15 cm of red wire which has been tinned at both ends
Soldering iron
Tin
Assembly
Locate the GPIO 3 (see the yellow circle in the photo).
Then locate prong # 33, circled in red. It is four prongs up from the bottom left-hand side of the GPIO 3.
Tin prong # 33 to ensure easy welding of the wire.
Weld the red wire onto prong # 33 of the GPIO-3 connector on the Olimex card.
Do not heat the prongs for too long during welding. Make sure the tin does not touch the adjacent prongs.