Chonky Palmtop

It struck me to put this together when I saw how close in size the 7" touchscreen, battery cells, and crkbd folded vertically that I had sitting on my desk were. And I I needed a build that was actually functional for normal computer stuff, so this seemed like a good idea.

It turns out that this is a pretty functional setup. The 7" display is okay as long as I fullscreen stuff. Alt+F11 works with a lot of stuff so far. I've been able to use onshape cad in firefox. It's a little slow, but works as long as firefox doesn't have issues with gfx acceleration. Console stuff and web browsing are great!

Status

The current to-do list:

• Figure out why gfx acceleration is broken for firefox!
• Look into voltage warning wirining to gpio for the psu... not super useful since I don't have a way to actually switch the psu off.
• Rework the lower left hinge bracket with integrated wire protection to match the lid.
• Integrated pwnagotchi with power controls via gpio. Sort of a separate project...

Keyboard

The keyboard is a Corne Classic with Miryoku Firmware. It has mouse emulation that works surprisingly well when not using a usb mouse.

Firmware

Using the Miryoku Firmware found here: https://github.com/manna-harbour/miryoku

Pivot Geometry

One corner of each keyboard half moves up the center of the chassis on a straight path. The other povot point follows some other path to acheive the desired total rotation, and we have some control over how it gets there by curving the path it follows.

We can figure out the starting and ending points of the second pivot by projecting it's location in the closed and open positions, and then drawing a path between them. See the yellow lines in the cad sketch below. We use a path that first curves down to help us dip the keyboard around the hinges that hold the display.

First draft of the sliders:

Power System

The PSU/Charge controller is an Amp Ripper 3k, which seems to work well satisfying the Pi 4 and display without low voltage warnings. It can be wired so an external switch, and has a signal pin to indicate low, but doesn't seem to actually be able to disconnect your system from the battery if voltage gets too low, so you should include some additional low voltage protection. It charges at up to 3a via USB-c port:

This build has two li-ion pouch cells wired in parallel, each separatly fused for 10a for short curcuit protection. There's an XT60 connection on the side in case I want to rig up a fast-charge. The li-on cells used here aren't the best choice for energy density, but they can fast charge - limited only by the gauge of the wire I connect tehm with, and if I change them later, there's room in the battery box for a bunch of 18650 cells instead.

There is a switch and a voltage button on the right side of the screen to turn it on and check the battery level:

USB Wiring

There is a usb hub inside the lid that'r wired with ground, D+, D-, directly to the usb pins on one of the pi ports. Posotive power comes directly from the psu. The ground and data wires are bundled with heat shrink to keep them paralle and close so they have the correct impedance for the usb connection. I tried with them loose and the connection didn't work.

Before I added a ground wire and bundled them:

And another similar build:

Chassis Details

Wiring for the front facing ouchscreen controls:

Display Keeps the keyboard closed when folded:

Hinges and stuff:

Materials List

• Printed parts - See the "Stl Files" derectory.
• Pi 4 (4gb minimum)
• Ampripper 3k PSU/Charger: https://www.tindie.com/products/kickstart_design/ampripper-3000-5v-3a-lipo-battery-charger/
• Chonker spim08hp cells:https://batteryhookup.com/products/2x-spim08hp-3-7v-8ah-cells-with-threaded-insert
• 7" Touchscreen: https://www.amazon.com/gp/product/B07L6WT77H/
• USB Hub: https://www.amazon.com/gp/product/B00L2442H0/
• Hinges: https://www.amazon.com/gp/product/B07GX8LQCX/
• Bolt and Nut Kit: https://www.amazon.com/gp/product/B093FWLJZC/
• 1/4" Screws: https://www.amazon.com/gp/product/B00GDYNHL6/
• 3/8" Screws: https://www.amazon.com/gp/product/B00GDYNJNM/
• Crkbt Classic PCB: https://www.littlekeyboards.com/collections/corne-pcb-kits/products/crkbd-classic-essentials-kit
• Your choice of choc switches.
• Diodes
• mcu, e.g. pro micro or elite c
• Machine Pin Sockets for mcu: https://www.adafruit.com/product/3647, https://www.adafruit.com/product/3646
• Keycaps: https://www.littlekeyboards.com/collections/keycaps/products/mbk-choc-low-profile-keycaps
• 22 Gauge Silicon Wire: https://www.amazon.com/gp/product/B07T4SYVYG/
• 18 Gauge Silicon Wire: https://www.amazon.com/gp/product/B073RDBW7L/
• In-line Fuses: https://www.amazon.com/gp/product/B07ZTYN9DY/ (higher amperage would be better maybe) )
• XT60 Connector: https://www.amazon.com/gp/product/B01ETROGP4/
• Voltage Indicator: https://www.amazon.com/gp/product/B00YALUXH0/
• 6mm Tactile Buttons: https://www.adafruit.com/product/367
• 6mm Clear Top Buttons: https://www.adafruit.com/product/4183
• Switch: https://www.amazon.com/gp/product/B008CZIG3I/

Authors and acknowledgment

Thanks to the Cyberdeck Cafe Discord and the Cyberdeck Reddit for loads of inrpiration and collaboration!

License

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