Qt Serial Port: Android, iOS - will it work ?


  • Qt Champions 2016

    because of a customer request:

    who has used Qt Serial Port with Android and iOS where serial connection will be done via USB (iOS: lightning-to-usb-adapter)

    thanks for any infos, tips, success stories ;-)


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    @mrjj thx - seems it's not working out of the box. rooting the device is no option. unfortunately this blog post isn't available anymore:

    @phyatt said in Does qt support serialport in android system ?:

    I put some time into getting Qt + Android + QtSerialPort to work from a windows computer. I wrote a blog post about how I went about it. It works really well when it was all done.

    I also needed to do my own JNI calls, too, so I ended up copying the UsbJNIActivity and inserting my own code.

    http://phyatt.t15.org/wp/2015/04/qt-android-serial-port/


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    @ekkescorner
    damn. sadly it was not archived either.

    Can i ask what the goal is ?
    Maybe Bluetooth could be an option.


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    @mrjj there's a waiter lock.
    employees have magnetic keys. plug in key. waiter lock device sends unique ID via USB-Serial. also sends text if released.
    on the other side Google Pixel C or other Android Tablet with Qt 5.8 QQC2 app. if key detected, lists actual tasks on screen, employee marks solved ones, releases the key and goes on... next employee coming with key ...

    perhaps there's a converter where I can plug in the USB from waiter lock and converter sends data via BT LE or BT SPP


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    @ekkescorner
    Ah so most likely the waiter lock will act like a virtual comport of sorts.
    There is no SDK for direct interaction ? ( using raw USB)

    Depending on how device work, it might be possible with converter.
    I assume the other end of the usb cable is also usb , not serial ?
    But if anything like windows, the device will insert driver on plugin and that will
    not work with a converter as far as i know.

    Alternatively a very cheap pc (Raspberry Pi) + usb serial + BL
    http://www.usconverters.com/serial-bluetooth-adapter
    Then on pc, bridge the serial from LOCk with serial from Bluetooth and
    mobile devices just uses BL.
    But its a 3-tier solution and and might NOT be what client wants.


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    @mrjj not an easy task ;-)

    as I understand it right, Qt supports Windows for Serial Port. Perhaps the only way (without using Android native) is to use a W10 Tablet where QtQuickControls2 Apps should run


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    @ekkescorner
    I agree. It sounds like a smaller project but soon will explode in Details. :)
    Using a w10 tablet is ofc better than a pc. :) Didnt releized they are almost
    as cheap as PIs now a days.


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    @mrjj seems I found a solution for Android and iOS :)

    there's a waiter lock available supporting BT LE
    https://www.jarltech.com/2007/artikel.php?language=de&gotoartikel=addistift&suche=addlockbt14
    https://www.bluetooth.org/tpg/QLI_viewQDL.cfm?qid=33233

    got some tech info: can be used as HID or with own protocol
    HID doesn't work because then on iOS the virtual keyboard disappears
    But I got Characteristic UUID and Services UUID andcan listen for Notifications to detect if Key was put in or out

    will provide example at github (if all works as expected ;-)


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    @ekkescorner
    That could be nice solution.
    The keys looks durable so if the cradle is good it should be fine. or even excellent.
    Nice find :)



  • @ekkescorner said in Qt Serial Port: Android, iOS - will it work ?:

    @mrjj seems I found a solution for Android and iOS :)

    there's a waiter lock available supporting BT LE
    https://www.jarltech.com/2007/artikel.php?language=de&gotoartikel=addistift&suche=addlockbt14
    https://www.bluetooth.org/tpg/QLI_viewQDL.cfm?qid=33233

    got some tech info: can be used as HID or with own protocol
    HID doesn't work because then on iOS the virtual keyboard disappears
    But I got Characteristic UUID and Services UUID andcan listen for Notifications to detect if Key was put in or out

    will provide example at github (if all works as expected ;-)

    Hi,
    that sounds very promising. Did you get anywhere with it?

    We've been looking all over the place to find a suitable hardware solution for user authentication using iButton or RFID or similar tech in conjunction with iOS. All of them are either RS232, virtual RS232 via USB or HID. Nothing of that works with iOS as you pointed out already, with HID being the closest to being usable, but there is the software keyboard issue.

    So this Addimat lock that supposedly supports BT communication popped up a few times before, but it always seemed like its only using BT to connect to a PC which in turn needs a driver to turn the connection into a virtual COM port again. That didn't seem useful at all.

    There is no information about it anywhere, so I ordered one of these locks and will try to make it work. Of course, it would be very cool, if you could share how far you got already!


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    @pit.garbe Hi, I'm just making it run :)

    These are my first steps with QT and Bluetooth LE
    (Did some BT LE and NFC APPs before on BlackBerry 10)

    Noticed that the Qt BT LE Example APPs are outdated and not fully featured in respect of handling all the possible errors and states.
    (There was much progress and new things added for 5.7 and 5.8)
    So I'm just working on a new BT LE Example app using QtQuickControls2 for Android, iOS containing

    • BT LE Scanner to discover devices , Services, Characteristic, Descriptors
    • HearRate Example
    • WeightControl Example
    • WaiterLock Addimat Example

    wait a week and you'll get your Addimat Waiter Lock running out of the box :)

    BTW: I really like the way Qt is dealing with BT LE, but it's much work to manage all possible SIGNALS, error-codes, ... work-arounds for errors deep in Android BT GATT stack ... you'll get all of this from my upcoming BT LE Example APP



  • @ekkescorner That sounds great! Thanks for the heads up.

    I'm actually not coming here from Qt usage – we're working on an iOS app without Qt.
    I only used Qt before for a desktop app.

    Nevertheless, I think it will be insightful to look at your example app.


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    @pit.garbe I'm also doing iOS Apps - but WITH Qt and so I'm getting the Android APP out of the box ;-)
    For me QtQuickControls2 were the reason to go this way instead of using Xamarin, Ionic, Angular or iOS + Android native

    BTW: if you download a BT LE Scanner APP from Apple Store you can inspect the Addimat, find Custom Service and Characteristic. There's one with Notifications. Start Notifications and put the magnetic key in and out - watch the value



  • @ekkescorner The Addimat lock arrived on Friday, and indeed, using a scanner app I could verify that it is usable in the way I intent to. Great.

    I'm still looking forward to have a look at your example app, but I already want to thank you for inadvertently convincing me to buy this device after dismissing it for so long. It definitely seems to be the way to go for us :-)


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    @pit.garbe great to hear. Seems that my app will be ready this week. I'll let you know



  • I made some "fun" discoveries.

    1. Upon connecting to the Addimat lock, I always get the pairing popup.
    2. It makes no difference, what I do with that popup, I can still read the characteristic.
    3. The connection sporadically gets lost, which I can fix by reconnecting, but that shows the popup again :(

    Looking closer, using the Mac OS Console.app, I discovered that, indeed, the pairing result is always negative. Depending on which button I press (Cancel, OK) and what PIN code I enter (especially, how long it is) there are several different outcomes printed to the console. All of which clearly indicate failure to pair.

    Since there is, as I mentioned earlier, no data sheet for the Bluetooth version of the lock, there is also unfortunately no info about the default Bluetooth PIN. Maybe it's even by "design" that the lock never pairs. (I tried all kinds of typical default PINs, mind you).

    Did you also run into these problems?

    Update: I now sent an email to Addimat, asking for the PIN.


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    @pit.garbe I did most work on Android, where the OS never is asking to pair.
    on iOS - yes, the iOS is asking and you should NOT pair, because - as I understand this - this would pair the Addimat as HID and you're running into virtual keyboard problems.
    Pairing code is 308630 - never tried if pairing one time would help on iOS

    I have no problems of lost connections.
    just tried this again - no problem. Even if connecting also to another custom BT LE Device.
    Notifications from Addimat (Key in/out) and Notifications from other device (BatteryLevel and measurement of mobile network level) all ame in perfect - even while going to other Pages of the APP.
    So I'm really happy with QT BT LE.

    Only problem what could happen with Addimat: if you tottle the key while it is logged in sometimes the ID is lost (getting 0000000000000000) followed by sending the Key ID again.
    To avoid this I'm using a Timer waiting 3 seconds before doing logout. If same Key enters again while Timer is running I ignore and continue



  • After hours of comparing other code bases, where the disconnections don't happen, to mine I'm happy to announce that it was caused by a remote log viewing library that also uses Bluetooth to announce itself. Quite the discovery.

    Ok, so now I don't have the disconnects anymore, but the pairing popup remains.
    You said the pairing would make the Addimat act as a HID device? Uh, that's definitely not what I'd want. But it doesn't pair anyway. Maybe it can somehow be told to be ignored forever?


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    @pit.garbe good to hear that your disconnects are gone. for the pairing question on iOS I don't know if there's a way to avoid. perhaps Addimat can add a way ro configure the device to disable HID. will ask them.
    but for my use-case not so important: my app will be the only app running on Tablet whole day, so one time to cancel the pairing question isn't a real problem. also most of my customers will use large Android tablets instead of iPads and on Android there's no pairing question.



  • So, I got the documents. Data sheet and instructions. After reading them it's clear that paring is definitely only for HID mode. I sent a followup to both the person who sent me the docs and the one who apparently wrote the instructions, asking for a way to disable HID mode altogether.

    Btw., I just now realised that you probably speak German ;)


  • Qt Champions 2016

    @pit.garbe said in Qt Serial Port: Android, iOS - will it work ?:

    Btw., I just now realised that you probably speak German ;)

    yep - I'm living in Rosenheim


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    @pit.garbe BTW: have you tried to change the switch on the device to computer instead keyboard ? does this help on iOS ?


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    info for all waiting for my Qt 5.8 - QtQuickControls2 - Bluetooth LE Example APP:

    • finished all the work for BT LE Scanner to inspect devices, services, characteristic, descriptors and to try out read, write, notifications
    • finished my work for a customer project using a custom device to scan pegel of mobile networks (this won't be open source)
    • finished my work for a customer project using the Addimat (waiter lock) for user login-logout
    • working on HeartRate and another example
    • working on device-specific settings and device-favorites to make restart app easier with auto-connect to devices and notifications

    then have to write the blog to provide some documentation
    expect blog and app at github next week



  • Grüße aus Dresden :)

    So, I just found out by accident how to fix the popup issue.

    Simply pair the lock once as a keyboard, then navigate to the Bluetooth system settings and remove the lock there ("ignore this device"). Then it will not try to connect to the iPad again by itself. Presumably because it has its own list of known devices and the iPad is now ignoring all incoming connection by the lock.

    It can only be connected to this iPad as a keyboard again after clearing the pairing list on the lock itself. This can be done by putting the little selection dial on the bottom to the third, unmarked position (not "COM P" and not "Key Board") and plugging it in again, then off again and turn the dial back to one of the other positions and plugging it in again.

    The iPad will then be asked again to enter the PIN upon connecting to the lock.

    So, for us its perfect. Disable once and never be bothered again. Even from the iPad settings screen its impossible to reconnect again (by accident).



  • @ekkescorner said in Qt Serial Port: Android, iOS - will it work ?:

    @pit.garbe BTW: have you tried to change the switch on the device to computer instead keyboard ? does this help on iOS ?

    That didn't help. And I think its a switch between COM (serial port) and USB HID mode. It doesn't affect the Bluetooth features. Only the third setting disables Bluetooth altogether, and, as it turns out, is used to clear the pairing list.


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    @pit.garbe said in Qt Serial Port: Android, iOS - will it work ?:

    Grüße aus Dresden :)

    thx

    So, I just found out by accident how to fix the popup issue.

    Simply pair the lock once as a keyboard, then navigate to the Bluetooth system settings and remove the lock there ("ignore this device"). Then it will not try to connect to the iPad again by itself.

    will do this next time testing the lock on iOS. Doing all my work on Android and only from time to time verify if all works and looks good on iOS, too


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