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How to Use Your Android Tablet as a Second Monitor

74 points by rodrigo975 6y ago

pizza234 6y ago
I needed a similar setup some time ago, and I was so frustrated by the Linux remote desktop open source solutions, that I ended up using Nomachine, which turned out to be very impressive. I'm mystified by the enormous gap between the open source solutions and Nomachine, both in the technical and usability areas. The open source solutions are sadly terrible; those who aren't convinced, just try Nomachine. It's puzzling because solutions like X2Go (which I found to be the most usable) rely on older NX protocol versions (v3 was open), but still, they have terrible performance. This means that in the last 10 years, there has been no virtually development in the open source remote desktop field.
- FpUser 6y ago
  Nomachine is my savior. I love it.
- Fnoord 6y ago
  Have you tried xrdp? Here's an example usage [1]. Your X server would run a sort of RDP emulation layer, and then any RDP client works. Obviously you'd tunnel it over a VPN or SSH. I haven't used NoMachine in like 10 years or so. Back in the days (~15 years ago), I used to run it on UltraSPARC machines running Debian and Gnome. It worked marvelous, even with a FOSS server (FreeNX IIRC). It even worked on the Nokia N-series! Although it sucked to run it on a Mac; you had to run a complete X server, which looked terrible (including the fonts). [1] https://github.com/deskor/xrdp https://github.com/deskor/xrdp
  - high_priest 6y ago
    I've tried xRDP and it is still as terrible for fluid workstation interactions as is the whole RDP protocol. Sending only changing parts of the display is a great concept for data use reduction, but a quick x264 compression and simple input replication works much better on systems with 100Mb+ connections
  - pizza234 6y ago
    Yes (specifically, the original distribution (https://github.com/neutrinolabs/xrdp https://github.com/neutrinolabs/xrdp) and the one provided in the repository of my o/s), and it fell flat on the usability side - gave me a blank screen after logging in. Gave up after an hour or two of attempts. X2Go worked straight out of the box, but it's very slow (on a 10 Mbit home wifi connection).
    - bleepblorp 6y ago
      Xrdp has horrendously bad documentation and installation scripts but it does mostly work after configuration. You have to manually edit /etc/xrdp/startwm.sh to make xrdp launch a desktop environment when it accepts a connection. If you don't do this, you'll get a blank screen or something non-useful, like a session with just one Xterm window and no desktop environment. Note that Linux does not support shifting sessions from the local keyboard, mouse & screen to remote access. Further, the major desktop environments don't support simultaneous sessions from the same user. With any of the remote access tools that don't simply take over the local screen and keyboard, if you have an active session on the physical screen, you won't be able to connect to it remotely, nor will you be able to start a new session remotely under the same login. you'll need to log out from the physical screen before attempting a remote connection. Finally, Xrdp clipboard sharing does not work with Linux clients.
- derrick_jensen 6y ago
  I also hate all open source Remote Desktop solutions, but I ended up using SPICE with Proxmox. Nothing else will forward audio and handling Remote Desktop at a virtualization level is the most reliable and flexible of everything else that I have tried. Only downside is that it doesn’t work with LXC containers, but that’s not a big problem considering only five or so machines need graphics. EDIT: another downside is lack of client support on iOS. I’d love to work on my iPad with a Magic Keyboard but no client exists that handles SPICE AFAIK.
- papasamba 6y ago
  Can you please explain how you setup nomachine to use your Android tablet as a second monitor
amelius 6y ago
I don't understand the need for more than one monitor. Just setup your desktop so you can switch virtual workspaces with a key combination. It's faster than turning your head.
- goihoiholi 6y ago
  That's your work style then. In many cases, I got the documentation on one screen, and my IDE on the other. Other times, it's more a distraction (i.e., whenever I just have mail or WhatsApp on the other) -- I'll turn off the second monitor then.
- soreine 6y ago
  Yes, most of the time you only need one screen, two screens mostly generate distractions. But I have noticed that switching workspaces is a context switch for your brain, just like passing through a door. You often forget what you were doing right after leaving a room for that reason. And when I truly need two different windows in a shared context, like some documentation in the browser and my code editor, it saves effort to have them truly side-by-side.
- skocznymroczny 6y ago
  I think it depends on the person. I also prefer one monitor. I'd rather have a big monitor than several screens. Also, I never really have more than one window open at a time. I don't mind switching between windows. But some of my coworkers swear by multiple screens and one app per screen. I think it's the same with tab management in the browser. I average 4-5 tabs open at a time, never really going above 10. But many of my friends are rolling with 80+ tabs at a time.
- cbertoldi 6y ago
  Another good example of why two monitors are useful is to have on one your favourite confenerence program with all the nice videos from your colleagues, and on the main one the page/board whatever you are discussing about. I.e. a Confluence page with collaborative editing on one monitor and Zoom/Teams on the second one.
- blisterpeanuts 6y ago
dvfjsdhgfv 6y ago
"8-bit Buddhism" sounds even worse than 2-bit Islam. Honestly people, think a bit before choosing a name for your tech blog.
- t-writescode 6y ago
  I believe it’s a reference to the 8-fold path, and I thought it was quite creative: https://en.m.wikipedia.org/wiki/Noble_Eightfold_Path https://en.m.wikipedia.org/wiki/Noble_Eightfold_Path
  - timbit42 6y ago
    Wouldn't it be more clever to call it 3-bit?
- GavinMcG 6y ago
  8-bit and two-bit have very different meanings and connotations.
ant6n 6y ago
Mmh. There are external, portable usb-c monitors, which are convenient because you can plug them into any usb-c laptop. But they are „dumb“, only work in connection with a laptop. I wonder whether there is one that can act as an Android tablet when not plugged in.
- pella 6y ago
  there is a hope: "Lenovo working on dual-purpose Android tablet and external monitor, ‘Yoga X’" https://9to5google.com/2020/07/10/lenovo-yoga-x-android-tablet-external-monitor/ https://9to5google.com/2020/07/10/lenovo-yoga-x-android-tabl...
- chiefalchemist 6y ago
  True. But I've looked at various small portable screens and they're rather expensive. The advantage of using something you already have is you save money and it's one less thing to carry. That aside, I struggle to understand why laptop to tablet still requires magic in 2020? Are manufacturers afraid of cannibalizing sales for one line to another?
  - ant6n 6y ago
    Well I travel a fair amount for work and would like to have an external monitor for the work laptop, but also a personal tablet. With a 2-in-1 device I could solve both concerns without adding too much travel weight.
- Fnoord 6y ago
  I'm looking for one to combine with my MBP 2015 which has TB2/HDMI. However, even if ignoring that requirement, from what I can tell these all have terrible brightness. I, for one, cannot stand such.
reportgunner 6y ago
... or you could just use TeamViewer or any other screensharing software without all the hassle if you really think that using a RDP is a "second monitor".
- arnoooooo 6y ago
  This actually allows you to use both screens and move windows from one to the other. Not at all the same as just screensharing.
HMH 6y ago
This is quite similar to my latest project Weylus [1]. You still have to create the virtual output yourself but then you do not only get a second monitor but all the touch events are handled properly and you can even use a stylus/pen with pressure sensitivity. Additionally it also works on iOS/iPadOS. [1]: https://github.com/H-M-H/Weylus https://github.com/H-M-H/Weylus
- _frkl 6y ago
  Oh wow, pretty impressive. Have to try that out tomorrow!
nemacol 6y ago
This is neato but I would suggest you splurge for the USB monitor if you can. Still can't watch movies on it, but they are great little screens for the money. My main issue is, without a stand, they sit on the table and are uncomfortable to use for long periods. The ones I have used are VESA mountable though - so it is a problem with an easy solution.
- zwieback 6y ago
  My employer gave us a small budget to improve our WFH setup. I bought a USB "monitor" with a cover that folds back into a stand. I'm surprised how much I ended up liking this.
gambiting 6y ago
I bought a cheap £20 windows tablet from ebay(an old Tesco Connect 8 tablet), put windows 10 on it, and now I can seamlessly connect it as a second screen from anywhere, the windows "remote screen" feature is incredible for that. With 2 clicks it shows up as a regular secondary monitor that I can just drag things onto.
- jonathanlydall 6y ago
  I'm a big user of Remote Desktop on my Windows 10 computers, but am unaware of any "remote screen" feature. I did a quick internet search but couldn't really see any information about such a feature built into Windows. Could you tell me more about how you achieve this?
  - soylentcola 6y ago
    I believe this is the Miracast feature that was common for a minute on some TVs and other devices but sort of fell by the wayside later on. You can mirror or extend your screen from one Win10 device to another Win10 device on the same network (assuming, of course, that it's not some sort of locked down or public wifi, etc.) Please correct me if I am wrong, as I've not used this function in probably a year or more.
    - gambiting 6y ago
      Yep, on one Windows 10 machine you need to go to Settings->Projection Settings, switch it on there, then from another Windows 10 machine you can simply press Win+P and select "connect to screen", then click on the other machine name. The only caveat is that both machines have to use Wi-Fi - it doesn't work over LAN at all. And yes, I believe it uses Miracast underneath.
      - 0xffff2 6y ago
        >both machines have to use Wi-Fi - it doesn't work over LAN at all This has to be one of the most baffling statements I've ever read on the internet. What on Earth could the possibly be doing that this is the case? Edit: Never mind. Another comment says that it's actually a feature of certain Intel WiFi chipsets, so it's not that you have to be using WiFi in general, it's that both devices have to be using specific Intel WiFi chips that support the feature.
kkapelon 6y ago
or you can simply use spacedesk.. https://spacedesk.net/ https://spacedesk.net/
- Fnoord 6y ago
  Caveat emptor: server runs on Windows only.
gbraad 6y ago
Use spacedesk or miracast if your device supports it
bjoli 6y ago
This is tangential to something I want to achieve: I have a 2016 iMac. Does anyone of you know if I can use that as a second display? Apple removed target display mode, which means the Mac with it's amazing screen is collecting dust. I have used it to ssh into my Linux machine and have it as my main terminal and documentation viewer machine using synergy, but that is tiresome.
- mronge 6y ago
  Yes! We built that into Luna Display: https://shop.astropad.com/pages/meet-mac-to-mac-mode https://shop.astropad.com/pages/meet-mac-to-mac-mode We are also launching a Kickstarter at the end of the month to add Windows support to Luna.
  - bjoli 6y ago
    Cool product! I am a Linux user, so that is not quite for me. But almost! I was just bummed that target display mode was removed in 2012. The last Mac I owned voluntarily had it, and the one I have now just sort of ended up in my hands. Now it is just an amazing display I don't really want to use since I can't run a proper OS on it without ruining the Mac os experience for my wife.
TekMol 6y ago
The final step is to use a VNC viewer app on your tablet to open the x11vnc session But is there a trustworthy one? Why would I allow all my information go to an app made by some company or individual I don't know and don't trust?
Fnoord 6y ago
If you start Steam, and have a client for Steam Play (e.g. TV or Android device with Steam Link) you can use that device as second monitor by alt tabbing out of Steam.
chx 6y ago
https://askubuntu.com/a/240571/8023 https://askubuntu.com/a/240571/8023 https://unix.stackexchange.com/a/235388/9452 https://unix.stackexchange.com/a/235388/9452
JansjoFromIkea 6y ago
I’ve always just used twomonusb, has just about worked and required very little configuration
- robotnikman 6y ago
  I took a look at the app on the play store, the horrible grammar doesn't exactly inspire confidence in it.
nicetryguy 6y ago
In this same vein, i use DroidCam and my phone as a high quality webcam. Full version is 5 bucks, money well spent!
- soylentcola 6y ago
  I started messing with that but found obs.ninja easier to use with better results. Then again, I already use OBS' virtual camera as the source in my conferences, if only for basic resizing and color correction of my mediocre webcam. Ended up not using it after a while because I didn't like the way the phone still gets pretty warm after an hour or two conference (same as DroidCam et al).

74 points by rodrigo975 6y ago

I needed a similar setup some time ago, and I was so frustrated by the Linux remote desktop open source solutions, that I ended up using Nomachine, which turned out to be very impressive. I'm mystified by the enormous gap between the open source solutions and Nomachine, both in the technical and usability areas. The open source solutions are sadly terrible; those who aren't convinced, just try Nomachine. It's puzzling because solutions like X2Go (which I found to be the most usable) rely on older NX protocol versions (v3 was open), but still, they have terrible performance. This means that in the last 10 years, there has been no virtually development in the open source remote desktop field.

FpUser 6y ago
Nomachine is my savior. I love it.
Fnoord 6y ago
Have you tried xrdp? Here's an example usage [1]. Your X server would run a sort of RDP emulation layer, and then any RDP client works. Obviously you'd tunnel it over a VPN or SSH. I haven't used NoMachine in like 10 years or so. Back in the days (~15 years ago), I used to run it on UltraSPARC machines running Debian and Gnome. It worked marvelous, even with a FOSS server (FreeNX IIRC). It even worked on the Nokia N-series! Although it sucked to run it on a Mac; you had to run a complete X server, which looked terrible (including the fonts). [1] https://github.com/deskor/xrdp https://github.com/deskor/xrdp
- high_priest 6y ago
  I've tried xRDP and it is still as terrible for fluid workstation interactions as is the whole RDP protocol. Sending only changing parts of the display is a great concept for data use reduction, but a quick x264 compression and simple input replication works much better on systems with 100Mb+ connections
- pizza234 6y ago
  Yes (specifically, the original distribution (https://github.com/neutrinolabs/xrdp https://github.com/neutrinolabs/xrdp) and the one provided in the repository of my o/s), and it fell flat on the usability side - gave me a blank screen after logging in. Gave up after an hour or two of attempts. X2Go worked straight out of the box, but it's very slow (on a 10 Mbit home wifi connection).
  - bleepblorp 6y ago
    Xrdp has horrendously bad documentation and installation scripts but it does mostly work after configuration. You have to manually edit /etc/xrdp/startwm.sh to make xrdp launch a desktop environment when it accepts a connection. If you don't do this, you'll get a blank screen or something non-useful, like a session with just one Xterm window and no desktop environment. Note that Linux does not support shifting sessions from the local keyboard, mouse & screen to remote access. Further, the major desktop environments don't support simultaneous sessions from the same user. With any of the remote access tools that don't simply take over the local screen and keyboard, if you have an active session on the physical screen, you won't be able to connect to it remotely, nor will you be able to start a new session remotely under the same login. you'll need to log out from the physical screen before attempting a remote connection. Finally, Xrdp clipboard sharing does not work with Linux clients.
derrick_jensen 6y ago
I also hate all open source Remote Desktop solutions, but I ended up using SPICE with Proxmox. Nothing else will forward audio and handling Remote Desktop at a virtualization level is the most reliable and flexible of everything else that I have tried. Only downside is that it doesn’t work with LXC containers, but that’s not a big problem considering only five or so machines need graphics. EDIT: another downside is lack of client support on iOS. I’d love to work on my iPad with a Magic Keyboard but no client exists that handles SPICE AFAIK.
papasamba 6y ago
Can you please explain how you setup nomachine to use your Android tablet as a second monitor

amelius 6y ago

I don't understand the need for more than one monitor. Just setup your desktop so you can switch virtual workspaces with a key combination. It's faster than turning your head.

goihoiholi 6y ago
That's your work style then. In many cases, I got the documentation on one screen, and my IDE on the other. Other times, it's more a distraction (i.e., whenever I just have mail or WhatsApp on the other) -- I'll turn off the second monitor then.
soreine 6y ago
Yes, most of the time you only need one screen, two screens mostly generate distractions. But I have noticed that switching workspaces is a context switch for your brain, just like passing through a door. You often forget what you were doing right after leaving a room for that reason. And when I truly need two different windows in a shared context, like some documentation in the browser and my code editor, it saves effort to have them truly side-by-side.
skocznymroczny 6y ago
I think it depends on the person. I also prefer one monitor. I'd rather have a big monitor than several screens. Also, I never really have more than one window open at a time. I don't mind switching between windows. But some of my coworkers swear by multiple screens and one app per screen. I think it's the same with tab management in the browser. I average 4-5 tabs open at a time, never really going above 10. But many of my friends are rolling with 80+ tabs at a time.
cbertoldi 6y ago
Another good example of why two monitors are useful is to have on one your favourite confenerence program with all the nice videos from your colleagues, and on the main one the page/board whatever you are discussing about. I.e. a Confluence page with collaborative editing on one monitor and Zoom/Teams on the second one.
blisterpeanuts 6y ago

dvfjsdhgfv 6y ago

"8-bit Buddhism" sounds even worse than 2-bit Islam. Honestly people, think a bit before choosing a name for your tech blog.

t-writescode 6y ago
I believe it’s a reference to the 8-fold path, and I thought it was quite creative: https://en.m.wikipedia.org/wiki/Noble_Eightfold_Path https://en.m.wikipedia.org/wiki/Noble_Eightfold_Path
- timbit42 6y ago
  Wouldn't it be more clever to call it 3-bit?
GavinMcG 6y ago
8-bit and two-bit have very different meanings and connotations.

ant6n 6y ago

Mmh. There are external, portable usb-c monitors, which are convenient because you can plug them into any usb-c laptop. But they are „dumb“, only work in connection with a laptop. I wonder whether there is one that can act as an Android tablet when not plugged in.

pella 6y ago
there is a hope: "Lenovo working on dual-purpose Android tablet and external monitor, ‘Yoga X’" https://9to5google.com/2020/07/10/lenovo-yoga-x-android-tablet-external-monitor/ https://9to5google.com/2020/07/10/lenovo-yoga-x-android-tabl...
chiefalchemist 6y ago
True. But I've looked at various small portable screens and they're rather expensive. The advantage of using something you already have is you save money and it's one less thing to carry. That aside, I struggle to understand why laptop to tablet still requires magic in 2020? Are manufacturers afraid of cannibalizing sales for one line to another?
- ant6n 6y ago
  Well I travel a fair amount for work and would like to have an external monitor for the work laptop, but also a personal tablet. With a 2-in-1 device I could solve both concerns without adding too much travel weight.
Fnoord 6y ago
I'm looking for one to combine with my MBP 2015 which has TB2/HDMI. However, even if ignoring that requirement, from what I can tell these all have terrible brightness. I, for one, cannot stand such.

reportgunner 6y ago

... or you could just use TeamViewer or any other screensharing software without all the hassle if you really think that using a RDP is a "second monitor".

arnoooooo 6y ago
This actually allows you to use both screens and move windows from one to the other. Not at all the same as just screensharing.

HMH 6y ago

This is quite similar to my latest project Weylus [1]. You still have to create the virtual output yourself but then you do not only get a second monitor but all the touch events are handled properly and you can even use a stylus/pen with pressure sensitivity. Additionally it also works on iOS/iPadOS. [1]: https://github.com/H-M-H/Weylus https://github.com/H-M-H/Weylus

_frkl 6y ago
Oh wow, pretty impressive. Have to try that out tomorrow!

nemacol 6y ago

This is neato but I would suggest you splurge for the USB monitor if you can. Still can't watch movies on it, but they are great little screens for the money. My main issue is, without a stand, they sit on the table and are uncomfortable to use for long periods. The ones I have used are VESA mountable though - so it is a problem with an easy solution.

zwieback 6y ago
My employer gave us a small budget to improve our WFH setup. I bought a USB "monitor" with a cover that folds back into a stand. I'm surprised how much I ended up liking this.

gambiting 6y ago

I bought a cheap £20 windows tablet from ebay(an old Tesco Connect 8 tablet), put windows 10 on it, and now I can seamlessly connect it as a second screen from anywhere, the windows "remote screen" feature is incredible for that. With 2 clicks it shows up as a regular secondary monitor that I can just drag things onto.

jonathanlydall 6y ago
I'm a big user of Remote Desktop on my Windows 10 computers, but am unaware of any "remote screen" feature. I did a quick internet search but couldn't really see any information about such a feature built into Windows. Could you tell me more about how you achieve this?
- soylentcola 6y ago
  I believe this is the Miracast feature that was common for a minute on some TVs and other devices but sort of fell by the wayside later on. You can mirror or extend your screen from one Win10 device to another Win10 device on the same network (assuming, of course, that it's not some sort of locked down or public wifi, etc.) Please correct me if I am wrong, as I've not used this function in probably a year or more.
  - gambiting 6y ago
    Yep, on one Windows 10 machine you need to go to Settings->Projection Settings, switch it on there, then from another Windows 10 machine you can simply press Win+P and select "connect to screen", then click on the other machine name. The only caveat is that both machines have to use Wi-Fi - it doesn't work over LAN at all. And yes, I believe it uses Miracast underneath.
    - 0xffff2 6y ago
      >both machines have to use Wi-Fi - it doesn't work over LAN at all This has to be one of the most baffling statements I've ever read on the internet. What on Earth could the possibly be doing that this is the case? Edit: Never mind. Another comment says that it's actually a feature of certain Intel WiFi chipsets, so it's not that you have to be using WiFi in general, it's that both devices have to be using specific Intel WiFi chips that support the feature.

kkapelon 6y ago

or you can simply use spacedesk.. https://spacedesk.net/ https://spacedesk.net/

Fnoord 6y ago
Caveat emptor: server runs on Windows only.

gbraad 6y ago

Use spacedesk or miracast if your device supports it

bjoli 6y ago

This is tangential to something I want to achieve: I have a 2016 iMac. Does anyone of you know if I can use that as a second display? Apple removed target display mode, which means the Mac with it's amazing screen is collecting dust. I have used it to ssh into my Linux machine and have it as my main terminal and documentation viewer machine using synergy, but that is tiresome.

mronge 6y ago
Yes! We built that into Luna Display: https://shop.astropad.com/pages/meet-mac-to-mac-mode https://shop.astropad.com/pages/meet-mac-to-mac-mode We are also launching a Kickstarter at the end of the month to add Windows support to Luna.
- bjoli 6y ago
  Cool product! I am a Linux user, so that is not quite for me. But almost! I was just bummed that target display mode was removed in 2012. The last Mac I owned voluntarily had it, and the one I have now just sort of ended up in my hands. Now it is just an amazing display I don't really want to use since I can't run a proper OS on it without ruining the Mac os experience for my wife.

TekMol 6y ago

The final step is to use a VNC viewer app on your tablet to open the x11vnc session But is there a trustworthy one? Why would I allow all my information go to an app made by some company or individual I don't know and don't trust?

Fnoord 6y ago

If you start Steam, and have a client for Steam Play (e.g. TV or Android device with Steam Link) you can use that device as second monitor by alt tabbing out of Steam.

chx 6y ago

https://askubuntu.com/a/240571/8023 https://askubuntu.com/a/240571/8023 https://unix.stackexchange.com/a/235388/9452 https://unix.stackexchange.com/a/235388/9452

JansjoFromIkea 6y ago

I’ve always just used twomonusb, has just about worked and required very little configuration

robotnikman 6y ago
I took a look at the app on the play store, the horrible grammar doesn't exactly inspire confidence in it.

nicetryguy 6y ago

In this same vein, i use DroidCam and my phone as a high quality webcam. Full version is 5 bucks, money well spent!

soylentcola 6y ago
I started messing with that but found obs.ninja easier to use with better results. Then again, I already use OBS' virtual camera as the source in my conferences, if only for basic resizing and color correction of my mediocre webcam. Ended up not using it after a while because I didn't like the way the phone still gets pretty warm after an hour or two conference (same as DroidCam et al).