On 21/01/18 19:36, Gordon Henderson wrote:
> In article , RobH  
wrote:
>> I have been trying to get a simple led project to work on my pi 3 using
>> a 5 volt 6 amp power supply and a 510 ohm resistor in front of the led
>> to reduce the current going to it. Now after trying different tutorials,
>> my pi 3 goes off on it's own from being powered up.
>>
>> If I remove the power lead and restart the pi 3 the red comes on and the
>> green led flashes as well as the ethernet port flashing green led.
>>
>> I ssh into the pi 3 to try and run a python program, but then the pi
>> dies, and there are no lit up leds anywhere at all on it.
>>
>> Is there any way it can be fixed or should I just forget about it.
>
> Remove all LEDs, buttons, etc.
>
> Boot the Pi, login, run a few programs - just to make sure the Pi
> itself is running OK.
>
> Halt and power down.
>
> Connect from GPIO pin 11 (physical pin 11) to the LED to a resistor then
> to 0v.
>
> Boot Pi & login:
>
> Run this command in a terminal
>
>    gpio -1 mode 11 out
>    gpio -1 toggle 11
>
> Run the last command a few times. LED ought to go on/off.
>
> Your 510 ohm resistor ought to be fine - as a general guide
> for most generic red/yellow/green LEDs you can use a value of
> Voltage * 100 ohms, so for the 3.3v Pi, then 330 ohms is fine.
>
> More pictures here which might help you get started:
>
>    https://projects.drogon.net/raspberry-pi/gpio-examples/blink/
>
> Gordon
>

I have ran the commands you asked me to and they did nothing to make the
led come on or off.

I did some checking of some of the GPIO pins and found this :

GPIO 17 0.06 vdc
GPIO 27 0.01 vdc
GPIO 22 0.07 vdc
GPIO 23 0.05 vdc
GPIO 24 0.02 vdc
GPIO 08 3.25 vdc
GPIO 07 3.25 vdc
GPIO 25 0.01 vdc

If GPIO 17 or physical pin 11 is only showing 0.06 Volts, then the led
will never light up.

Thanks for the link and I also tried the commands from that page , to no
avail.

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