simple switch placed several meters from my Raspberry.
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