FunKey Zero
The FunKey Zero was a prototype keychain emulator console created by the FunKey Team in 2018. Designed and built to test the components that would later be used in the FunKey S, the FunKey Zero had a horizontal form factor akin to the original Game Boy Advance, rather than the GBA SP inspired clamshell designs of the team's prior and subsequent systems. While the FunKey Zero was only ever designed to be a non-commercial prototype, the FunKey Team, as with their prior Keymu system, released the FunKey Zero schematics so that others could recreate it with the same components.
Development
Following the popularity of their June 2017 Keymu showcase video and the subsequent requests to make the device available for purchase, the FunKey Team decided to design an improved version of the system that would have improved components, be more compact, and be mass-producible. To do this, Vicent and Michel brought the third member onto the team, David, whose previous experience with watches would help them make the device more compact. In designing an improved model of the Keymu, however, the team decided to first create the FunKey Zero, an intermediate prototype device that would allow the FunKey Team to test and adjust electronic components before designing a final clamshell system in which to house them.
Specifications
Due to its integration of the screen and controls into the same shell rather than two as with the Keymu and FunKey S, the FunKey Zero is both wider and thinner than the other FunKey Team systems. Due to the 2017 discontinuation of the Intel Edison, the computer-on-module that the Keymu had used, an ARM Cortex-A7 with 64 MB of RAM was used instead. To replace the Intel Edison's built-in eMMC storage, a microSD card reader was integrated into the FunKey Zero, allowing a maximum storage capacity of 128 GB. While the screen used in the FunKey Zero had similar dimensions to that of its predecessor at 1.54 inches (39.1 mm) and still only refreshed at a rate of 20 FPS, its use of LCD IPS technology instead of OLED, in addition to a 240x240 rather than 128x128 resolution, made it substantially different. As the system was a prototype for the later FunKey S much of the hardware is the same between the two, however, differences include the FunKey Zero's inclusion of a headphone jack and its lack of a battery, Menu button, and the later improvements that allowed the FunKey S to attain a significantly higher refresh rate of 50 FPS.
Comparison
Differences between the Keymu and the later FunKey branded systems include the use of the Intel Edison's built-in eMMC memory for data storage rather than a microSD card, the lack of a speaker in the original prototype (though its open sourced specifications allowed for the inclusion of one), a lower maximum resolution of 128 by 128 pixels, smaller buttons, and a lower-capacity 220 mAh battery. Features only implemented in the later FunKey S and not in the Keymu or FunKey Zero include a magnetic "sleep-mode" mechanism, a protective glass layer above the display, a Menu button, 50 rather than 20 FPS, no screen tearing, and an improved hinge.
Table
| Name | Keymu | FunKey Zero | FunKey S | |
|---|---|---|---|---|
| Image |  |
 |
 | |
| Dimensions | 1.65" x 1.81" x 0.67" 42 x 46 x 17 mm |
~3.45" x ~1.79" x ~0.32" ~87.6 x ~45.5 x ~8.1 mm |
1.67" x 1.75" x 0.54" 42.5 x 44.5 x 13.8 mm | |
| Mass | N/A | 1 oz 30 g | ||
| Display | 1.5" (38.1 mm) 128x128 OLED | 1.54" (39.1 mm) 240x240 LCD IPS | ||
| Processor | Atom 2-Core @ 500 MHz | ARM Cortex-A7 @ 1.2 GHz | ||
| RAM | 1 GB (LPDDR3) | 64 MB (DDR2) | ||
| Refresh rate | 20 FPS | 50 FPS | ||
| Maximum storage | 4 GB (eMMC) | 2 TB (microSD) | ||
| Audio | ∅11.7 mm mono at 700 mW (missing from the initial prototype) |
∅10 mm mono at 500 mW | ∅10 mm mono at 500 mW | |
| Headphone jack | ||||
| Battery | 220 mAh lithium-ion | None (prototype) | 410 mAh lithium-ion | |
