The Tethered-cradle is a specially designed smartphone-cradle that can be tethered to a table-top. The Tethered-cradle platform is a portable-desktop format PC platform based on a Tethered-cradle.


A Tethered-cradle based portable-desktop PC platform can be constructed by fitting a smartphone inside a Tethered-cradle. The smartphone's touchscreen can then be used as a desktop user-input device, similar to a touchpad. The smartphone is connected to external screen, keyboard and other design-input accesories to complete the platform.

A native smartphone app is developed using a specially designed UI-library that enables it to run on the smartphone only in hand-held operation, or on the platform in desktop-mode.

Ergonomix is a MacOS developer-tool for designing apps for the Tethered-cradle platform. It works in conjunction with Xcode to produce an iOS app for the Tethered-cradle platform.


The planned platform has the following components:

  • A specially designed cradle for a smartphone.
    (166.6 mm x 90.6 mm x 12.3 mm, 200 gm).
  • A portable screen.
    HP E14 G4 FHD screen (321 mm x 210 mm x 15.2 mm, 640 gm).
  • A compact keyboard.
    Kensington KB435-EQ keyboard (318 mm x 125 mm x 19 mm, 420 gm).


Packaging dimensions (containing box, internal volume):
361 mm x 250 mm x 40 mm. (Macbook Air 15": 340.4 mm x 237.6 mm x 11.5 mm).

Package weight (bag of parts):
1260 gm. (Macbook Air 15: 1510 gm).


The planned platform could be laid out as illustrated below:


Some packaging considerations are illustrated below:




A smartphone is designed to be used as a hand-held device typically in portrait mode. In order to use its touchscreen as a desktop input device, the smartphone needs to be secured (in an immovable way) to a table-top.

For this purpose, we are designing a cradle. When placed inside this cradle, the smartphone's touchscreen can be used as an input device similar to a touchpad. This helps simplify the design of an app for dual-use -- smartphone-only or inside this platform.

The cradle could be placed anywhere on a table-top and some mechanical controls will be provided to adjust its planar orientation relative to a table's surface.

Dimensions: 166.6 mm x 90.6 mm x 12.3 mm.
Weight: 200 gm.




This is a 14" FHD (1920x1080) portable screen. It has a small built-in battery and a well designed hinge that folds open to a 78 deg screen-angle. 2 USB-C input ports for charging or display data. We use a small powerbank (such as Xiaomi 4900 mAh) to keep the screen charged.

Dimensions: 321 mm x 210 mm x 15.2 mm.
Weight: 640 gm.




This is a lightweight, compact form-factor keyboard. It connects wirelessly over Bluetooth and has a rechargeable battery.

Dimensions: 318 mm x 125 mm x 19 mm.
Weight: 420 gm.




Apple's A17 pro SOC contains a 3.78 GHz ARM ISA based microprocessor, a 6-core graphics engine and a 6.4GHz DDR4 memory interface. It's a well designed low power SOC that can easily be used in a desktop design environment. It can drive a 4k screen at 30Hz and has enough processing power for graphics intensive applications (that have high computational requirements).





Qualcomms's SnapDragon 8 SOC.