Pi Cobbler

[waltjos]

Are the pins on the Pi Cobbler isolated from eachother? I purchased the T-Pi Cobbler where common pins (gnd, 5v, some others), are connected together on the breakout board, but am interested in using the cable in a different project where I need all of the pins isolated.

[egutting]

If you look at this picture:
https://learn.adafruit.com/system/asset ... 1396764419

It seems that all the pins are isolated.

[waltjos]

I just wanted to make sure I wasent crazy! And I didnt catch that picture! good spot, thanks!

[gweas]

Here is what I noticed using the Pi Cobbler Breakout + Cable sold from adafruit. I've purchased multiples of these.

Using the grey 26 cable version. If the cable is bent, there is cross talk on the pins, certainly on pi BCM 8, or board pin 24. I haven't found out what other pins are affected but pin 24 is severely effected. 26 does not seem to be affected. Using certain usb micro cables to power the device you may see this more. A simple test using python to open the pin 24. Start up the program below to test the pins (you could test all pints and create a log what ones are affected maybe output to file). Once running, bend the cable. Try bending it all the way back. On mine I see high value. Most times even if slightly bent I see high value streaming down the terminal.

# code below is sample and may not be entirely accurate. With python don't forget to indent after try: while: if:, ..etc
##
python code:
import sys
import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
gpio_test_pin_24 = 8
GPIO.setup(gpio_test_pin_24,GPIO.IN)
current_state = 0
try:
#don't forget indents
print "press ctrl+c to exit"
while True :
#don't forget indents
current_state = GPIO.input(gpio_test_pin_24)
if current_state == 1:
#don't forget indents
print "high value on input pin detected!"

except KeyboardInterrupt:
#don't forget indents
print "quit"
GPIO.cleanup()

I've tested this with multiple devices, and multiple Cobbler Breakout + Cables even after returning one.

My worry is the cross talk or cable connects touch a 5v rail, which could damage raspi