provided GPS will not work precisely in closed environment like rooms etc,I m interested to know whether Accelerometer can be used to find the position of object relative to certain point? If not then what other technology iphone4 provides to cater it?
Thanks
The accelerometer cannot reliably provide location information, even with the aid of the gyroscope. GPS is the best you are likely to get.
OTOH, work-arounds abound in the augmented-reality space. Consider the ARDefender game.
Related
Good day!
Problem definition:
Current implementations of Bluetooth does not allow to simply support good quality of Audio(Earphones mode) and 2-way audio transition (Headset mode).
Also, even if one would manage to set this configuration up, which have huge limitations on the hardware/software used, there is no way to handle sound input from 2 different audio devices simultaneously.
So, technically - one cannot just play the Game, communicate on the Discord, and optionally listen to some music, unless he is bound to some USB-bundled earphones. Which are usually really crappy, or really expensive. Or both.
Solution sketch:
So, I came up with an idea that one can actually build such device, using Raspberry Pi, Arduino, or even barebone-component-based stacks.
Theoretical layout of connections per-se would look somehow like that:
Idea is to create 2 "simple" devices
One, not-so-portable, that would handle several analog inputs, and one analog output
One, portable, that would handle single analog Input and Output, and could be used with any analog earphones.
"Requirements" to such system would be quite simple:
This bundle have to handle Data Transition on some distance, preferably up to 10 meters, or more.
The "Inlet" device should be portable enough to keep it in the pocket, or in an arm band, or something
Sound Quality should be at the very least on the level of Bluetooth headphones profile, or if possible - even better
If possible - it would be nice to keep the price of the Solution under 500 Euros, but I'm so tired of current state of things that I might consider raising the budget...
Don't mind the yellow buttons on the Outlet device. Those are optional, and will depend on the implementation stack :)
Question:
Can anyone advice me which component-base would be a better solution to making such a tool, and why?
And maybe someone actually knows of similar systems already existing?
Personally I would prefer anything but the barebone-components-based solution, just because I'm really rusty with that area, and it requires quite the amount of tools, to handle it properly.
While using pre-built modules can save me from buying most of the hardware tools, minifying my "hardware customization" part of this solution, leaving only software part to handle (which is my main area of expertise).
But then again, if there are some experts here, that would consider other stacks non-viable - I would really appreciate to see their reasonings.
P.S. Just to be clear: If this project will prove viable - I will implement it, and share the implementation details with the communities. I am not the first one who needs such system, and unfortunately it seems that Hardware/Software vendors are not really interested in designing similar solutions...
I happen to find a "temporary" solution.
I've came across a wireless headset, that allows to simultaneously support Wireless USB Bundle connection, and Bluetooth connection to different devices, and provide nice way of controlling sound input/output with both connections.
This was almost a pure luck, as this "feature" was not described anywhere in the specs...
Actual headset name is:
JBL Quantum 800
This does not closes the question per-se, as I still plan to implement this "Summer Project" at some point, but I believe this information might be useful to those searching for similar solutions.
I know, this question has been asked a lot of times. Until yesterday i thought that the answer was "yes, it is possible but you can not obtain an accurate result of your position". My idea is to take a BLE badge in my hand and with other 4 devices, positioned on the ceiling, obtain my current position using the trilateration. After weeks of resarch, i concluded that this method could not be as accurate as i'd like it to be, so i went over.
Now, what about this video? Youtube by Loopd.
They use bluetooth badges, but how they obtain these results?
Thanks to everyone
The results of Bluetooth LE indoor location can be quite accurate, but it requires some processing of the raw signals rather than simple triangulation. Essentially you weight different beacons differently in your position calculation based on how far away they are and filter to smooth the result.
There is a working example as open source at http://vor.space/
I am using a MPU6050 IMU to map the path of a device (with starting point as origin). For this I need to convert the accelerometer and gyroscope readings into (Cartesian)co-ordinates. I think I need to continuously sample the accelerometer readings and go on adding (integrating) the sample to the previous point for each axes respectively. At startup the previous point will be (0,0,0).
I know this on paper. But I dont think it will be that simple. How will I know when the device is moving backwards, ie towards the origin?
The MPU6050 provides accleration and gyro reading in all axes. I used this to fetch the values. But I dont know how to continue. So what I need is an "Inertial Navigation system" which takes acceleration and angular velocity vectors as well as the current position as input and returns the new position. I know this will have errors, but I am not concerned about that for now.
If someone can guide me in this that would be great. Any hints or pointers will be appreciated.
Kiran G
Kiran,
To answer that question it would be good to know what kind of Gyro are you using or willing to use. It is very different depending if the output is an analog signal (voltage or current loop) or if that is any kind of (normally serial) bus.
Please note that most likely you will have also to filter the signal based on the expected dynamics of the environment.
I was wondering if there was an existing API for tracking the top of people heads with the Kinect. e.g., the Kinect is facing downwards from a ceiling.
If not, how might I implement such a thing with its depth data.
No. The Kinect expects to be facing a standing (or seated, given the appropriate flag) human. All APIs (official or 3rd party) that have a notion of skeleton tracking expect this.
If you wish you track someone from above, you will need to use a library such as OpenCV (or EmguCV, for C# development). Well, you don't have to, but they offer utilities to help with computer vision and image processing. These libraries don't care if you are using a Kinect or just a regular RGB camera.
Using the Kinect from above, you could use the depth data to help locate and track blobs. With the Kinect at a known distance from the floor, have a few people walk under it and see what z-coordinates you get out of it -- you can then assume that anything within a certain z-coordinate range is a person walking across the screen (vs. a cat, or something else).
You will need to use standard image processing techniques (see OpenCV reference above) to initially find the blobs within the image. Once found, the depth data from the Kinect might be useful but I think you'll find it isn't ultimately necessary if you're just watching people walk across the floor.
We built a Kinect-driven experience where the sensors had to point downward to detect users walking along a wall. We used openTSPS to do all the work of taking the camera input and doing blob detection and handing off tracked "persons" to (in our case) a Processing app. It works really well for us.
http://opentsps.com/
I want to read the framebuffer of the videocard at the lowest level possible for a security application I'm writing.
I want to be as sure as possible that what I'm reading is exactly what will be finally
put on the bits of the hardware lighting the pixels of the screen,
and that no software layer is in the middle (or at least I want to have the lowest number possible of layers in the middle).
I've seen it's pretty easy to use X to grab the screen in a precise moment, but that call
is still passing through the X server.
I would like to have something really more low level,
even if this means messing up with some ioctl with the video card.
I've seen the existence of DRI and DRI2, but they are very very badly documented, especially
the latter.
I can't really understand how they work.
Do you have any idea, reference or starting point for a good research?
Anything would be appreciated!
I'm not sure how much reading the framebuffer will help you (even disregarding the issue pointed out by timday in his comment, deciding whether what you read there is what you want it to be may not be very easy), but if you are doing this on Linux you could map the kernel framebuffer devices, possibly using DirectFB to help you. Alternatively, if you are on a non-Linux PC platform you could use VESA (take a look at the VESA code in X.Org and the X.Org VESA driver (the actual code is split between the two). Be aware that you will probably also have some fun with things like multi-monitor setups.