Use your iPod for a dynomometer! - Kawasaki Forums


Off Topic A place to boldly go off topic. just about anything goes.

Reply
 
 
 
Thread Tools Search this Thread
  #1  
Old 08-15-2008, 12:22 AM
Worlok14's Avatar
Senior Member
1st Gear Member
Thread Starter
 
Join Date: Feb 2008
Location: Indianapolis and Toledo
Posts: 5,599
Default Use your iPod for a dynomometer!

Do you want your own private Dyno???

Now you can download a software and install it on your iPod touch or iPhone, if you fix the iPod/Phone on the car or bike the software will use the accelerometer that your device has in it to calculate intereting numbers... Some guys I know have done this already with their cars and even thou the numbers are not exact, they come pretty close to what you get in a Dyno...

Now before you call bullcrap, read this:

An accelerometer measures the acceleration and gravity it experiences. Both are typically expressed in SI units meters/second2 (m/s2) or popularly in terms of g-force.

The effects of gravity and acceleration are indistinguishable, following Einstein's equivalence principle. As a consequence, the output of an accelerometer has an offset due to local gravity. This means that, perhaps counter-intuitively, an accelerometer at rest on the earth's surface will actually indicate 1 g along the vertical axis. To obtain the acceleration due to motion alone, this offset must be subtracted. Along all horizontal directions, the device yields acceleration directly. Conversely, the device's output will be zero during free fall, where the acceleration exactly follows gravity. This includes use in an earth orbiting spaceship, but not a (non-free) fall with air resistance, where drag forces reduce the acceleration until terminal velocity is reached, at which point the device would once again indicate the 1 g vertical offset.

For the practical purpose of finding the acceleration of objects with respect to the earth, such as for use in an inertial navigation system, the correction due to gravity along the vertical axis is usually made automatically, e.g. by calibrating the device at rest.

Now the iPhone/iPod has a built-in accelerometer in order to detect in which position the device is being held (horizontal-vertical), this accelerometer is used by the device to calculate movement. This accelerometers are a copy of our internal hearing system (the one which is responsible for balance), and it was commercially used first in the segway vehicles... http://www.segway.com/

Beleive it or dont!
Reply With Quote
  #2  
Old 08-15-2008, 01:31 AM
whitehendrix's Avatar
Senior Member
1st Gear Member
 
Join Date: Dec 2007
Location: terrorizing southeastern norf carolina
Posts: 2,092
Default

i've actually heard of this already.
now, whether calibration and all is a concern, i'm not sure, as i'm not an accelleromoter engineer..lol


theres certain types of them, tho.. i know certain alarm shock detectors typically rely on a type of accellerometer in a way.

a basic type is a spiral spring mounted vertically on the circuit board. in dead center, not touching the spring, is a rod. when substantial force is exerted radially, the spring flexes over and touches the rod in the middle.

theres a certain amount of force is needed to make that happen, obviously.. but, this is pretty much a switch. not a sensor.

thers other types, and while i won't bore you with details on THEIR functions, i'd just be willing to bet that they're all not exactly suited for detecting forces and/or acceleration..

i dunno.. my .002 but i definitely have heard the iphone accellerometer trick.
Reply With Quote
  #3  
Old 08-15-2008, 02:26 AM
Nobrakes's Avatar
Admin
1st Gear Member
 
Join Date: Jan 2006
Posts: 7,269
Default

I believe the iPhone uses a MEMS type accelerometer. There are several types of these, the simplest just detects the change of a small mass from a neutral position. Another type of MEMS device detects the deflection of a small bubble of heated air using a tiny thermocouple. I've used several types they all work very well.

For example, see the analog devices adxl202. I think the one in the iPhone might be made by ST Microelectronics, though, namely the LIS302 which is a 3-axis sensor.

I just got an iPhone so I may have to download this program and try it out. It probably works pretty well for a ballpark figure, but I'm not sure I'd base any truly important decisions on the result.
Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
listening to your ipod while u ride... nin.zx.6r Ninja ZX-6R & ZX-6RR 26 10-15-2007 05:41 PM
iPod Nano (Multi-Color) Desouza Off Topic 9 03-08-2007 05:13 AM
Free iPod Nano2 storki PRIVATE For Sale / Trade Classifieds 3 07-20-2006 04:31 PM
Some IPod Help Mounting. BigRig18Wheeler Off Topic 43 07-20-2006 05:05 AM


Tags
equivalence, freefall, ipod, lis302, principle, programming

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Advertising
Featured Sponsors
Vendor Directory

All times are GMT. The time now is 09:09 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.