Using Expresii Watercolor with Sonar Pen via SpaceDesk

The Sonar Pen

The SonarPen was launched through Kickstarter in 2018.  It was primarily designed for iOS and Android smartphones and tablets as a cheap alternative to the expensive styli like the Apple Pencil. 

We actually have been in contact with  SonarPen's creator Elton Leung since 2018.   We were hoping they can add Windows support ever since. To date, there's still no Windows driver but thanks to the support from SpaceDesk, we can now use it for Windows apps too.

The Sonar Pen

Sonar Pen with a disk tip and a side button

We also wished it supports tilt sensing but we're not sure if that would ever happen.

The SpaceDesk app

SpaceDesk is a software tool that allows a host machine to use other machines like tablets as its monitors.  Their ability to build a monitor wall is amazing. Recently they added support for relaying pen input too, so it's possible to use SpaceDesk as a wireless Pen Display. With SpaceDesk, we're now able to use SonarPen on Windows apps, including our Expresii that features beautiful organic digital watercolor. 

Previously, we tried   Easy Canvas Pro  (US$5 / year) and   SuperDisplay   (US$10 one time)   for Pen-Display application. Currently, we think SuperDisplay  gives the best performance among the three.  SuperDisplay  does support pen tilt, which is quite important for our app Expresii.   SpaceDesk doesn't support pen tilt nor  multi-touch gestures yet. SpaceDesk is currently free to use, while they also offer a Business license. Our current recommendation is still   SuperDisplay, which is the fastest, the most feature-complete and is inexpensive.   We look forward to SuperDisplay supporting the SonarPen.

2021.05.06 Update:  you can use USB tethering for faster connection on SpaceDesk.

What can still be added: ​It'd be great  if any of these programs can relay accelerometer/orientation sensor  readings and act as a G-Sensor  of Windows tablets so that we can directly control paper tilt in Expresii to direct the paint flow. Using other apps like  Sensor stream IMU+GPS  alongside is no good, as only one  app can be in the foreground and nowadays smartphones would have background apps dormant  after a few moments. We've tried putting the app in Battery Saving Exception or disable Battery  Optimization (on Android 9) but to no vain.

In the above video, we also show the new features of  Brush Tilt Control Pad    and   Auto Settle Timer:

Brush Tilt Control Pad

This is specifically added for the case of using SonarPen via SpaceDesk, since the pen is not tilt-sensitive and that SpaceDesk doesn't support pen tilt yet.  For other pens, usually their barrel (side) button can be re-assigned by the user, and we can use it as Mouse Right Button to adjust the brush tilt. However, in SpaceDesk, SonarPen's side button is fixed to toggle between touch and pen input. Our answer to this is the Brush Tilt Control Pad .  It acts like a virtual trackpad on screen - you can  use your finger, mouse or pen to drag on it to adjust the brush tilt.

​Paint Settle Timer

You can now stack paint in the same layer by settling paint. We've also added a timer for auto-settling. You can try these new features in a beta version of Expresii, which you can enable by selecting beta option in the System>Advanced tab. Please let us know how you like them.

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Selecting Beta mode