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1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errorsPenk Chen’s Penkesu is a DIY handheld computer that folds open like a gadget pencil case. It pairs a Raspberry Pi Zero 2 W with a 7.9-inch, 1280 × 400 touchscreen and a 48-key ortholinear mechanical keyboard. Chen has published the design files and build instructions, but Penkesu is a maker project—not a commercially available PC or kit.
What is the Penkesu?
Penkesu is a homebrew, retro-style handheld computer designed by Penk Chen. Its fold-open, 3D-printed enclosure, widescreen display and compact mechanical keyboard give it the look of a small portable writing computer. The name draws on the Japanese word for pencil case: Chen told Raspberry Pi Magazine that gadget pencil cases were popular among children in Asia in the 1990s, an influence behind the design.
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The computer is built around a Raspberry Pi Zero 2 W. The display measures 7.9 inches diagonally and has a 1280 × 400 resolution, while the keyboard has 48 keys in a grid-like ortholinear layout. The combination is designed to fold into a compact package rather than resemble a conventional laptop.
What is inside the published build?
Chen’s repository lists the following components for the documented build. Parts and compatibility should be checked against the current files and supplier listings before ordering.
#1 Best Overall
- The PocketTerm35 is a handheld computer designed specifically for the Raspberry Pi 4B and Pi 5.
- It provides a complete Linux desktop experience, enabling you to enter commands, run development tools, or execute daily computing tasks directly in the terminal at any time.
- Features a compact 93.5 × 168.5 × 37 mm design, equipped with a 3.5inch 640 × 480 optical bonding touch display. Portable and lightweight, it is an ideal tool for geeks, developers, and electronics enthusiasts.
- Suitable for terminal operations, command-line input,and graphical interface browsing
- Supports seamless switching between Batt and external power,enhancing system reliability. Supports handheld gaming, compatible with the RetroPie system
| Part of the build | Published components |
|---|---|
| Computer | Raspberry Pi Zero 2 W |
| Display and connection | Waveshare 7.9-inch capacitive touchscreen; Adafruit DIY HDMI cable parts, including a right-angle adapter, mini HDMI adapter and 20 cm ribbon cable |
| Power | 3.7 V 606090 LiPo battery or a similar-size battery; Adafruit PowerBoost 1000C |
| Keyboard | Kailh low-profile Choc V1 switches, MBK Choc low-profile keycaps, 1N4148 diodes, Arduino Pro Micro and a custom keyboard PCB |
| Enclosure and fasteners | 3D-printed chassis, Game Boy Advance SP replacement hinges, M2 × 6 mm screws and heat-set threaded inserts |
The repository provides keyboard PCB Gerber files and QMK firmware, as well as STL and STEP files for the enclosure. Chen calls the keyboard Koda. He adapted its layout for his own needs and to resemble the Planck keyboard; the repository also says builders can adapt the case for another 40% keyboard by editing the STEP file and resizing the keyboard compartment. That allowance is a design option, not a tested comparison of alternate keyboards.
Why the screen, hinges and case matter
The wide, shallow screen and keyboard shape the enclosure. The 20 cm ribbon HDMI cable routes through the hinge cover, while repurposed Game Boy Advance SP hinges let the screen fold open without a bulky hinge assembly. The published build guide describes gluing the hinges into the chassis, fitting heat-set inserts, routing the display cable, wiring the battery and PowerBoost, connecting the display and keyboard to the Pi, and fastening the components.
Rank #2
- RASPBERRY PI CM5 COMPATIBLE: Designed to work seamlessly with the Raspberry Pi Compute Module 5, offering a powerful handheld computing experience. CM5 not included.
- 4-INCH TOUCHSCREEN DISPLAY: Features a responsive 4" touchscreen for intuitive navigation and interaction, making it ideal for portable projects and on-the-go use.
- NVME SSD SLOT: Equipped with an NVMe SSD slot for fast, expandable storage, allowing you to run demanding applications and store large files with ease.
- DUAL USB 3.0 PORTS: Includes two USB 3.0 ports for high-speed data transfer and connectivity with a wide range of peripherals and accessories.
- ALUMINUM CASE WITH FULL QWERTY KEYBOARD: Built with a durable aluminum enclosure and a physical QWERTY keyboard, combining sturdy construction with convenient text input.
Balance is another practical design issue: Chen told Raspberry Pi Magazine that the screen made the open device top-heavy. The repository describes gluing a thin metal sheet into the base as a counterweight to help the computer remain stable when open.
“Ortholinear” means the keys are arranged in aligned rows and columns, like a grid. That layout is a defining feature of the Koda keyboard, rather than a conventional staggered typewriter-style arrangement.
Rank #3
- 1. ClockworkPi v3.14 mainboard revision 5, (Optional) Raspberry Pi CM4 104000 lite (ARM Cortex-A72 quad-core, 4GB LPDDR4, WIFI 2.4 GHz, 5.0 GHz IEEE 802.11 b/g/n/ac wireless + Bluetooth 5.0, BLE) Adapter for RaspberryPi CM4 computing module to the mainboard.
- 2. WIFI gain antenna for CM4 computing module. Ext. module. Standard HD 720p 5.0-inch IPS screen
- 3. Clockwork ultra-portable QWERTY Backlit keyboard
- 4. Dual speaker, Shells and bracket system & 2.5mm Hex key
- 5. 32GB high-speed TF-card with clockworkOS*
How to approach a Penkesu build
- Review the current project files. Start with Chen’s Penkesu repository for the bill of materials, build guide, enclosure models, PCB Gerbers and firmware. Confirm that the files and component references match the version you intend to build.
- Check component fit before purchasing. The screen, keyboard, hinge hardware, ribbon cable, battery and power board all need to fit the printed enclosure and connect as intended. If substituting a 40% keyboard, account for the repository’s instruction to edit the STEP file and resize its compartment.
- Fabricate and assemble the enclosure. The guide covers the printed chassis, glued hinges, M2 heat-set inserts, cable routing and component fastening. Take care with the hinge path so the ribbon cable can pass through without being pinched.
- Wire and connect the electronics. The published design connects the Pi, display, keyboard, battery and PowerBoost. Follow the project’s wiring instructions and verify component compatibility rather than assuming a similarly sized part is electrically interchangeable.
- Test the open device’s stability. The project describes a thin metal sheet glued into the base to counterbalance the display. Treat that as a documented design measure, not a quantified performance guarantee.
Is Penkesu a product you can buy?
No commercial kit or mass-produced Penkesu is established by the project’s published information. Chen said the plans were released so interested readers could build the device, with no immediate plan to sell kits or make it mass-producible. The project is best understood as a DIY design with published files, so the builder sources parts and handles fabrication and assembly.
The repository says its files are licensed under MIT. It separately credits the original Koda keyboard design to larrbo under CC BY-NC-SA 4.0; those are distinct licensing statements, and neither should be generalized to every third-party component or design referenced by the project.
Rank #4
- The PocketTerm35 is a handheld computer designed specifically for the Raspberry Pi 4B and Pi 5.
- It provides a complete Linux desktop experience, enabling you to enter commands, run development tools, or execute daily computing tasks directly in the terminal at any time.
- Features a compact 93.5 × 168.5 × 37 mm design, equipped with a 3.5inch 640 × 480 optical bonding touch display. Portable and lightweight, it is an ideal tool for geeks, developers, and electronics enthusiasts.
- Suitable for terminal operations, command-line input,and graphical interface browsing
- Supports seamless switching between Batt and external power,enhancing system reliability. Supports handheld gaming, compatible with the RetroPie system
What is not established about the build
The project materials and cited coverage do not establish a current total build cost, battery runtime, benchmark results or present-day parts availability. They also do not provide comparative test results for alternate screens, computers, keyboards, power arrangements, fabrication methods or hinge designs. Treat Penkesu as a documented design to adapt carefully, not as a product with verified retail specifications or performance figures.
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Best Value
- 1. Barebones Kit for Raspberry Pi CM4 – Made for users who want to add their own Raspberry Pi CM4 module to a portable handheld Linux computer kit.
- 2. Multiple Configurations Available – Choose from with WiFi-only or WiFi + 4G LTE connectivity options.
- 3. 5 Inch QWERTY Handheld Design – Features a 5 inch IPS display, compact QWERTY keyboard, mini trackball, speakers, and handheld cyberdeck-style layout.
- 4. ClockworkPi v3.14 Rev 5 Mainboard – Uses the ClockworkPi v3.14 revision 5 mainboard platform with CM4 adapter support for Raspberry Pi CM4 users.
- Important Package Note – Raspberry Pi CM4 module, 18650 batteries, TF card, SIM card, and cellular service plan are not included.
Sources
- Penk Chen’s Penkesu repository — parts list, files, assembly guide, firmware and license information.
- Raspberry Pi Magazine’s Penkesu feature — design context and comments attributed to Chen.
- Raspberry Pi’s feature on the handheld — hardware overview and explanation of the ortholinear layout.
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