Angle sensor development

[Sri10]

Hello,

     I want to build a angle sensor with the following brief spec.:

Range : +/- 30 deg

Accuracy : 0.1 deg

Resolution : 0.01 deg

The angle measured will be roll or pitch(one at a time) of a body. Would like to have some advise from the community.

Looking for an interesting discussion

[Martin35804]

Hi,

Start by reviewing following app. note AN3107 Measuring Tilt with Low-g Accelerometers

http://cache.freescale.com/files/sensors/doc/app_note/AN3107.pdf?&Parent_nodeId=&Parent_pageType=

page 4:

...A 12-bit ADC cuts 3.3V supply into 4095 steps of 0.8mV for each step. Therefore, by taking one ADC reading of the MMA6260Q again at 0g (0° of tilt for an x-axis device), would now result in the following:

0°: 1650mV + 0.8mV = 1650.8mV

90°: 2450mV + 0.8mV = 2450.8mV

This results in a 0.057 degree resolution at the highest sensitivity point (0°) and 1.63 degree resolution at the lowest sensitivity point (90°). However, for 0.8mV changes, the noise factor becomes the factor to consider during design. How much noise the system has will depend on how much resolution you can get with a higher bit count.

The 14-bit ADC accelerometer can be proportional better.