Here are some pictures of how I keep constant power to my wiimote. I never have to change the batteries and this lets me not have to re-sync my controller and computer as long as I leave both on all the time. Buy an AC to DC converter like
this one, and use aluminum foil to keep the 9 volt contacts end pressed into the controller. Notice on the left picture that I had to put a small piece of tin foil on the wiimote's right contact before I put the 9 volt piece in. This helped the two maintain better contact.
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