Recently, while developing an app on the iPhone, I came across the problem of tracking vehicles. It was easy to track the vehicles on a map if they were stationary using Parse ( although not sure if it was the best method) but the issue was tracking vehicles if they were moving. I didn't want to query for geopoints in Parse unnecessarily if the location of the vehicle did not change. I was steered towards using Twisted, and after doing some investigation, realized this might be a solution. Using the reactor loop, when locations were changed I could notify the other users and update their maps appropriately. Conceptually, I understand this problem but having trouble finding information or help regarding GPS with twisted.
I currently have been running the gps example from the site, http://twistedmatrix.com/documents/12.0.0/core/examples/gpsfix.py
Using my MacBook pro to test, I found the available serial port and it attempts to open as a NMEAReciever but I was expecting a GPS location to be written. Once I can understand how to interact with the GPS, I feel I could tackle communicating this information through the iPhone with NSStreams such in the fashion of this tutorial except instead of sending text messages, it will be sending GPS locations
http://www.raywenderlich.com/3932/networking-tutorial-for-ios-how-to-create-a-socket-based-iphone-app-and-server
Overall, my question is how can I access the GPS coordinates of a device using Twisted through the tutorial provided. I hope my question was detailed enough and I would be more than happy to correspond with someone any more details. Thank you
I (eventually) wrote twisted.positioning, which is essentially a better version of the twisted.protocols.gps thing you're using. It has much nicer abstractions over concepts like positions, as well as receivers. That may be interesting to you, because it provides abstractions that you can use to e.g. combine information from GPS and other sources (like compass). However, I think that in iOS-land, that job is already (mostly) handled by Core Location. I'd assume that the best course of action is too hook that up to twisted.positioning (shouldn't be particularly difficult, can't be anywhere nearly as hard as NMEA is, at least!). Lacking iOS development experience, I can't tell you how to access Core Location from Python; I can only point at the docs.
twisted.positioning is also an improvement when it comes to documentation. Unfortunately, that wasn't very difficult, because its predecessor came with none at all. I hope the one scant example that is provided helps, though; and I'd be more than happy to elaborate if it doesn't.
Related
I work on an application for custom fit eyewear, and we've been using Bellus3D's iOS SDK for getting facial geometry, including landmarks like pupils.
Bellus3D has decided to wind their business down by the end of 2022, and I'm looking for a suitable replacement framework for our application. Bellus was great because it produced reliable results in exchange for a pretty simple user experience.
I've found a few apps that also use or used Bellus, but not getting any word about what alternatives they've found that would suitably replace it.
Scandy doesn't seem to be accepting new SDK registrations
Standard Cyborg took some tweaks, but works great, and their API tokens work, but I can't find any information about their pricing and they're not responding
Topology Eyewear seems to have a solution, but not a lot of details and aren't responding either.
I've reached out to a few app developers that incorporated Bellus 3D, but so far all I've heard is that they're in the same situation.
Does anyone know of a working, maintained solution for 3D face scanning with cell phones (or 3D scanning in general), or of an approach to get something with decent fidelity out of ARKit
This isn't necessarily a specific code question, but more just hoping that someone might be able to point me in the right direction. I'm making an outdoors/hiking app and one of the features I'd like to build is a trail progress tracker. I've seen other apps that do this, namely maps.me, and it somehow is able to continue to track your location on a topo map even after gps and wifi are inaccessible. I've been trying to research information on how this is done but coming up with nothing, possibly because there's maybe some terminology involved that I'm not familiar with. If anyone can offer any links or hints as to what I should be looking up in relation to this, that would be fantastic.
Thanks!
I'm nxj beginner.
I have some questions about bluetooth communication between PC and brick.
First, when bluetooth communication occurs, where is the birthplace processing this datas?
In other words, I want to know whether these datas will be processed on CPU or brick.
Second, what is exact roles CPU and brick in bluethooth communication?
That means what is processed on CPU and what is processed on brick.
I have searched almost web site but I can't find this anywhere.
Please help me. Thanks.
You can see it in the package structure.
lejos.nxt.*
This package contains classes running on the NXT-brick. All code in this package will be compiled for the brick and will run on the brick.
lejos.pc.*
Here the difference is not that clear. This is java-code you compile for personal computer. So most code runs on your computer. But some classes (e.g: RemoteMotorController) only send messages to the NXT-brick which gives commands to the motors.
lejos.pc.comm provides API's that allow you to communicate/control the nxt robot from the PC.
When importing the the libs to an Android project, it allows you to build an instance of the same environment used on a pc, but within android.
I agree it can be tough finding some things out. It would be great if there was as stronger lejos presence on SO
This question is months old and has remained un-answered I actually have a lot of questions about it myself, but I might be able to provide some insight for utter novices.
when using bluetooth with Android and NXJ robots, you use either lejos.pc.comm or lejos.NXJ.
Both provide APi's to do almost the same thing, but work a little differently. I don't know nearly enough about the NXJ api, but I do know that it is the one that lets you manipulate the robot much more effectively, such as outputting data to it's LCD screen, which you can't do with the pc.comm api
As far as I can tell, the pc.comm API uses both Android Bluetooth API's and it's own protocols to allow communication with Lego LCP commands.
(I want to come back to this, but I'm writing a dissert on the topic so I'll try to update it in a couple of days. Seems not many are interested though, shame)
All,
Apologies in advance - this question might be too open-ended for SO.
Anyway... A friend of mine (an engineer and entrepreneur) is in the process of building a high-tech piece of lab equipment. He's asked me about the feasibility of building an iPhone/iPad/iPod application that would allow users to control the device via Bluetooth, so I'm helping him gather some information. I'm hoping to get a few pointers on how to get started. Specifically:
Would this require a native app, or could this be accomplished with HTML5 (with or without something like PhoneGap?)
Can you point me to a good primer on bluetooth networking? Everything I've found assumed a VERY high level of pre-existing knowledge.
What are the basics on how something like this is accomplished? Is there a single, established protocol for how one device "controls" another, or is bluetooth more like SSL - just a pipe that allows you to convey any type of message?
I realize this question is incredibly broad and detailed - so I'm not really looking for specifics. But obvious Google searches don't turn up much, and I'm otherwise having a hard time finding a good starting point.
Thanks in advance.
You can communicate via bluetooth in two ways: One is using the Low Energy Bluetooth capabilities of iOS 5 and newer iPhone/ipads.
https://developer.apple.com/library/ios/#documentation/CoreBluetooth/Reference/CoreBluetooth_Framework/_index.html#//apple_ref/doc/uid/TP40011295
Unfortunately the documentation is sparse and will require some hacking away. If you choose this route I would consider starting here and learning as much as you can about how the protocols work before hacking into the framework:
http://developer.bluetooth.org/gatt/services/Pages/ServicesHome.aspx
The limitations of this route are that it might not be best for sending a lot of data. I have only built stuff that sent simple commands which it does work great for.
The other option is the external accessory framework. This will require you to get an mfi license from apple (not fun). You will also need to pay royalties. But it will do what you want. You won't need to concern yourself much with underlying protocols if you use this, the framework provides a friendly api for processing streams.
http://developer.apple.com/library/ios/#documentation/ExternalAccessory/Reference/ExternalAccessoryFrameworkReference/_index.html
Is it possible to get location data out of Google Gears, Google Gelocation API or any other web location API (such as Fire Eagle) in such a format that it appears to other software as a GPS device?
It occured to me reading these answers to my question regarding WiFi location finding, on Super User, that if I could emulate a GPS unit, many of these web services could act as a 'poor-mans' GPS to otherwise less useful software that requires it.
Is GPSD an option?
Preferably OSX & Python, but I would be interested in any implementation.
There is a very similar thread on a Python mailinglist that mentions Windows virtual COM ports and discusses Unix's pseudo-tty capabilities. If the app(s) you want to use let you type in a specific tty device file, this may be the easiest route. (Short of asking the authors to provide a plugin API for what you're trying to do, or buying yourself a $20 bluetooth GPS mouse.)
Are you using OS X?
There is a project macosxvirtualserialport on Google code that provides a graphical wrapper around some of the features of a utility called socat. I'd recommend taking a look at socat if you see potential in the pseudo-tty route. I believe you could use socat to link a pipe from a Python program to a pseudo-tty.
Most native Mac apps will be querying IOServiceMatching for a device with kIOSerialBSDRS232Type, and I doubt that a pseudo-tty will show up as an IOKit service.
In this case, unless you can find a project that has already implemented such a thing, you will need to implement a driver as described in this How to create virtual COM port thread. If you're going to the trouble of create a device driver, you would want to base it on IOKit because of that likely IOServiceMatching query. You can find the Apple16X50Serial project mentioned in that post at the top of Apple's open source code list (go to the main page and pick an older OS release if you want to target something pre-10.6).
If your app is most useful with realtime data (e.g. the RouteBuddy app mentioned in the Python mailinglist thread can log current positions) then you will want to fetch updates from your web sources (hopefully they support long-polling) and convert them to basic NMEA RMC sentences. You do not want to do this from inside your driver code. Instead, divide your work up into kernel-land and user-land pieces that can communicate, and put as little of the code as possible into the kernel part.
If you want to let apps both read and write to these web services, your best bet would probably be to simulate a Garmin device. Garmin has more-or-less documented their protocol in the IntfSpec.pdf file included with their Device Interface SDK. Again, you'd want to split as much as you could into user-space code.
I was unable to find a project or utility that implements the kernel side of an IOKit-based virtual serial interface, but I'd be surprised if there wasn't one hiding somewhere out there. Unfortunately, most of the answers I found to that question were like this, with the developer being told to get busy writing a kext.
I'm not exactly sure how to accomplish what you're asking, but I may be able to lend some insight as to how you might begin to get it done. So here goes:
A GPS device shows up to most systems as nothing more than a serial device -- a.k.a. a COM port if you're dealing with Windows, /dev/ttySx if you're in *nix. By definition, a serial port's specific duty is to stream data across a bus, one block at a time. So, it would then follow logically that if you want to emulate the presence of a GPS device, you should gather the data you're consuming and put it into a stream that somehow acts like an active serial port.
There are, however, some complications you might want to consider:
Most GPS devices don't just send out location data; there's also information on satellite locations, fix quality, bearing, and so on. Then again, nobody's made any rules saying you have to make all that data available. There's probably more to this, but I'll admit that I need to do more research in this area myself.
I'm not sure how fast you can receive data when dealing with Google Latitude, etc., but any delays in receiving would definitely result in visible pauses in your "serial port"'s data stream. Again, this may not be as big a complication as it seems, because GPS devices are known to "burst" data across the bus anyway, but I'd definitely keep an eye on that. You want to make sure there's always a surplus of data coming across, not a shortage.
Along the way you'll also have to transform the coordinates you receive into valid GPS sentences, as well. You can find specifications for those, but I would definitely make friends with the NMEA standard -- even though it is a flawed standard, it's the one everyone seems to agree on anyway.
Hope this helped you, at least a little bit. Are there anymore details specific to your problem that you think could be useful in answering this question?
Take a look to Franson GPS Gate which allows you to connect to Google Earth among other things (like simulating GPS and so on). Is windows only though but I think you could get some useful ideas from it.
I haven't looked into it very much, but have you considered using Skyhook's SDK? It might provide you with some of what you are looking for. It's available for every major desktop and mobile OS.