Part 2. Hardware Tweaks
Nintendo assumed you would always power your Wii Balance Board with four AA batteries and included no AC power adapter. Having only battery power would be inconvenient because we cannot permanently pair our Wii Board to our Pi through bluetooth. We need to sync it, then allow it to remain synced without draining the batteries so we can simply step on the scale and weigh. Luckily, there are several third-party adapters made for the Wii Balance Board that we can use to provide constant power from a wall outlet. Replace the batteries with a battery pack and plug the ac adapter into a wall outlet.
Having to pair the Wii Balance Board and Raspberry Pi every time we run our Python script presents another inconvenience due to the location of the sync button. The sync button is at the bottom of the Wii Board, which means we would have to flip it over every time we need to sync. We can fix this by making a little lever using a pencil and three 3/8" felt pads as shown above. The rechargeable battery pack exposes the sync button to the underneath surface of the Board. Tape a pencil (or something similar) that spans from the sync button to the outside front of the Board. Stack three 3/8" felt pads (or something similar) on the center of the pencil to create a stationary pivot. Be careful to not expose too much of the pencil out from the Board as you don't want someone to accidentally kick it out. Flip the Board over and you can press the sync button by simply pressing down on the lever. A bit of a hack but effective.
Depending on how you store your Wii Board, you may want to remove the rubber grip pads from the feet of the Board (the pads are simply stickers you can pry off). 3/8" felt pads can be placed on the Board's feet for easy sliding.