I'll be presenting some of my latest work on Xous & Baochip with @Xobs at #39C3 on Day two, 11PM room One:

https://fahrplan.events.ccc.de/congress/2025/fahrplan/event/xous-a-pure-rust-rethink-of-the-embedded-operating-system

Hope to see you there!

For more on Baochip, checkout bluesky: https://bsky.app/profile/baochip.com or read the source at github: https://github.com/baochip/baochip-1x

The TL;DR is that Baochip is a "mostly-open" RTL SoC in 22nm TSMC, purpose-built for Xous and expressly packaged for IRIS inspection. It packs in five RISC-V CPU cores (one Vexriscv CPU at 350MHz, and four PicoRV's at 700MHz), 2MiB on-chip SRAM and 4MiB on-chip RRAM (basically FLASH).

I'm aiming to have the chip broadly available by early 2026. Right now I have first silicon. You can follow development & ask questions on the Baochip discord at https://discord.gg/yesbcPF9Xy

Sorry, no website yet - I suck at marketing - but hey, at least the source code is up!

Helped a friend rework a batch of boards with broken MEMS microphones. Took some images of the silicon membranes...first two are from broken samples, last two are from intact microphones. Our best guess is the CM used shop air to blow dust off the boards and destroyed the microphones with over-pressure.

MEMS devices are pretty neat to look at. Looks like this device is composed of a base silicon chip with a hexagonal silicon membrane suspended above, forming a moving mechanical element that can measure sound waves.

Just finished Cory Doctorow's latest novel, "Picks and Shovels" - what a thriller! Cory had me hanging on every word, blending retro-computing, romance, and rebellion into a masterfully spun tale.

Five stars, would recommend.

Here's a teardown on Formlabs' just-released Form 4:

https://www.bunniestudios.com/blog/2024/formlabs-form-4-teardown/

Always a fun learning experience taking apart their 3D printers!

The Form 4 is an LCD-based 3D printer with neat details like a metal core PCB, custom liquid crystal element, and a Raspberry Pi CM4 inside.

Here's how I stitch individual IRIS images together to create a full-chip composite using template matching and MSE cleanup:

https://www.bunniestudios.com/blog/2024/automated-stitching-of-chip-images/

This is the last post in my series of updates on the IRIS project. Thanks for reading!

Now, back to my happy place, hiding in my lab hacking on stuff~~ ​

"Beware programmers that carry screwdrivers" -- a saying I heard as a solder jockey[1] in college.

The inverse is also true, "beware the code of hardware engineers".

That being said, the world's changed a lot since then (30 years now 😱). It's hard to find a modern hardware project that isn't intimately intertwined with huge piles of code. Somehow, days pass and my soldering iron lays cold while I churn out pages of Python and Rust code.

I share my experiences writing one such pile, the control and auto-focus software for IRIS, here: https://www.bunniestudios.com/blog/2024/control-and-autofocus-software-for-chip-level-microscopy/

"Beware the code of hardware engineers". Don't say you haven't been warned!

[1] solder jockey was the moniker bestowed upon undergrads hired to assemble circuit boards for grad students in that particular lab. Minimum-wage labor, but damn, I learned a lot of skills that I use to this day.

Details of IRIS's 2-axis, multi-head light positioner design are now up at https://www.bunniestudios.com/blog/2024/a-2-axis-multihead-light-positioner/

This was by far the most complex mechanical design I've done. Being able to cut, paste, and mashup with the underlying Jubilee3D motion platform's design source was key to everything working so smoothly on the first try. OSHW FTW!