Embedded Python: MicroPython Toolkits

August 5, 2024 by Arya Voronova 22 Comments

Last time, I talked about how MicroPython is powerful and deserving of a place in your toolkit, and it made for a lively discussion. I’m glad to see that overall, MicroPython has indeed been getting the recognition it deserves – I’ve built a large number of wonderful projects with it, and so have people I’ve shown it to!

Sometimes I see newcomers dissatisfied with MicroPython, because the helper tools they initially pick don’t suit it well. For instance, they try and start out with a regular serial terminal application that doesn’t fit the MicroPython constraints, or a general IDE that requires a fair bit of clicking around every time you need to run your code. In particular, I’d make sure that you know your options no matter whether you prefer GUI or commandline – both have seriously nice tools for MicroPython use!

The main problem to be solved with MicroPython is that you have a single serial port that everything happens through – both file upload and also debugging. For ESP8266/32-based boards, it’s a physical serial port, and for chips like RP2040 and ESP32-S* where a hardware USB peripheral is available, it’s a virtual one – which makes things harder because the virtual port might get re-enumerated every now and then, possibly surprising your terminal application. If you want to upload a program of yours, you need to free up the serial port, and to see the program’s output, you will need to reopen that port immediately after – not a convenient thing to do if you’re using something like PuTTy.

So, using MicroPython-friendly software is a must for a comfortable hacking experience. What are your options? Continue reading “Embedded Python: MicroPython Toolkits” →

Getting Linux Process List Without Forking Using Just A Bash Script

July 29, 2024 by Maya Posch 16 Comments

The ps command is extremely useful when you want to get some quick information on active system processes (hence the name), especially followed by piping it into grep and kin for some filtering. One gotcha is of course that ps doesn’t run in the current shell process, but is forked off into its own process, so what if everything goes wrong and you absolutely need to run ps aux on a system that is completely and utterly out of fresh process IDs to hand out? In that scenario, you fortunately can write a shell script that does the same, but all within the same shell, as [Isabella Bosia] did, with a Bash shell script.

The how and why is mostly covered in the shell script itself, using detailed comments. Initially the hope was to just read out and parse the contents of /proc/<pid>/status, but that doesn’t have details like CPU%. The result is a bit more parsing to get the desired result, as well as a significant amount of cussing in the comments. Even if it’s not entirely practical, as the odds of ending up on a system with zero free PIDs are probably between zero and NaN, but as an ‘entertaining’ job interview question and example of all the fun things one can do with shell scripting it’s definitely highly recommended.

Hacker Tactic: Multi-Design Panels

July 29, 2024 by Arya Voronova 12 Comments

Last time, we talked about single-PCB-design panels, all the cool aspects of it, including some cost savings and handling convenience. Naturally, you might wonder, and many did – can you put multiple different PCBs on a single panel? The answer is “yes, without a doubt!” The tool we used last time, KiKit, will not be as helpful here, so we’ll be looking elsewhere.

Making multi-PCB panels can help you save money, naturally, but it can also make your assembly a whole lot easier, and it can bring you hacking to a whole new level. It sure helped with mine! You might have already learned that some fabs scoff at multi-design panels and add surcharges. Well, you’ll be delighted to learn that there are more hacker-friendly fabs out there, too.

Developing PCBs In Bulk

So far, I’ve worked on about 300 different PCB designs, with half of them available in my monorepo. I’ve assembled and tested just about half of these. You might guess that this would cost a lot of money, and that assembly would take a fair bit of time, but I have some tricks up my sleeve. For a start, you can easily order PCBs 10-12 times more cheaply if you do multi-panel.

Continue reading “Hacker Tactic: Multi-Design Panels” →

Watch This RC Jet Thrust System Dance

July 19, 2024 by Donald Papp 7 Comments

An EDF (electric duct fan) is a motor that basically functions as a jet engine for RC aircraft. They’re built for speed, but to improve maneuverability (and because it’s super cool) [johnbecker31] designed a 3D-printable method of adjusting the EDF’s thrust on demand.

Before 3D printers were common, making something like this would have been much more work.

The folks at Flite Test released a video in which they built [john]’s design into a squat tester jet that adjusts thrust in sync with the aircraft’s control surfaces, as you can see in the header image above. Speaking of control surfaces, you may notice that test aircraft lacks a rudder. That function is taken over by changing the EDF’s thrust, although it still has ailerons that move in sync with the thrust system.

EDF-powered aircraft weren’t really feasible in the RC scene until modern brushless electric motors combined with the power density of lithium-ion cells changed all that. And with electronics driving so much, and technology like 3D printers making one-off hardware accessible to all, the RC scene continues to be fertile ground for all sorts of fascinating experimentation. Whether it’s slapping an afterburner on an EDF or putting an actual micro jet engine on an RC car.

Continue reading “Watch This RC Jet Thrust System Dance” →

A devboard with the CH32V003, with a few resistors and bodges, with a USB-C cable plugged into it, and a programmer plus an extra probe attached.

USB PD On CH32V003 Teaches You Everything

July 2, 2024 by Arya Voronova 5 Comments

How do you talk USB Power Delivery (PD)? Grab a PHY? Use a MCU with one built-in? Well, if you’re hardcore enough, you can do it with just a few resistors and GPIOs. [eeucalyptus] shows you their implementation of USB-PD on a CH32V003, which has no PD peripheral. This includes building a PD trigger, completely open source, and walking you through the entire low-level PD basics, too!

It helps that CH32V003 is a 32-bit MCU with a good few resources and peripherals, for instance, an internal comparator. Other than that, you don’t need much in terms of hardware resources, but you do need a steady hand — parts of the firmware had to be written in assembly to keep up with PD timing. Want to tinker with the fruit of this research, perhaps, further build upon the code? There’s an example board on GitHub, too!

Want to try your own luck with this method? There’s a schematic, and logic analyzer captures, and a board to refer to. Again, more than enough information on every single low-level detail! Otherwise, grab an MCU pre-programmed to talk PD, maybe a trigger board chip, or maybe even a PD PHY and implement PD communications with it directly – it’s pretty easy!

We thank [Julianna] for sharing this with us!

The splitter with a 3D-printed case and three yellow cables coming out of it, powering two phones and one powerbank at the same time

Split A USB-C PD Port Into Three Port-ions

July 1, 2024 by Arya Voronova 9 Comments

There’s no shortage of USB-C chargers in all sorts of configurations, but sometimes, you simply need a few more charging ports on the go, and you got a single one. Well then, check out [bluepylons]’s USB-C splitter, which takes a single USB-C 5V/3A port and splits it into three 5V/1A plugs, wonderful for charging a good few devices on the go!

This adapter does things right – it actually checks that 3A is provided, with just a comparator, and uses that to switch power to the three outputs, correctly signalling to the consumer devices that they may consume about 1A from the plugs. This hack’s documentation is super considerate – you get detailed instructions on how to reproduce it, every nuance you might want to keep in mind, and even different case options depending on whether you want to pot the case or instead use a thermal pad for a specific component which might have to dissipate some heat during operation!

This hack has been documented with notable care for whoever might want to walk the journey of building one for themselves, so if you ever need a splitter, this one is a wonderful weekend project you are sure to complete. Wonder what kind of project would be a polar opposite, but in all the best ways? Why, this 2kW USB-PD PSU, most certainly.

A graphic representing the features of a Sleep Number smart bed, showing individually controlled heated zones

Root Your Sleep Number Smart Bed, Discover It Phoning Home

June 30, 2024 by Arya Voronova 63 Comments

Did you know you can get a “smart bed” that tracks your sleep, breathing, heart rate, and even regulates the temperature of the mattress? No? Well, you can get root access to one, too, as [Dillan] shows, and if you’re lucky, find a phone-home backdoor-like connection. The backstory to this hack is pretty interesting, too!

You see, a Sleep Number bed requires a network connection for its smart features, with no local option offered. Not to worry — [Dillan] wrote a Homebridge plugin that’d talk the cloud API, so you could at least meaningfully work with the bed data. However, the plugin got popular, Sleep Number didn’t expect the API to be that popular. When they discovered the plugin, they asked that it be shut down. Tech-inclined customers are not to be discouraged, of course.

Continue reading “Root Your Sleep Number Smart Bed, Discover It Phoning Home” →