Does every j2me enabled mobile have GPS service so that the developer can locate its latitude and longitude?
Just because a phone can run J2ME it does not mean that it's manufacturer placed a GPS unit in it. As far as I know there are mobiles which can run Java applications but do not have a built in GPS. If you want to find the location of your phone, you can resort to triangulation, where you use cell towers to locate the phone. That being said, this method offers at best, a relatively large margin of error.
If the triangulation mechanism does not work for you, you will have to restrict your application only to GPS enabled phones.
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I am trying to build a system with a raspberry pi that allows clients access into a building depending on their membership status. Right now, it uses QR codes, but I want to know if it is possible to add a feature where it uses some technology like NFC or RFID or Bluetooth to detect their phone or RFID card from at least a foot away and confirm they have a membership.
Someone told me I could use RFID, but I am only aware of that being used in short-distance applications, like a card on a hotel door. I am not sure about Bluetooth either, because the phone would have to connect to the pi first, right? Maybe there is something I don't know about. So please offer any suggestions. Thanks
I think bluetooth does good work for tracking user. Since it's the best to handle large distances than NFC and RFID these two technologies are used for low range scenarios, check this link.
In addition, you can check distance(using Proximity and RSSI) and membership status as well. but you need to know how to handle bluetooth connectivity with raspberry pi check this link. as well create an app on that mobile phone to use Bluetooth (depending which OS you're using for Android, iOS).
Regards,
I have a number of required business cases for HoloLens that require the device to understand a general geolocation, such as the current wearer longitude and latitude within 10 meters or so, as well as sending location information to and from an endpoint during various processes. Users WILL have a mobile device with geolocation capabilities that could assist in the process if necessary, and could also be used as a WiFi hotspot.
Is this a reasonable and reliable use case for HoloLens? Can apps be created that use geolocation and maintain connectivity during an experience, either on their own or with real-time communication to and from a mobile device that has these capabilities?
Yes - definitely is a realistic scenario. I've done some integration between a blue-tooth GPS and the Hololens. Let me know the particular device you're looking at and I'll see if I can get it working with the Hololens. //Lance Larsen (Microsoft MVP) - www.lancelarsen.com
I created an application in j2me to get the current location of a device and I sent it to a nokia phone whenever I launch it, instead of showing the current longitude and latitude of the device it will open a bluetooth connection. Please help me with that what went wrong?
You may need to check what location methods you have enabled in phone's settings (in some Nokia phones, there is settings->application settings->location->my position->methods or something like that) to see if you have other methods except Bluetooth GPS enabled (Integrated GPS, WiFi, Network, ...).
But, I believe, that by default it would use internal GPS... does your Nokia really have it?
I want to be able to pair Microsoft PixelSense hardware with multiple mobile devices via bluetooth and I want PixelSense to know which device is which. So if I place two phones on a table, PixelSense should be able to label them by device name. My initial thought was to have the phone display an Identity Tag that has encoded its Bluetooth MAC address so that it could associate them but PixelSense sees in infrared and can't read the phone screen so that idea is out. Can anyone think of another way to do this?
Microsoft has demonstrated a way to do this in their Mobile Connect sample application. They've ingeniously used the fact that almost all phones have a camera that faces down when the phone is placed on a flat surface. So they created an app that will read incoming color data from Surface while the phone is sitting on it.
So it goes like this:
The Surface app starts and makes the Surface computer itself visible on bluetooth (although you may have to do this manually in admin mode, can't remember)
you run the mobile app on your phone, click connect, and place it on the Surface at a designated spot
the Surface flashes a serious of colors into the phone's camera
the phone decodes those colors into a pin and scans through all the open bluetooth devices it can see until it finds one that is a desktop running the appropriate service and accepts the decoded pin.
Now the two are connected with no need for manual input and the Surface knows which physical device it's talking to because it knows which pin it displayed to each device.
*Note - They don't actually allow multiple simultaneous connections in this sample app, but I see no reason why it wouldn't work.
One issue with this approach (other than being pretty complicated to code), is the need for the app on the phone. One way to make it easier for people to get the app is to display a Microsoft Tag or qrcode on the Surface for people to scan (they're much more likely to have a scanning app already). I don't think there's any getting around the need to have something installed on the phone if you're using bluetooth anyway.
I'm building an application where a mobile phone with an accelerometer is used to control an app on a computer in a similar way you would use a mouse. So I need to send the movement from the phone to the computer over some wireless protocol. I am thinking about using Bluetooth but I am not sure what transfer delay to expect. Another possibility is using 802.11g. What do you think? What delay could I expect given that I don’t hit the bandwidth limit?
I worked with a group at Motorola who linked up an external accelerometer pack to a mobile phone using Bluetooth. This work supported a mobile games development class at USC's GamePipe Laboratory, and the speed was sufficient to control the mobile games developed by the students. You'll need to make sure your handset's Bluetooth stack has the correct profile enabled to allow data communication.
Another advantage of Bluetooth over 802.11g is that the frequency hopping Bluetooth uses will make it less vulnerable to interference by all the other 802.11 devices in the vicinity, which sit on one frequency.
I wouldn't expect the amount of data sent by an accelerometer would give Bluetooth any problems.