EngiPad

back at it with another project :3
this time a quick one!
(dates are again in mm/dd/yy cuz 🦅)

6/21/25 - started planning and designing in KiCad

we locking in for this one 🗣️🗣️🔥

For this Hackpad, I plan to base it off of the TF2 Engineer's Construction PDA, which has 8 switches and a rocker switch.

Looking at the model, the macropad can be split into two halves with the split going down the dark grey, with the PCB and electronics on the bottom half and the rest of the case going on top.

After I got the general plan down, I started to design the PCB in KiCad, starting with the schematic. I first considered doing a matrix-style wiring for the switches, but then settled on doing direct wiring since the Hackpad microcontroller has enough GPIO to support 8 switches and LEDs and the fact that matrix wiring requires diodes which take up space on the PCB.
I also decided to add on an OLED screen to the macropad, putting the OLED in a slot inside the PDA's screen. I originally planned not to do this idea since the OLED didn't have any screw holes, but then I was inspired by samliu's solution by having a slot in their macropad case, as seen in their Squarepad's CAD.

After I got the schematic, I started to work on the PCB design, mirroring the 3x3 grid of the Engineer's PDA with the 8th key taking up twice the space and adding RGB lights between the switches. I considered having the PCB extend throughout the macropad, but found it easier to place the RP2040 going to the side to compact the PCB below 100mm x 100mm in order to save money.
I also threw in some silkscreen art, making a TF2 inspired graphic for the front and a Highway backside, as well as a lanyard hole for extra PCBs!

note: i disabled the silkscreen in the PCB view since it made the board look very cluttered lol

I made the backside with Figma, using the frame technique I learned from the Highway Figma magazine to place and design my back silkscreen (and is by far my favorite pcb made yet :3)

I used an orthographic screenshot of the PCB's backside and used Figma to draw out shapes to put on the silkscreen! The graphic was made in black and white since it's the easiest format for KiCad's image converter to work with

time spent: 6 hours planning, designing PCB, and making art

6/22/25 - CAD time

After finishing my PCB, I started working on the case. While I could lazily take the game files for the PDA and port them into a model, I figured that ripping and using the exact models from the game would definitely NOT be allowed in Highway (plus the fact that it's lame and boring).
This left me with recreating the model in Fusion. I found a source online that had the original model for the PDA, and managed to import them into Blender to take pictures to aid in designing.

After a while, I finished most the CAD for the case. I split the case apart into the two shells, as detailed above, as well as splitting the trapezoidal screen part thingy into it's own section.

To mount the OLED in the screen section, I made two halves of the PDA's screen and sandwiched the OLED in between those two halves, with the headers poking out to connect to the PCB. The two halves are then slotted into the main shell for the screen, with the back side of one of the halves having a ledge for easy gluing.
I initially thought of using some tiny screws to mount the two halves, but was soon shut down due to the screws being too big for this scale and my printer not having that level of precision, especially at an angle.

The two case halves are mounted with the PCB in a sandwich style mounting, with the PCB in between of the screw holes in the case shells. The case halves also have a small lip where they can interlock to improve alignment and ease of building, which is used between the top shell and the screen section.

For the rocker switch, I used a 11.5mm wide hole to put my own toggle switch in (the metal lever one). I did find an actual rocker switch like the one in-game, but it was too large for my scale. I aimed to be as game-accurate for this CAD as possible, but using an actual switch was honestly too cool to pass up in my opinion.

However, for people who don't have a cool metal switch, I also made an alternate version of the screen shell with a rocker switch. (unfunctional though, sorry)

Speaking of being game-accurate, I noticed that the keycaps on the actual PDA model weren't perfectly square, but more like octogons in a way. This led to me designing my own custom keycaps, modeling them after the buttons on the Engineer's PDA.

time: 6 hours cadding