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I have connected 3 different official nunchucks to my raspberry the following way; pin 1: 3.3v, pin 3: SDA, pin 5: SLC, pin 6: GND

I tried several power supplies including a 230 watt pc psu but every time my raspberry wont boot or shutsdown after connecting a nunchuck.

Any ideas on what the problem could be?

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    Power the nunchucks separately from the power supply and only connect SDA/SLC pins. Use the same power supply for both Pi and nunchuks to ensure the common GND though- use the big one you got.
    – Piotr Kula
    Nov 5, 2013 at 16:37
  • I tried this, did not work. When I measure the current before connecting its 5.1V and after it drops to 2.8V.
    – thommie
    Nov 5, 2013 at 18:50
  • Where are you measuring the current? Can you post a photo of all the connections.
    – Piotr Kula
    Nov 5, 2013 at 19:04
  • connected it like this, circles is where I measured. i40.tinypic.com/2hfrzts.png I hope its clear enough
    – thommie
    Nov 5, 2013 at 19:29
  • Do you still have the VCC connected to the power supply AND nunchucks? You are connecting to the GPIO pins right?
    – Piotr Kula
    Nov 5, 2013 at 19:49

1 Answer 1

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So I just went and searched for Wii Nunchuck pinout and it seems like your PINS are not connected as in your diagram. It is possible that you numbered your pins in another order but you should cross check.

Source

enter image description here

What the guy explains is that you can connect +3.3v to PIN 2 or 3 it does not matter because internally they are connected. This is a sensing PIN for the Wii. Pin 1 is SDA and PIN4 SCL

Another thing is that the Pi runs at 5Volts and this WiiChuck at 3.3Volts. (But I think some other ones run at 5Volt - I saw some a few with 5V markings)

Any way even if you are powering the Pi on the GPIO 5v pin and then the Nunchuck on the GPIO 3v3 you might have a power limitation problem on the 3v3 rail. A computer PSU will have 3v3 on the Orange cable and 5v0 on the Red cable. Keep yellow 12v0 away form the Pi. Connect the GND direct to the PSU as GND over current can also cause issues.

Double check you do not have a short somewhere or that the pins are mixed up.

enter image description here

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  • Sorry I forgot to mention I'm using an adapter like this one seeedstudio.com/depot/grove-nunchuck-p-1474.html
    – thommie
    Nov 5, 2013 at 21:47
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    ONe thing that is got me consufused is that it says 5volts but the Wii nunchuck pinout shows 3v3? Are there various versions. Sorry I never owned one of these.
    – Piotr Kula
    Nov 5, 2013 at 21:50
  • Wii nunchuck suppose to be connected to 3v3 busses but it is possible to run them on 5v. I tried your way, the raspberry does not shutdown but the nunchuck isn't detected either...
    – thommie
    Nov 5, 2013 at 22:21
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    Yes of course! Tried it again to be sure.
    – thommie
    Nov 6, 2013 at 10:32
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    Sorry - I had to ask. This is a really strange problem. I am unsure of what to suggest. Could you possibly take a real life photo of the whole setup? I can suggest to disconnect everything and connect one wire by one. Starting from GND, then Vcc , then the I2C. Monitor when the voltage drops. When it drops measure the Ohms between the two pins. Mostl likely Vcc and GND. Measure the Ohm.
    – Piotr Kula
    Nov 6, 2013 at 10:42

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