Show HN: Slime OS – An open-source app launcher for RP2040 based devices

117 points by abeisgreat 15 hours ago

Hey all - this is the software part of my cyberdeck, called the Slimedeck Zero.

The Slimedeck Zero is based around this somewhat esoteric device called the PicoVision which is a super cool RP2040 (Raspberry Pi Pico) based device. It outputs relatively high-res video over HDMI while still being super fast to boot with low power consumption.

The PicoVision actually uses two RP2040 - one as a CPU and one as a GPU. This gives the CPU plenty of cycles to run bigger apps (and a heavy python stack) and lets the GPU handle some of the rendering and the complex timing HDMI requires. You can do this same thing on a single RP2040, but we get a lot of extra headroom with this double setup.

The other unique thing about the PicoVision is it has a physical double-buffer - two PSRAM chips which you manually swap between the CPU and GPU. This removes any possibility of screen tearing since you always know the buffer your CPU is writing to is not being used to generate the on-screen image.

For my cyberdeck, I took a PicoVision, hacked a QWERTY keyboard from a smart TV remote, added an expansion port, and hooked it all up to a big 5" 800x480 screen (interlaced up from 400x240 internal resolution).

I did a whole Slimedeck Zero build video ( https://www.youtube.com/watch?v=rnwPmoWMGqk ) over on my channel but I really hope Slime OS can have a life of it's own and fit onto multiple form-factors with an ecosystem of apps.

I've tried to make it easy and fun to write apps for. There's still a lot broken / missing / tbd but it's enough of a base that, personally, it already sparks that "programming is fun again" vibe so hopefully some other folks can enjoy it!

Right now it only runs on the PicoVision but there's no reason it couldn't run on RP2350s or other hardware - but for now I'm more interested in adding more input types (we're limited to the i2c TV remote keyboard I hacked together) and fleshing out the internal APIs so they're stable enough to make apps for it!