Using the MacBook with an eInk Tablet as an External Display

Using an eInk display as an external screen reduces eye strain and is well readable in direct sunlight. How do you connect the Onyx Boox Tab Ultra to a MacBook Air? Let's explore various methods like AirDroid Cast and Duet Display, alongside a more economical and effective solution involving a USB Capture Device. Find out the details in this article and video.

November 2023

Using the Boox Tab Ultra as an external screen for the MacBook Air. (Photo: Marin Balabanov)

Reading devices like the Kindle and the Pocketbook are pretty popular with voracious readers because they do not strain the eyes as much as a traditional LCD screen. The eInk display is also a lot more energy efficient, allowing you to read for days on end without recharging the battery. The downside is that the refresh rate is relatively slow, so you can only really use it for reading. And eReaders are single-purpose devices, so you avoid distractions from messaging and social media apps and can fully focus on the reading experience.

Android eInk Tablets

In the last few years, a new type of tablet has emerged that uses an eInk display. They are fully featured Android tablets that support most apps on the Google Play store. They have been gaining popularity, particularly for users interested in reading and note-taking. The eInk technology offers a paper-like view, which is easier on the eyes and ideal for long reading or writing sessions. A popular series of devices is the Onyx Boox range of tablets.

Onyx Boox tablets are available in a range of sizes, from 7.8" to 13.3". They are ideal for reading and note-taking, and are popular with students and academics. They are also popular with people who like to read outdoors, as the eInk display is easy to read in bright sunlight.

Using an eInk Tablet as an External Display

While the devices are really good and useful in their own right, they can also be used as an external display for a laptop. This provides computer with a portable display to extend the machine's desktop. Additionally, the eInk display is perfectly readable in direct sunlight. You can use solutions for Windows devices, e.g. Spacedesk and Samsung Second Screen. Unfortunately, they are not usable with a Mac.

Connecting with a MacBook

AirDroid Cast works with the Mac, and it is free of charge if you only want to connect an Android tablet with a USB cable. Unfortunately, this does not work with the Boox Tab Ultra because it requires Developer Mode on the Android tablet. The Boox devices have the settings switch to activate developer mode obscured from regular users. There are applications that you can side-load to make Developer Mode visible. But the sources for these apps are very dubious. Of course, if you are willing to pay the subscription fee for AirDroid Cast, you can connect wirelessly without needing Developer Mode. (Quick Update: A user on Reddit let me know that you need to pay for AirDroid Cast even if you want to use it with a cable connection.)

There is another option that works great in principle: Duet Display. I promise this will be our last setback before we actually have some good news! The bad news is that Duet Display requires quite an expensive subscription to unlock any of its features.

So, what can we do? Well, there is a solution that works with the Boox Tab Ultra, and it is free of charge.

The connectors and adapters needed. (Photo: Marin Balabanov)

This is what you need in addition to the Boox Tab Ultra and a MacBook:

• USB-C to HDMI adapter
• USB Capture Device
• HDMI cable
• USB-A to USB-A Adapter (for the USB Capture Device)

You can use the HDMI cable to connect your MacBook with the Boox Tab Ultra. You can't do this directly because the Boox Tab Ultra only has a USB-C port and not an HDMI port. You will need a USB Capture Device that has an HDMI port on one end and connects to the USB-C port of the Boox Tab Ultra. You can get one for about twenty Dollars or Euros on Amazon. The MacBook has a USB-C port, so you will need a USB-C to HDMI adapter. You can also get one for a few dollars on Amazon. Once you have the cable and the adapter, you can connect the MacBook to the Boox Tab Ultra.

The Boox Tab Ultra will not automatically detect the USB Capture Device. You will need an app for that. There are many, but one good option is USB Camera. It is free of charge, and it works well with the Boox Tab Ultra. Once you have installed the app, you can connect the USB Capture Device to the Boox Tab Ultra and it will detect it. The app will display the Mac's screen and use the Boox Tab Ultra as an external display for the MacBook.

There are two downsides to this solution.

1. The free version of the app is ad-supported, so an ad banner will be visible on the Tab Ultra's screen at all times. It does not impede the functionality, but it can be distracting. You can purchase the "Pro" version of the app for a few dollars. This is a bargain compared to the subscription fees for Duet Display and AirDroid Cast.
2. The app uses the USB Capture Device to translate the HDMI signal. This introduces an ever-so-slight lag. To be fair, is comparable to using Duet Display or AirDroid wirelessly and it is not noticeable because the eInk display has it's own lag due to the low refresh rate. The refresh rate is not really good enough for video.

A quick video with instructions on how to use the Boox Tab Ultra with a MacBook Air (direct link to Youtube)

Alternative: VNC

The last option is a bit of a hack, but it works. The solution is to use the Boox Tab Ultra as a VNC server and connect to it from the Mac using a VNC client. The VNC client is already installed on the Mac, so we only need to install the VNC server on the Boox Tab Ultra. There are a number of VNC servers available on the Google Play store, but the one that works best is VNC Viewer. It is free of charge, and it works well with the Boox Tab Ultra.

As a final note I'd be remiss to mention that there are also dedicated eInk monitors available (e.g. from Dasung), but they are quite expensive, and they can only be used as external screens and nothing else.

eInk Futures

eInk displays are getting better and better. They are now available in color, and they are getting faster. Onyx has Boox Tab Ultra C and Boox Tab C Pro color models. The refresh rate is still not good enough for video, but it is good enough for many other uses e.g. writing, researching, coding. The color models are also more expensive than the black and white models. But they are still cheaper than the dedicated eInk monitors. So, if you are interested in an eInk display, you should definitely consider the color models. They are a bit more expensive, but they are more versatile, and they are future-proof. The black and white models are still a good option if you are on a budget.

Whether it's for avid readers, diligent students, or tech enthusiasts, the integrating an eInk tablet as an external display with your MacBook opens up new possibilities for eye-friendly computing. I - for one - look forward to the colorful future of eInk technology as a small yet significant steps towards a more versatile and enjoyable digital experience.