I'm wanting to figure out if a user is not moving at all, walking, or running using the iPhone. I'm not trying to implement a pedometer. I just want to know around about if someone is moving briskly, slowly, or not at all. I don't need mph or anything like that.
I think the accelerometer may be able to do this for me, but I was wondering if someone knows of any tutorials or example code that might be able to point me in the right direction?
Thanks to all that reply
The accelerometer won't do you any good here - it will only capture changes in velocity.
Just track the current location periodically and calculate the speed.
There are no hard thresholds for walking vs. running motion, so you will have to experiment a bit. The AccelerometerGraph sample code should get you started on how to get and interpret accelerometer data.
The Accelerometer is good, but if the user has an iPhone 4 or iPad 2 you should use the gyroscope.
CMMotionManager and Event Handeling Guide - Motion Events
Apple Documentation is the best example you can get!
People have a different bounce in their step between walking and running which can be measured with the accelerometer, but this differs between individuals (what shoes they are wearing, what surface they are upon, what part of the body is attached to the iPhone etc.), and this motion can probably be imitated by shaking the iPhone just right while standing still.
Experiment by recording the two types of acceleration profiles, and then use some sort of pattern matching to pick the most likely profile candidate from the current recorded acceleration data.
Related
I have a GPS app that I would like to detect if the user is standing still and not moving. Using Core Location works for this, but is sometimes not accurate because new updates move and gives the illusion of speed and motion.
So, I am wondering if in addition to that, I can also use Core Motion. Is this a good idea to detect motion such as someone walking, running, driving, etc, and know when they are no longer doing that motion? Or, is Core Motion only for small movements such as tilting the device or lifting it to your ear?
I wanted to tell others who visit this question what I've learned and what I think about this approach.
I have been doing some research of my own to know whether this is possible, and more importantly, even if it is what is the battery consumption and accuracy of the location change detected. For Android though, this question was asked quite sometime back. The answer provides links to this Google Tech Talk. At 23:20, the speaker talks about how difficult it is to achieve this and the accuracy you will achieve in the results.
Even though I have to come to realize the battery consumption from sensors on the iPhone is a little lesser than in most Android phones, I still think this is a costly affair in terms of accuracy and battery consumption.
you can use the GPS with the sensor readings to distinguish between walking, running, etc. if you combine the tilt angle frequency change and the GPS speed information (you need to do some work to get some of this info of course, but thats the way to do it).
You are talking about 4 different measurements from 4 different sensors (technically more than 4 but..) -
Latitude & Longitude - from CoreLocation. It uses a mix of GPS + cell tower triangulation.
Accelerometer - the current orientation of the device in 3D space.
Gyroscope - orientation of the device on its own axis.
Magnetometer - which tells you which direction a device is point w.r.t south,north,east,west
Of all these I think only Latitude & Longitude are of use to you. Basically what you do is to make the sensitivity (i.e. the update rate from the sensor) a bit more relaxed. With some tweaking around with this you should be able to tell with good accuracy if a person is standing or moving.
I'm using the accelerometer to move an object on my screen.
It's only working when the iphone is flat.
If I use the iPhone in another position, the object is not moving like I want
(the Y axis is not well managed).
So, I've to calibrate the position of the accelerometer, I guess.
But I've no idea how to do this.
Please help me.
Thanks in advance.
Regards,
ALpesH
hi hope all is well.
A simple google search came up with this beautiful post.
It is exactly what you wanted. A tutorial on Accelerometer Calibration & Optimizations.
This tutorial assumes you know the basics of the accelerometer. If not there are plenty of tutorials on google that will help get you accustomed to the accelerometer basics.
This tutorial will focus on 3 things:
Calibrating the accelerometer so the user can play your game from any
position.
Changing the "sensitivity" of your object's movement.
Adding the option to "invert" the controls.
First off, why bother adding these features? Simple. Launch your accelerometer based game and try the following tests:
Play sitting up in perfect position.
List item
Play it slouched over.
Play it lying down on your side.
Play it lying on your back with the device parallel to the floor and
the screen facing you.
Obtained from this website:
http://www.iphonedevsdk.com/forum/iphone-sdk-tutorials/39833-tutorial-accelerometer-calibration-optimizations.html
Let me know if this helps if it does choose this as the answer.
Other than that if you need any more help let me know
Ive implemented this tutorial code in my own app and i am not playing a simple ping pong game upside down and also playing it on the side whilst lying on the bed. :D
Pk
I am hoping to build an application similar to those egg shaking applications, to better understand how to detect motion on the iphone. I've been looking at accelerometer methods and motion and motion methods, but can't seem to get working what I want to do.
The specifics of my need are as follows: I want to be able to play one sound when user shakes the phone away from them, and play another sound when they shake back towards them. The motion from the user would be very similar to an egg shaker, with two different sounds able to be played depending on whether they moved the device towards or away from their chest. It would also be good to measure the intensity with which they moved away or towards.
Any ideas?
I've searched apple's sample code for a similar application, but there doesnt seem to be one.
Look at this game which is open source and makes great use of the accelerometer. It's a good one to be able to tell which direction you are going, but I haven't messed around much with intensity. I'm sure it's easy enough once you get into the details.
http://github.com/haqu/tweejump
I'm creating an iPhone application.
My application needs to detect the movements of the accelerometer and report the case of movement by the user.
In practice I have to constantly check that the coordinates received from accelerometer are equal to the coordinates saved in my movement.
My problem is that its implementation is not simple because I know there are many factors that create difficulties.
Someone knows a tutorial or guide to propose.
I also welcome suggestions ...
Thank you very much
You can use this paper as a starting point.
It shows detection of a user walking, running, walking up or down stairs or standing still. Even though it's based on Android the principle will be the same.
I'm working on locating an iPhone device in 3D space.
I can use lat/long to detect physical location, I can use the magnetometer to figure out the direction they're facing, and I might be able to use the accelerometer to figure out how their device is oriented, but I can't figure out a way to get height of the device off the floor.
Specifically, I need to know if the user is squatting down, or raising their hand toward the ceiling (a different of about 2 meters/6 feet).
I posted a more detailed description of what I'm trying to do on my blog: http://pushplay.net/blog_detail.php?id=36
I would love any suggestions as to how to even fake this sort of info. I really want the sort of interactivity and movement that would require ducking and bobbing, versus just letting someone sit back and angle the phone -- kind of the way people can "cheat" playing with a Wii...
The closest I could see you getting to what you're looking for is using the accelerometer/magnetometer as an inertial tracker. You'd have to calibrate the user's initial position on startup to a "base" position, then continuously sample the sensors on a background thread to build a movement model. This post talks about boosting the default sample rate of the accelerometer functions so that you can get a pretty fine-grained picture of the user's movements.
I'm not sure this will solve your concern about people simply angling the device to produce the desired action, but you will have to strike a balance between being too strict in interpreting movements and allowing for differences in movement
The CoreLocation stuff gives you elevation aswell as lat/long, so you could potentially use that although there are some significant problems with this:
Won't work well indoors (not a problem for Sat Nav, is a problem for games)
Your users would have to "calibrate" (probably by placing the phone on the floor) each location they use!
In fact, you'd need to start keeping a list of "previously calibrated locations"... which could vary hugely just in one house (eg multiple rooms and floors). Could get in the way of the game.
Can't be used on moving transport (tranes, planes, automobiles... even walking) because elevation changing so frequently.
Therefore I'd have thought that using the accelerometer as a proxy for height is a substantially more preferable route than determining absolute elevation.
I am not intimately familiar with the iphone. But it might require a hardware add-on. (which you probably don't want to do). After thinking on this the only way I know how is through light or more specific laser. You shoot out a laser on the floor and record the time it takes to get back. It's actually not a lot to put this hardware together and I am sure the iphone has connections for peripherals. Unless osmeone can trump me, I say ther eis no way to do that with an image.