1. Hardware
1. Sound & Power Switch
2. Keyboard
3. Wired Connections
1. Power
2. Keyboard & Sound
2. Software
1. Installing the distribution
2. Setting up the Screen
3. Audio Setup
3. 3D Printed Case
4. Going Further

I recently got hooked by the idea of building an ultraportable Linux computer that can be used for several purposes like quick network troubleshoot & maintenance, portable workstation, LIDAR solution, retrogaming device.

Hyper Keyboard PI is a fantastic kit made by Jinson that exploit the full potential of the Raspberry PI by wrapping up keyboard, gamepad and speakers in a pocket format for around ¥ 8,800 (~68 euros).

Hardware

The kit contains 4 PCBs and microcontroler for the keyboard. Note that the Pomoroni's Hyper Pixel screen is not included in the kit and you should probably purchase one.

Sound & Power Switch

The PCB include support for the TDA1308, an integrated class-AB stereo headphone driver wich is a nice choice for portable digital audio applications since his low power supply consumption & audio distortion.

The design override also the use of the PI's USB alimentation and provide a new connection that will be used for the rest of the circuit

Keyboard

The keyboard is based on HT82K629A USB 1.1 keyboard encoder. PCB provides Qwerty layout so remmaping is needed if it's not your current layout.

Wired Connections

Power

Once you plugged the screen, you are able to weld the 5V GPIO pin on the back of the PI.

Keyboard & Sound

Sound & Keyboard don't use classical GPIO pins but exploit the Test Ports of the raspberry wich can be welded with our PCB:

• PP44 & PP45 are used for sound.
• PP25 & PP26 are used for keyboard.

Software

Installing the distribution

I made the choice of installing Arch, it makes a good choice for our setup since it's lightweight and have an nice ARM packages support.

Installation guide here for ARMv7.

Setting up the Screen

Screen setup need specifics Devices Tree kernel blobs that are available on Github.

sudo pacman -S git

cd /tmp
git clone https://github.com/pimoroni/hyperpixel4 -b pi3
cd hyperpixel4

sudo ./install.sh

# landscape, power/HDMI on bottom
/sbin/hyperpixel4-rotate left

reboot

Audio Setup

The kernel config should be updated before using ALSA.

echo "device_tree_param=audio=on" >> /boot/config.txt
reboot

3D Printed Case

A fancy gameboy like 3D Printable case is available on kichitaro's Booth.pm page.

Note that the case replace the Back PCB cover shipped in the kit. Some additional screws are needed to finalize the case assembly.

Going Further

Some idea to add in the future:

• 4G Network support
• LIDAR Support?