A few months ago I started updating TensorFlow Lite Micro for the Raspberry Pi Pico board, which uses the RP2040 microcontroller. I ran into some baffling bugs that stopped me making progress, but eventually I tracked them down to my poor understanding of the memory layout. Since I had to do a deep dive, I wanted to share what I learned here. This diagram shows the physical address layout of the RP2040. I believe the flash location can be board-specific, but on the Pico boards it begins at 0x10000000 and is two megabytes long. Where things get a bit more complex is the RAM. The RP2040 has bui ..read more

Back in 2020 Foone Turing caused a sensation when she showed Doom running on a pregnancy test. For anyone who remembered desktop computers from the 90’s, it was amazing to see a disposable device run something that used to take thousands of dollars worth of hardware. It’s not a fluke either – calculators, ATMs, fridges, and even keychains can run the game. What this shows is how much computing power low-cost, everyday objects now have. If you’d told teenage me that I could buy a 50 cent chip as powerful as my PC, my imagination would have raced with all of the amazing things that people could ..read more

I got my drivers license at 17, on the third attempt, but I never owned a car in the UK since I always biked or took public transport to work. When I was 25 I moved to Los Angeles, so I had to become a car owner for the first time. I wasn’t looking for anything fancy, and so I bought an extremely used 1989 Honda Civic for $2,000 which I drove for years down the 405 on my 90-minute commute from Simi Valley to Santa Monica, before eventually upgrading to the cheapest new car I could find, a Ford Focus, once the Civic became impossible to fix. I drove that across to Colorado and back multiple ti ..read more

As many of you know, I’m an old geezer working on a CS PhD at Stanford and part of that involves me taking some classes. The requirements are involved, but this quarter I ended up taking “Hack Lab: Introduction to Cybersecurity“. I was initially attracted to it because it focuses on the legal as well as the technical side of security, knowledge which could have been useful earlier in my career. I also noticed it was taught by Alex Stamos and Riana Pfefferkorn, two academics with an amazing amount of experience between them, so I expected they’d have a lot to share. I’ve just finished the fina ..read more

Imagine asking a box on a pillar at Home Depot “Where are the nails?” and getting directions, your fridge responding with helpful advice when you say “Why is the ice maker broken?”, or your car answering “How do I change the wiper speed?”. I think of these kinds of voice assistants for everyday objects as “Little Googles”, agents that are great at answering questions, but only in a very specific domain. I want them in my life, but they don’t yet exist. If they’re as useful as I think, why aren’t they already here, and why is now the right time for them to succeed? What are “Little Googles?” I ..read more

As you might know I’m working on my PhD at Stanford, and one of my favorite parts is taking courses. For this second year I need to follow the new foundation and breadth requirements which in practice means taking a course a quarter, with each course chosen from one of four areas. For the fall quarter I took Riana Pfefferkorn and Alex Stamos’ Hacklab: Introduction to Cybersecurity, which I thoroughly enjoyed and learned a lot, especially about the legal side. I’m especially thankful to Danny Zhang, my excellent lab RA who had a lot of patience as I struggled with the difference between a sear ..read more

We all grew up with TV shows, books, and movies that assume everybody can understand each when they speak, even if they’re aliens. There are various in-universe explanations for this convenient feature, and most of them involve a technological solution. Today, the Google Translate app is the closest thing we have to this kind of universal translator, but the experience isn’t good enough to be used everywhere it could be useful. I’ve often found myself bending over a phone with someone, both of us staring at the screen to see the text, and switching back and forth between email or another app ..read more

Photo by Steve Harwood On Friday my long-time colleague Nat asked if we should try and expand our Useful Transformers library into something that could be suitable for a lot more use cases. We worked together on TensorFlow, as did the main author of UT, Manjunath, so he was surprised when I didn’t want to head too far in a generic direction. As I was discussing it with him I realized how much my perspective on ML library design has changed since we started TensorFlow, and since I think by writing I wanted to get my thoughts down as this post. The GGML framework is just over a year old, but it ..read more

At Useful Sensors we’re focused on building intelligent sensors, ones that use machine learning to take raw data and turn it into actionable insights. Sometimes I run across problems in my own life that don’t need advanced algorithms or AI to solve, but are blocked by hardware limitations. A classic one is “Did I leave my garage door open?”. A few months ago I even had to post to our street’s mailing list to ask someone to check it while I was away, since I was anxious I’d left it open. Thankfully several of my great neighbors jumped in and confirmed it was closed, but relying on their patien ..read more

Tomorrow I’ll be giving a remote talk at the LBQNN workshop at ICCV. The topic is the history of quantization in machine learning, and while I don’t feel qualified to give an authoritative account, I did think it might be interesting to cover the developments I was aware of. I don’t know if the talk will be recorded, but here are the slides in case they are useful for reference. Apologies for any mistakes, please do let me know so I can improve the presentation ..read more