January 7, 2026
Weebs, wires, and wow
Project Patchouli: Open-source electromagnetic drawing tablet hardware
Fans lose it as DIY tablet brain works with common pens and even old iMacs
TLDR: Project Patchouli is an open-source “drawing tablet brain” that works with many pens and now ships thorough public docs. Fans are hyped by a wild demo retrofit, crack Touhou jokes, and plot reviving old iMacs—seeing this as a big win for DIY creators who want pro‑level pen input.
Open-source hardware just dropped a mic, and the comments are roaring. Project Patchouli promises a DIY “brain” for drawing tablets—built from off‑the‑shelf parts—that reads your pen with super low delay and works with lots of popular styluses. But the community is fixated on the vibes: one fan called the YouTube intro a perfect explainer and lost it at the finale where the creator slips the tech into a rugged Panasonic laptop—“watch it here.” Another spotted the soundtrack flex—yes, a Touhou rearrangement, “Original: ZUN”—and declared, “I wholeheartedly support weebs who create useful open-source electronics,” linking the Patchouli Knowledge meme energy straight to the PCB.
Beyond the anime jokes, makers are plotting real-world hacks. One commenter is already eyeing a 2009 iMac rescue with a Raspberry Pi brain transplant, while documentation stans cheer, “Very well written reverse engineering documents.” The general mood: giddy chaos meets serious cred. With code on GitLab, docs now live on Read the Docs (Jan 2025), and heavyweight open licenses (CC BY 4.0 for docs, CERN‑OHL‑S for hardware, GPLv3 for code), Patchouli screams “open all the way down.”
Timeline tea: started Jan 2024, hardware prototype landed by March, and it’s still under active development. Lead dev Yukidama plus a public Discord and NLnet’s NGI Zero sponsorship round out the lore. No real haters in sight—just a hot race to see who retrofits it first: old iMacs, tough laptops, or your next Franken‑tablet.
Key Points
- •Patchouli is an open-source EMR pen tablet hardware implementation for custom projects.
- •The design includes a coil array, RF front end using off-the-shelf parts, and DSP algorithms.
- •It aims for ultra-low-latency pen input and supports most commercial pens from multiple vendors.
- •Comprehensive documentation covers EMR mechanisms, circuits, signal processing, and pen protocols.
- •Licensing: CC BY 4.0 for docs/media, CERN-OHL-S for hardware, GPLv3 for code; sponsored by NLnet Foundation’s NGI Zero Core Fund.