The problem is not the reduction in braking acceleration contribution to the sensor but rather the extent to which gravity affects the measurement. See Russell's excellent post. He points out that the timescale of braking compared with incline changes can likely allow proper discrimination of the two. Sean On Wed, Mar 27, 2013 at 8:44 AM, Carl Denk wrote: > Maybe I'm missing something here, but in normal roads, the slope of the > road surface (and vehicle) is not that great, with maybe 20 degrees > (36%)(tangent) being maximum. That would translate to an error of > 6%(cosine) in the acceleration. I would think that error due to nose > tilt up/down is negligible. :) Didn't try to work out the actual > geometry, but think this is rough indicator, the cosine represents the > difference in actual distance traveled vs. the horizontal distance, and > ignoring the centripetal acceleration when going around curves. > > On 3/27/13 7:19 AM, YES NOPE9 wrote: >> I want to build a device that flashes a rear brake light at an intensity= depending on the G-force due to braking. >> I want it to be super easy to install. Such as throwing it in the back = window and being done. This would possibly mean a battery and solar charge= r. >> >> #1 I do not want to use data from OBD2 ......... This would increase i= nstallation issues. >> #2 How might I differentiate between G-force due to braking and that du= e to the vehicle tilting nose up or nose down ? >> >> I was thinking maybe a gyroscope might do the trick. >> >> Gus > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .