A Look Inside A Modern Mixed Signal Oscilloscope

January 18, 2025 by Inderpreet Singh 4 Comments

High-speed bench equipment has become so much more affordable in the last decade that naturally one wonders what has made that possible. A great source of answers is a teardown by users like [kerry wong] who are kind enough to take apart their MSO2304X 300MHz osilloscope for our viewing pleasure.

The posted teardown video shows the guts of the scope without enclosure, heatsinks and shields that reveal a handful of boards that execute the functions nicely. The motherboard uses the Xilinx KINTEX-7 FPGA that is expected to run core processes such as signal processing as well as managing the sample storage on the paired DDR3 memory.

The analog front-end here is a bit of a surprise as it sports TI’s ADC08D1000 ADCs that are capable of 1.3 GSPS but the scope is advertised to be capable of more. The inferred design is that all four ADCs are being operated in an interleaved symphony to achieve 5 GSPS. Testing confirms that each input uses two ADCs at a time and when two or more channels are employed, the reconstruction quality drops.

Continue reading “A Look Inside A Modern Mixed Signal Oscilloscope” →

Stealth AirTag Broadcasts When Moved: An Experiment

January 18, 2025 by Heidi Ulrich 43 Comments

A simple yet intriguing idea is worth sharing, even if it wasn’t a flawless success: it can inspire others. [Richard]’s experiment with a motion-powered AirTag fits this bill. Starting with our call for simple projects, [Richard] came up with a circuit that selectively powers an AirTag based on movement. His concept was to use an inertial measurement unit (IMU) and a microcontroller to switch the AirTag on only when it’s on the move, creating a stealthy and battery-efficient tracker.

The setup is minimal: an ESP32 microcontroller, an MPU-6050 IMU, a transistor, and some breadboard magic. [Richard] demonstrates the concept using a clone AirTag due to concerns about soldering leads onto a genuine one. The breadboard-powered clone chirps to life when movement is detected, but that’s where challenges arise. For one, Apple AirTags are notoriously picky about batteries—a lesson learned when Duracell’s bitter coating blocks functionality. And while the prototype works initially, an unfortunate soldering mishap sadly sends the experiment off the rails.

Despite the setbacks, this project may spark a discussion on the possibilities of DIY digital camouflage for Bluetooth trackers. By powering up only when needed, such a device avoids constant broadcasting, making it harder to detect or block. Whether for tracking stolen vehicles or low-profile uses, it’s a concept rich with potential. We talked about this back in 2022, and there’s an interesting 38C3 talk that sheds quite some light on the broadcasting protocols and standards. Continue reading “Stealth AirTag Broadcasts When Moved: An Experiment” →

I3C Bit-banging Fun For The RP2040

January 18, 2025 by Inderpreet Singh 3 Comments

The RP2040 has quickly become a hot favorite with tinkerers and makers since its release in early 2021. This is largely attributed to the low cost, fast GPIOs, and plethora of bus peripherals. [xyphro] has written the I3C Blaster firmware that helps turn the Raspberry Pi Pico into a USB to I3C converter.

The firmware is essentially a bit-bang wrapper and exposes an interactive shell with a generous command set. But it is a lot more than that. [xyphro] has taken the time to dive into the I3C implementation standard and the code is a fairly complex state-machine that is a story on its own.

[xyphro] provides a Python script in case you feel like automating things or drawing up your GUI. And finally, if you are feeling adventurous, the I3C implementation is available for your project tinkering needs.

We loved the fact there is a branch project that lets you extend a Saleae Logic Analyzer to decode I3C and associated protocols by adding a Pico on the cheap. The last update to the project log shows the addition of a MIPI I3C High Data Rate Mode which operates at 25 Mbps which is right up the RP2040s.

[xyphro] gave us the Home Brew Version Of Smart Tweezers a decade ago and we expect there is more to come. If you are interested in reading more about the I3C bus, have a look at I3C — No Typo — Wants To Be Your Serial Bus.

Investigating USB-to-Ethernet Dongles With “Malware” Claims

January 18, 2025 by Maya Posch 54 Comments

Recently a video surfaced from someone claiming that certain USB-to-Ethernet dongles contained ‘malware’ among other big claims. Basically these dongles were said to be designed by China (and Russia) to spy on users and so on, but how much of this is actually grounded in reality? When [lcamtuf] dove into the topic, what he found was not so much a smoking gun, but rather a curious relic from the era when drivers-on-CD were being phased out.

The item that the video went bananas about was namely an additional SPI Flash chip on the PCB alongside the USB 2.0 – Ethernet IC, with many conspiracy theories being floated as to what it would be used for. After some digging, [lcamtuf] found that the IC used in these dongles (SR9900) is by a company called CoreChips Shenzhen, with a strong suggestions that it is a clone of the (2013-era) Realtek RTL8152B.

Both chips have an external SPI Flash option, which is used with the USB side to present a ‘virtual CD drive’ to the user when the dongle is plugged in. This was borne out with the SR9900 Windows system mass production tool that [lcamtuf] obtained a copy of. Included with the flashing tool is a 168 kB ISO image (containing the SR9900 driver package) which happily fits on the 512 kB Flash chip.

Although it’s always possible for chips and firmware to contain backdoors and malware, in this particular case it would appear to be that it’s merely a cruel reminder that 2013 is now already vanishing into the realm of ‘retro computing’ as us old fogies cling to our driver installation floppies and CDs.

Putting Cheap Motorcycle Tachometers To Work

January 18, 2025 by Tom Nardi 15 Comments

With so much data being thrown at our eyeballs these days, it’s worryingly easy for the actually important stuff to slip by occasionally. So when [Liam Jackson] wanted a way to visualize the number of test failures popping up in the continuous integration system at work, he went with a novel but effective solution — universal motorcycle tachometers.

It turns out these little gauges can be had for under $10 a piece from the usual overseas retailers, and are very easy to drive with a microcontroller. As [Liam] explains, all you need to do other than providing them with 12 volts, is feed them a PWM signal. Even though the gauges are designed for a 12 V system, they apparently don’t have any problem responding to the 5 V logic level from the Arduino’s pins.

As for the frequency he says that 1,000 RPM corresponds to 16.66 Hz, so you can just multiply up from there to show whatever number you wish. That said, [Liam] warns that the gauges draw several hundred milliamps once the needle gets into the two digit range, so keep that in mind. Conveniently, those number happen to be in red anyway…

For his particular application, [Liam] put three of the gauges together to create a very handsome dashboard. If you want to recreate his setup exactly he’s made the STLs available for the gauge cluster housing. Note the small OLED at the center, this offers a way to show a bit more context than the three analog gauges alone can express, especially if you’ve got an application where you might be switching between multiple data sources.

Over the years we’ve seen several projects that repurposed analog gauges of various types, often for showing computer performance, but they generally involved having to drive the galvanometers directly. That these tachometers can simply be fed a simple digital signal should make implementing them into your project much easier.

Learn New Tools, Or Hone Your Skill With The Old?

January 18, 2025 by Elliot Williams 42 Comments

Buried in a talk on AI from an artist who is doing cutting-edge video work was the following nugget that entirely sums up the zeitgeist: “The tools are changing so fast that artists can’t keep up with them, let alone master them, before everyone is on to the next.” And while you might think that this concern is only relevant to those who have to stay on the crest of the hype wave, the deeper question resounds with every hacker.

When was the last time you changed PCB layout software or refreshed your operating system? What other tools do you use in your work or your extra-curricular projects, and how long have you been using them? Are you still designing your analog front-ends with LM358s, or have you looked around to see that technology has moved on since the 1970s? “OMG, you’re still using ST32F103s?”

It’s not a simple question, and there are no good answers. Proficiency with a tool, like for instance the audio editor with which I crank out the podcast every week, only comes through practice. And practice simply takes time and effort. When you put your time in on a tool, it really is an investment in that it helps you get better. But what about that newer, better tool out there?

Some of the reluctance to update is certainly sunk-cost fallacy, after all you put so much sweat and tears into the current tool, but there is also a real cost to overcome to learn the new hotness, and that’s no fallacy. If you’re always trying to learn a new way of doing something, you’re never going to get good at doing something, and that’s the lament of our artist friend. Honing your craft requires focus. You won’t know the odd feature set of that next microcontroller as well as you do the old faithful – without sitting down and reading the datasheet and doing a couple finger-stretching projects first.

Striking the optimal balance here is hard. On a per-project basis, staying with your good old tool or swapping to the new hotness is a binary choice, but across your projects, you can do some of each. Maybe it makes sense to budget some of your hacking time into learning new tools? How about ten percent? What do you think?

JTAG & SWD Debugging On The Pi Pico

January 18, 2025 by Tom Nardi 19 Comments

[Surya Chilukuri] writes in to share JTAGprobe — a fork of the official Raspberry Pi debugprobe firmware that lets you use the low-cost microcontroller development board for JTAG and SWD debugging just by flashing the provided firmware image.

We’ve seen similar projects in the past, but they’ve required some additional code running on the computer to bridge the gap between the Pico and your debugging software of choice. But [Surya] says this project works out of the box with common tools such as OpenOCD and pyOCD.

As we’ve cautioned previously, remember that the Pi Pico is only a 3.3 V device. JTAG and SWD don’t have set voltages, so in the wild you could run into logic levels from 1.2 V all the way to 5.5 V. While being able to use a bare Pico as a debugger is a neat trick, adding in a level shifter would be a wise precaution.

Looking to get even more use out of those Pi Picos you’ve got in the parts bin? How about using it to sniff USB?