For a project I am working on, I would really like to have a semi portable, large tablet. As of my writing this, there’s one 14.7″ (37cm) tablet, the Samsung Ultra, then a handful of 13″ devices such as those from Apple. On Aliexpress and from LG I can also find touch screen more-like-a-TVs in the 22 inch and 27 inch class, running Android, and on small wheeled stands. There aren’t many choices because, in general, people don’t want much bigger than about the size of a sheet of paper because anything else becomes uncomfortable to hold for an extended period of time. In my case, I want a touchscreen that I can use for a combination of data visualization and data entry, with a potential secondary use for entertainment – a semi-portable, tabletop interactive display, not something I plan to use while holding but would move from table to table.
Here is the recipe I’ve found for a semi decent tablet of large size:
- Portable Monitor, Touchscreen
- Must support USB-C for display and touchscreen
- Likely easiest if it has a second USB-C port for power, or else can do USB-C PD pass-through, or else has a built in battery. USB-C PD pass through would clean up the setup a little, but from what I have seen most of the best quality displays didn’t have these. Built in battery models often don’t share power to devices so a battery for the mini pc is likely necessary.
- Things to consider: screen brightness (500 nits recommended, 400 nits minimum), aspect ratio (16:10 better than 16:9 for tablet), contrast ratio (for deep blacks), resolution (4k is nice but 2.5K/QHD is probably fine). Choose size as desired, as or writing, 16″ seems to have the most choices.
- Should probably have a VESA mount (4 bolt holes in 75 mm spacing), but other types of mounting hardware may work
- Mini PC or SBC
- Must have a USB-C display port alt mode capable port!
- Often if a port is listed as USB 3.2 or greater it will support it, but not guaranteed, check to see if it lists display out for that port
- Thunderbolt is a safe bet, but pretty rare on the smallest of these mini pcs
- Must have a second USB-C PD power port (unless monitor and port with PD pass through)
- Must be a lower power system, ideally with an idle power <5W
- Must support a touch capable operating system. Linux, Android, Windows should work. MacOS seems to have very limited touchscreen support, although you can get a touchscreen monitor and go to an apple store and see if it will plug into a mac mini and work with touch (it probably will display but not touch).
- A handful of tablets and phones support display out with touch screen support (higher end Samsung devices especially, those with usb 3.2 and Dex). You might be able to find one with a broken screen but otherwise functioning and use as the compute.
- Some gaming handhelds (ala Nintendo Switch or Steam Deck) support USB-C output, with some companies making some very small ones.
- Some lower powered devices only support 1080p (Full HD) output for the display. Check if that resolution is too low for you.
- Must have a USB-C display port alt mode capable port!
- Power Bank(s)
- will probably want about 15W for display and 15W for mini pc
- will probably want at least 10,000 mah (which is around the battery size for most production tablets)
- 10,000 mah, dual output at 30W (hard to find this in a small size)
- or, 2 separate 5000 mah batteries (can find these in a small size, but would have to charge them separately)
- if using a monitor capable of USB-C PD passthrough, having a power bank with around 45-60W output rating may be necessary
- Right angle, high quality USB C cables (for display, make sure it is display out capable, USB 3.2 or 4.0 or thunderbolt rated)
- VESA stand or other display mount as needed
The setup is generally quite straightforward. Install the operating system on the mini pc if not already present. Power the mini pc and display from the appropriate power banks. Connect display and power ports. Once satisfied with the setup, either 3d print a bracket to attach to the VESA mount, or just duct tape or epoxy the parts to the display. Known issues: portrait to landscape rotation will have to be done manually in the OS. May want to set lower power settings in BIOS/OS for mini pc and in the display menu.
This project illustrates both the advantages and challenges of USB-C. It is nice to have one type of port that can do it all, but challenging to find exactly what protocols the port on each device actually supports.
Incidentally this is fairly similar to how how some stores/hotels/events use touchscreens for kiosks, although often those don’t have battery power. Some people also put together displays like this for their cars.
Here is a late 2024 suggestion for parts. There will likely be better/cheaper/more-available options at a later time or specific to your needs:
- 18 inch touch portable monitor (this one is rather on the cheaper end in build quality) or this
- N100 palm sized mini PC
- Portable VESA mount or simple VESA stand or a rotating one
- Right-angle Thunderbolt cable
- USB-C Power Bank (would likely need 2x of these for most arrangements) or one of something like this