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chrisb commented on Ask HN: What is the most complex software you've built single handedly?    · Posted by u/chistev
chrisb · 9 days ago
Many years ago, a moderately complete interpreted .NET runtime - https://github.com/chrisdunelm/DotNetAnywhere

This was long before .NET Core, and was designed to allow C# to be used on highly limited platforms

chrisb commented on Ask HN: What Are You Working On? (June 2025)    · Posted by u/david927
AussieCoder · 6 months ago
I invested in Small Robots Co (https://smallrobotco.com/) who were doing something similar. They had a good product, good brand, raised some funding, and were starting to get traction, with robots in trials on a number of farms, but at the end of the day they ran out of funding before they reached default-alive.

It's a tough space - convincing farmers to give it a go and running trials takes time and the UK isn't a very startup-friendly environment - investors are too often looking for a quick return.

This is such an important area - it's only going to become more critical to be able to grow more food whilst using less fertiliser and weed killer - so I wish you the very best of luck!

chrisb · 6 months ago
Nice to meet an SRC investor :)

Yes, it was all very sad the way SRC ended.

Coincidentally, we're based fairly close to where they operated. We are in touch with some of the people that used to be involved with SRC, and have been able to learn from some of their experiences. There is agreement that the UK can be difficult for this kind of startup, but also about the importance of the product area.

chrisb commented on Ask HN: What Are You Working On? (June 2025)    · Posted by u/david927
pistachiosPower · 6 months ago
Very Cool!! I'm pretty new to the robotics world, why are you avoiding ROS?
chrisb · 6 months ago
My knowledge of ROS is a couple of years out of date, but primarily that reproducible testing and simulation, with precise time/clock management, which is essential for a reliable product, was very difficult in ROS.

I also felt the ROS build system more convoluted than necessary; and seemed rather brittle - it was too easy to break it with OS or other updates.

We found that many off-the-shelf ROS nodes didn't do quite what we wanted, and ended up spending much more time than expected rewriting code that we expected we wouldn't need to. It is quicker, and we end up with less & more maintainable code, by writing it ourselves.

I expect this could have been resolved, but when testing ROS we also ended up using more compute resources on-robot than we expected.

Using our own system allows us to build exactly what we require, which has become more important as our system gets larger and more complex; and means integrations into other systems (including testing) are easier.

chrisb commented on Ask HN: What Are You Working On? (June 2025)    · Posted by u/david927
worik · 6 months ago
Very interesting

I have seen a few of these, but only one (about a decade ago) that used legs not wheels

Wouldn't it be better if the robot walked rather than rolled?

You may be able to illuminate this for me...

chrisb · 6 months ago
Before we started building we considered many different designs, including legs. However, it introduces significant extra mechanical and control complexity, with more complex failure modes - e.g. one leg gets stuck in the mud; it also would be more expensive to build.

So we decided to stick with wheels, at least for this product iteration!

chrisb commented on Ask HN: What Are You Working On? (June 2025)    · Posted by u/david927
chrisb · 6 months ago
https://spring-agriculture.com/

Autonomous robotics for sustainable agriculture. Based in the south of the UK. Prototypes of an autonomous mechanical farm-scale weeding robot currently beginning real-world testing. Still a huge amount of work to do though.

Hardware and software developed fairly much from scratch, not using ROS (for not entirely crazy reasons...); everything written in Rust which I find well suited to this application area.

The robot is built using off-the-shelf components and 3d-printed custom parts, so build cost is surprisingly low, and iterations are fast (well, for hardware dev).

On robot compute is a couple of Raspberry Pi 5s.

Currently using the RPi AI Kit for image recognition, ie Hailo 8[L] accelerators.

Not currently using any advanced robotics VLA-type AI models, but soon looking to experiment with some of it, initially in simulation.

Feel free to get in touch if you'd like to talk :) Contact details in my HN profile, and on our website.

chrisb commented on Fire at South Korea lithium battery plant kills at least 16 people   nbcnews.com/news/world/fi... · Posted by u/rntn
chrisb · 2 years ago
These are apparently not large EV-type rechargeable lithium batteries, as I immediately assumed.

From the article: "Aricell makes lithium primary batteries for sensors and radio communication devices". A "primary battery" is non-rechargeable; and given the use-cases mentioned I expect each individual battery is fairly small.

Of course, when there are 10s of 1000s of them together that's still a lot of energy to burn.

chrisb commented on Bringing Back Horizontal Rules in HTML Select Elements   webkit.org/blog/14933/bri... · Posted by u/ingve
OJFord · 2 years ago
TFA mentions `optgroup` too, wouldn't it make more sense to use that and style it similarly? Especially if `hr`-in-`select` is only going to work in Safari anyway(?).
chrisb · 2 years ago
The article isn't completely clear; but hr-in-select is standardized [0] - and it definitely works in the Firefox v122.0 I'm browsing with.

[0] https://html.spec.whatwg.org/multipage/form-elements.html#th... (see the "Content model" line)

chrisb commented on A Fire Upon The Deep By Vernor Vinge (1992)   archive.org/details/fireu... · Posted by u/optimalsolver
chrisb · 2 years ago
The subsequent prequel "A deepness in the sky" is also well worth a read.
chrisb commented on Stellantis CEO: There may not be enough raw materials to electrify globe   detroitnews.com/story/bus... · Posted by u/clouddrover
hitpointdrew · 3 years ago
Not only are there not enough resources, our electric grid is nowhere near where it needs to be to remotely support a large shift to EVs. Any ideas that in 5-10 years we will only sell EVs is a grand delusion.
chrisb · 3 years ago
This claim of grid overload is false.

See [0] for the UK grid operator's view on this, also includes a few numbers relevant to the US grid.

[0] https://www.nationalgrid.com/stories/journey-to-net-zero/ele...

u/chrisb

KarmaCake day529April 30, 2009
About
Contact me at chris _at_ dunelm.org.uk

Located just south of London, UK

Github: https://github.com/chrisdunelm

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