I have a HoloLens, and I want to interact with the API's. Unfortunatetly, it keeps going into standby mode, even when plugged in. This means I have to wear the HoloLens like a hat to keep it on. Even though I'm not trying to physically use it.
Is there anyway to keep it out of standby mode when it is plugged in?
You can set the behavior when plugged if you enter the Device Portal (enter the IP of your device in a web browser).
Related
Since the latest update (I think some time in December 2022), the built-in camera app on my Samsung Galaxy S21 asks for "Nearby devices" permission, and refuses to run if I don't grant it. By "Nearby devices" it means "Bluetooth". I don't know why it calls the permission
"Nearby devices": all other references to Bluetooth call it "Bluetooth",
and you can also access a nearby device using Wi-Fi or even NFC if the device
is close enough.
It doesn't actually need Bluetooth to take photographs, or even to record movies,
but you might have a Bluetooth microphone (I don't) and you might want to use
it to get better sound quality when recording a movie.
Of course the Android best practice advice at
https://developer.android.com/guide/topics/permissions/overview
is not to ask for runtime permissions unless and until you need them,
but Samsung aren't doing that.
I don't want the camera app to announce my presence by probing the Bluetooth headset of
anyone who happens to be near me, and they might regard such an action as intrusive.
So I don't want to give the camera app its nearby devices permission, but it won't
run at all without it.
So how do I get the camera app to run without accessing Bluetooth?
I found some workarounds for this. If your device supports it, you can download Expert Raw from the Galaxy Store. This will take still photos without requiring "Nearby devices" permission. However it doesn't seem to be able to do selfies because there seems to be no way to switch cameras, and it can't do movies or many of the extra tricks that the full camera app can do.
Another option is to run the camera app with Bluetooth disabled. Then it can have its "Nearby devices" permission, but it can't use it. The problem with this is that if you use Bluetooth at other times you have to remember to disable it and enable it.
So I wrote a tiny app which disables Bluetooth, runs the camera app, and restores the previous enabled or disabled state of Bluetooth when the camera app exits. I put this on my home screen instead of the camera app: it has the same icon. You have to remember to exit properly from the camera app using the Back button: the Home or Recents buttons leave my app and the camera app sitting on the task's back stack, so my app doesn't get to run and restore the Bluetooth state.
The app is available on github here in case anyone else wants to use this solution.
I'm trying to establish a connection between my PC running Ubuntu and my iPhone via Bluetooth automatically when it becomes available, after being manually paired beforehand. I've seen this to be possible with certain peripherals, mainly audio. For example, my phone will automatically connect to a Bluetooth speaker when it is turned on and Bluetooth is active on my phone; another example is my phone automatically connects to my car's radio system via Bluetooth when I turn the car on.
I'm not able to connect my phone to my PC without first initiating the connection from the smartphone's Bluetooth menu. I'm thinking that I could possibly write an application for the PC to attempt to connect to the device every few minutes or something, but it seems that the phone needs to be the device to initiate the connection.
The only information that I need for what I'm trying to do ultimately is that the devices can pair successfully. Essentially I'm trying to build a sort of proximity trigger between my phone and my PC without using Wi-Fi and GPS - I can't use these for some specific reasons.
Is there any way to make this happen?
Yes this should be doable as long as you use the Background Processing feature for iOS apps. In the example I'll give below, we'll have the PC be the peripheral and the phone be the central, but you can really have it working either way. You will need to do the following:-
First initial connection needs to be performed in the foreground (this is due to iOS's background limitations).
On the iOS side, you need an application that acts as a central that scans and connects to the remove device (check this example as a starting point).
Upon connection, you need to bond with the PC. Bonding is important as it will prevent you from having to do the pairing again in the future. However, pairing/bonding is managed by the iPhone's OS so you cannot write it in your application, so the workaround is to have an encrypted characteristic on the PC side that will force the iPhone to bond (this is covered later).
On the PC side, you need to have a BlueZ script that acts as a peripheral that is always advertising. You can do this using bluetoothctl (check the examples here and here).
Before you start advertising, you need to have a GATT server on the PC side (to do this, check this example).
When registering characteristics, ensure that one of them has the encrypt-read property (you can find a full list of the properties here).
Now when you attempt to read this characteristic from the iOS side, the two devices should bond (make sure that your PC is bondable which you can do this via these commands).
Once the devices are paired, your iOS app needs to be working in the background constantly scanning and attempting to connect to the same peripheral (have a look at this and this example).
You can find more useful information at the links below:-
Getting started with Bluetooth Low Energy
The Ultimate Guide to CoreBluetooth Development
How to manage Bluetooth devices on Linux using bluetoothctl
I bought a cheap bluetooth smartwatch that costed like $20.
When I plug it into my computer, I cannot see the device listed. I cannot think of any other way to access the source code.
The reason I am trying to get at the source code is to add a few of my own watch faces and try to create my own features.
Any help?
I guess under "plug in" you meant you've plugged it in the USB charging port. Most probably communications are disabled there by a default and the port is in charging only mode.
Try to pair it with your laptop via Bluetooth first, then try to access your watches as a bluetooth device (there is an option for the file transfer, for example, for windows see here: https://support.microsoft.com/en-us/help/4026874/windows-10-share-files-over-bluetooth).
I have built a home surveillance and alarm system with raspberry pi's.
What I need now is an easy and safe remote control to arm the system and disarm it.
The most workable solution is to have a wireless router in the middle.
Before stepping out in the door, take out my phone, connect to my home network and via a custom built web page arm my system. (Web page would run the arming scripts)
But for this I need to have a wireless router (currently I have a non wireless Ubiquiti Router Station Pro, no radio card on it) and need to enable wireless on my phone (it is not enable-d, battery reasons) before leave, connect and so on. It is not one click unfortunately...
Other solution is to have just a wireless dongle in the Raspberry PI and do an Ad Hoc WiFi connection with my phone. My phone is Sony Ericson Xperia. Over here my technical knowledge hits the limit. It is possible to broadcast an Ad Hoc network over Raspberry PI I do not know if I can reach it from my Sony Ericson Xperia phone.
Third option is Bluetooth. I know very little about Bluetooth. I do not know how safe it is, and how to program it, to have on and off switch on my phone. However this might be the most promising.
Fourth option is to use the Pi Face. Link one or two switches to some type of receiver device. Have a sender device on my key chain and control it from there.
However I do not know from where I can buy such a safe remote control and if it is compatible with Pi Face.
Fifth option. To get home alarm system components and link those with the Pi Face. But I do not know what component might fit.
The best user scenario is the following.
User takes out out a device (phone or remote control) and presses arm/disarm.
User has appropriate time (30 sec) to get out or shut down.
If the remote device had run out from battery still have something to shut it down.
So my question does any body knows a fast, easy, cheap solution how to do this?
Though Bluetooth's security is questionable, it seems like the best option for your goal. Next to an adhoc
Bluetooth is not complicated.
On your mobile phone, if you don't want to make your own app you can look for some sort of Bluetooth Terminal or Bluetooth Chat. On your raspberry pi you'll have to setup a bluetooth rfcomm server with bluez.
How to configure Linux to act as a Bluetooth RFCOMM SPP server?
RFCOMM without pairing using PyBluez on Debian?
Modify these servers which do nothing by default, to listen for commends "arm" and "disarm". Make sure the ID of the device is the ID of your phone.
Ad-Hoc is even less complicated (assuming you know how to make a webserver and are going to make it secure enough, and have a dongle which supports adhoc):
Here is a post about ad-hoc networking with a raspberry pi.
In terms of distance, you'll have to see the specifications on your dongle(s) but I would say they're relatively the same.. your bluetooth dongle will have a class see Bluetooth Basics: Range. This will require more research but if you have either one of the dongles I would use that method.
I hope this helps, good luck setting up your alarm.
In the mean time I realized that a fast arming could be done via the Pi Face and pressing a button.
Disarming could go by other ways.
However the fastest solution would be a fingerprint button linked safely to Pi Face.
Updates. Finally went with the Ad-Hoc method:
This is the tutorial for it:
http://elinux.org/RPI-Wireless-Hotspot
my .net app on the computer needs to make the computer discoverable, start a service and then wait to accept incoming connections. my app/computer is the slave and connecting device is the master. So I change my local radio mode to discoverable programmatically,start my service and wait... But when the device is supposed to connect to my app/computer, nothing happens.
Windows help and support has this :
Control Panel ->search for bluetooth -> click on change bluetooth settings ->
To make your computer discoverable to Bluetooth enabled devices,
select the check box for Allow Bluetooth devices to find this computer.
When a Bluetooth enabled computer is in discovery mode, it broadcasts a
wireless signal that allows it to be detected by other computers or devices.
This is sometimes called pairing mode. If you check this box, your computer
will still be able to detect Bluetooth enabled devices that are in discovery mode,
but they will not be able to detect your computer.
I am not quite sure what's the context. If I leave that box checked, then other devices will be able to detect me (because I am set to discoverable), but won't be able to connect????? So my service just keeps listening, won't be able to detect any incoming requests? Am I right?