## Re: [Gumstix-users] use of an accelerometer.

 Re: [Gumstix-users] use of an accelerometer. From: Jeff Sadowski - 2007-07-23 20:56:03 ```ooh you could also have it deploy a parachute :-P On 7/23/07, 4837jw@... <4837jw@...> wrote: > A really cool application for the accelerometer is relative position > calculation. Combine this with the GPS and you can achieve relatively > high resolution position data. > > The potential robotics appications are tasty. > > See the datasheet link at the bottom of this page: > http://docwiki.gumstix.org/Frequently_asked_questions/Goliath_boards > > James > > > > > On Jul 23, 2007, at 1:06 PM, Black, Michael wrote: > > > >> Actually an accelerometer will show 1G at rest and 0G during free- > >> fall. > >> Just one change occurs from rest to free-fall (i.e. 1G...0G). > >> And you need to be sure that you have the vertical axis being measured > >> -- otherwise you need a 2 or 3 axis accelerometer. > > > > This is a 3-axis accelerometer. > > > >> You're not actually accelerating during free-fall (your > >> acceleration is > >> constant) -- but your velocity is increasing. > >> Here's some good info on the math... > >> http://www2.usfirst.org/2005comp/Manuals/Acceler1.pdf > > > > You are actually accelerating during free-fall, at a constant 9.8m/ > > s^2. Your velocity cannot change unless you're accelerating. The > > accelerometer is not really measuring your acceleration, it's > > measuring strain on a MEMS crystal; when you're at rest, the crystal > > is being tugged on by gravity, but the table or whatever you're > > sitting on is countering that force, and thereby creates strain in > > the crystal. When you're in free-fall, you're accelerating at the > > same speed as the crystal, so there's no strain in the crystal, and > > so it measures 0. > > > > C > > > > ------------------------------------------------------------------------- > > This SF.net email is sponsored by: Splunk Inc. > > Still grepping through log files to find problems? Stop. > > Now Search log events and configuration files using AJAX and a browser. > > Download your FREE copy of Splunk now >> http://get.splunk.com/ > > _______________________________________________ > > gumstix-users mailing list > > gumstix-users@... > > https://lists.sourceforge.net/lists/listinfo/gumstix-users > > > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > gumstix-users mailing list > gumstix-users@... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > ```