| The 'Wii Nunchuck' from 'Nintendo' is an extension | | | | company. |
| controller for the 'Wii Remote'. The 'Wii Nunchuck' | | | | Features of the accelerometer are:- |
| connects to the 'Wii Remote' via a 6-pin expansion | | | | - 2.4V to 3.6V single supply operation |
| port. For the purpose of most robotic projects | | | | - Low power consumption |
| (accelerometer based controller), only the 'Wii | | | | - +-2g full-scale |
| Nunchuck' is used. | | | | - 0.5mg resolution over 100hz bandwidth |
| The 'Nunchuck' is identified by the 16-bit constant | | | | - Embedded self test |
| 0x0000 (0xFEFE encrypted) at register address | | | | - Output voltage, offset and sensitivity ratio metric to |
| 0xa400fe. It provides three-axis acceleration data, two | | | | the supply voltage |
| digital buttons, and an X-Y analogue stick. For this | | | | - High shock survivability |
| project, two-axis acceleration and X-Y analogue stick | | | | The accelerometer measures the force exerted by a |
| data are used. | | | | set of small proof masses. Therefore, it measures |
| The 'Nunchuck' reports its information as 6 bytes of | | | | linear acceleration in a free fall frame of reference. If |
| data, readable at 0xa40008 and able to be streamed | | | | the 'Wii Nunchuck' is in free fall, it will report zero |
| using Data Reporting Modes that include Extension | | | | acceleration. At rest, it will report an upward |
| bytes (unused bytes are filled with 0x00). Peripheral | | | | acceleration (+Z, when horizontal) equal to the |
| Protocol is 400kHz "fast" I2C, with slave address 0x52. | | | | acceleration due to gravity, g (approximately 9.8 m |
| Decryption is by using the formula: | | | | s²) but in the opposite direction. This knowledge is |
| 'x = (x ^ 0x17) + 0x17' | | | | applied to derive tilt (value used in interfacing codes) |
| Where ID of 0x17 is Read Memory and Registers | | | | from the acceleration outputs when the 'Wii Nunchuck' |
| Inside the 'Wii Nunchuck', there is a three-axis linear | | | | is reasonably still. |
| accelerometer, 'LIS3L02AL' from 'STMicroelectronics' | | | | |