accelerometer

I know this question is definitely solved somewhere many times already, please enlighten me if you know of their existence, thanks. Quick rundown: I want to compute from a 3 axis accelerometer the gravity component on each of these 3 axes. I have used 2 axes free body diagrams to work out the accelerometer's gravity component in the world X-Z, Y-Z and X-Y axes. But the solution seems slightly off, it's acceptable for extreme cases when only 1 accelerometer axis is exposed to gravity, but for a pitch and roll of both 45 degrees, the combined total magnitude is greater than gravity (obtained by

I am designing a robot, and need to track the distance and direction of the robot motion, Nothing in 3D, I only need x,y and angle in x y plane. My question : Is it possible to use gyro and accelerometer with kalman filtering or any other methods to track this? (I do not have motor encoders) My constraints : I do not have space to include a gps (due to power requirements) or motor encoders (due to motor support) Ali No, not really. If you integrate the accelerometer values twice you get position but the error is horrible. It is useless in practice. Here is an explanation why (Google Tech Talk)

I am creating a tuning fork app, where you pat the iPhone into the palm of your other hand, or against a soft surface in order to set the fork zinging. So I would like to detect the energy contained in each 'bump' (EDIT: Removed a ton of gumpf) Can anyone help me crack this one? Thanks to one of the wizards on freenode's #math channel (thanks Igor), I have a really good working solution. You use the standard method to fire a callback at the maximum frequency possible (100Hz), which will contain the instantaneous acceleration x,y,z values. I will let the code speak for itself, good code should

i want to know how to calculate steps taken using the Accelerometer. Actually i calculate acceleration and use this code to count step length = sqrt(x * x + y * y + z * z); if(length>=2){ stepcount+=1; } where length calculate acceleration using acceleration.x, acceleration.y,acceleration.z But my main problem at starting the application the stepcount gives correct step value but as time pass its value is not correct.Plz help me Basically you're using sudden acceleration over a certain value as a sign that someone is ending or starting a step. First, you have to make sure you end up sampling

How to measure time the vehicle takes to accelerate from 0 to 100 km/h (0-60 mph) in 400meters (a quarter mile) using iPhone accelerometer? I have situation where i need to calculate the time the vehicle takes to accelerate from 0 to 100km/h in a 400 meters(quarter mile),i need to implement this using iPhone accelerometer. You can use the acceleration values from the accelerometer to measure the velocity. There is really good paper ( Implementing Positioning Algorithms Using Accelerometers ) which explains the errors you get from the accelerometer and the techniques to get the velocity and

Given an Accelerometer with 9 DOF (Accelerometer, Gyroscope and Magnetometer) I want to remove/compensate the effect of the gravity in accelerometer reading (Accelerometer can rotate freely). The sensor gives the orientation in quaternion representation relative to a (magnetic)north, west and up reference frame. I found this http://www.varesano.net/blog/fabio/simple-gravity-compensation-9-dom-imus but couldn't understand the basis for the given equation. How could I achieve this given above information? You need to rotate the accelerometer reading by the quaternion into the Earth frame of

I want to know current speed of car and make a passed path. I have an Android phone with accelerometer and gyroscope which sent me data. This is the data in phone system of coordinate that probably wouldn't the same as coordiante system of car. How I can transform this accelerations and rotations to car system of coordinate? The generic answer for your generic question is no . The acceleration measures the changes in the speed, so the best you could get from acceleration, is the speed variation. To get the absolute speed you would have to have the initial speed and add it to the speed change:

In my cocos2d game, I have my player sprite and I want to have him move in the direction I tilt my iPhone. I can deal with that, the hardest bit which I can't work out is: How do I make my sprite rotate to point in the direction I am tilting? This is represented very well in the 'Tilt to Live' game on the app store. I want controls just like that. My sprite(for those unfamiliar with cocos2d) does have a rotation value if that helps. Thanks. Fattie If you don't like the above, here's a simpler way to get a reasonable result! Hold the iPad in front of you, let LR be the left / right tilt, TA the

I want to filter the accelerometer values using a moving average, how is this done? Thanks A simple, single pole, low pass, recursive IIR filter is quick and easy to implement, e.g. xf = k * xf + (1.0 - k) * x; yf = k * yf + (1.0 - k) * y; where x, y are the raw (unfiltered) X/Y accelerometer signals, xf, yf are the filtered output signals, and k determines the time constant of the filters (typically a value between 0.9 and 0.9999..., where a bigger k means a longer time constant). You can determine k empirically, or if you know your required cut-off frequency, Fc , then you can use the