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I recently got this hat screen for my B+. It has headers to use the GPIO pins that aren't used for the screen. The screen works well, but I want to make use of the other GPIO pins. The only problem with it is I can't seem to find a ground that works. As you need a ground for pretty much anything, this is a pretty big set back. It does work if I touch the ground to an actual ground pin solder point, but this isn't really feasible with the screen on. Anyone have experience with this?

  • Just a question: what about vias with the numbers? Is there any with GND? – Boštjan Jerko Jun 5 '15 at 12:34
  • No, theres no ground or GND or anything like that. There's numbers, and also SDA, SCL, TX, RX, M0, M1, and CK. It's kind of possible to use the clock pin, but anytime something happens it would cause all the other pins to blink, which I would really like to avoid. – Aaron W. Jun 5 '15 at 13:05
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Two options:

  1. Instead of soldering on the supplied 2x20 female header, you get a stackable header like this one and solder this on. Now you have all 40 pins available, and you can pick your ground. Just make sure your other boards don't use any of the non-GND pins used by the display.
  2. If you don't mind soldering a wire on, you could solder a wire onto one of the GND pins exposed on the solder joints for the existing 2x20 header, and then use the exposed breakout of available pins for your other device, and the wire for ground. This would save you having to desolder the 2x20 header that came with the kit and you probably already soldered on.

Finally - the board seems to have 3 pins directly exposed (labeled #4, #5 and #6). Pin 6 on the Pi is GND - you could try to connect your ground there after first confirming with a multimeter that that pin is indeed ground.

  • That seems strange. A ground seems like a pretty big thing to leave out for giving access to GPIO. There's not much of anything that doesn't need any ground at all. I figured that I hadn't hooked something up properly, or was missing something obvious to not see one. – Aaron W. Jun 5 '15 at 13:29
  • Yes I agree with you - I don't understand AdaFruit's design here - I would have at least exposed one GND pin on that breakout header – Phil B. Jun 5 '15 at 13:30
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    Actually - I took a closer look and the breakout carries 3 pins labeled #4 #5 #6. If you look at the pinout of the rPi B+, you see that pin 4 is 5V, pin 5 is SCL1/GPIO3 (why didn't they label this as such?) and pin 6 is GND. You might want to check this with a voltmeter, but I assume that you can use this #6 as GND. Still -why they didn't label it as such I don't know frankly. Updated my answer above. – Phil B. Jun 5 '15 at 13:35
  • I think I have tried those pins, but I could have missed something. I'll give it another try when I get home and get back to you. Thanks for all your help! – Aaron W. Jun 5 '15 at 13:50
  • After a reply at the Adafruit forums it seems like a ground pin was just left out due to a design oversight. Kind of disappointing. That means the only options are to solder something into the header, or get a new header, which is going to be ugly either way. Crap – Aaron W. Jun 5 '15 at 18:58

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