Dual Offset Extension

Posted in Scope Mounts | Scope Accessories by admin on March 21, 2009 No Comments yet


Featured Dual Offset Extension For Sale:



The 'Wii Nunchuck' from 'Nintendo' is an extension controller for the 'Wii Remote'. The 'Wii Nunchuck' connects to the 'Wii Remote' via a 6-pin expansion port. For the purpose of most robotic projects (accelerometer based controller), only the 'Wii Nunchuck' is used.

The 'Nunchuck' is identified by the 16-bit constant 0x0000 (0xFEFE encrypted) at register address 0xa400fe. It provides three-axis acceleration data, two digital buttons, and an X-Y analogue stick. For this project, two-axis acceleration and X-Y analogue stick data are used.

The 'Nunchuck' reports its information as 6 bytes of data, readable at 0xa40008 and able to be streamed using Data Reporting Modes that include Extension bytes (unused bytes are filled with 0x00). Peripheral Protocol is 400kHz "fast" I2C, with slave address 0x52. Decryption is by using the formula:

'x = (x ^ 0x17) + 0x17'

Where ID of 0x17 is Read Memory and Registers

Inside the 'Wii Nunchuck', there is a three-axis linear accelerometer, 'LIS3L02AL' from 'STMicroelectronics' company.

Features of the accelerometer are:-

- 2.4V to 3.6V single supply operation

- Low power consumption

- +-2g full-scale

- 0.5mg resolution over 100hz bandwidth

- Embedded self test

- Output voltage, offset and sensitivity ratio metric to the supply voltage

- High shock survivability

The accelerometer measures the force exerted by a set of small proof masses. Therefore, it measures linear acceleration in a free fall frame of reference. If the 'Wii Nunchuck' is in free fall, it will report zero acceleration. At rest, it will report an upward acceleration (+Z, when horizontal) equal to the acceleration due to gravity, g (approximately 9.8 m/s²) but in the opposite direction. This knowledge is applied to derive tilt (value used in interfacing codes) from the acceleration outputs when the 'Wii Nunchuck' is reasonably still.

Calfred writes on various topics and provides useful tips about their relevant topics. You can also find him where he has a website which helps people find a zero gravity chair and back massage chair. Never ever sit on another generic common chair anymore. Find out why at the website.

Leave a Comment