Walter Is A Tiny Cellular Modem For Your Projects

August 16, 2025 by Tyler August 21 Comments

It wasn’t that long ago that projects with cellular connectivity were everywhere, but with 2G no longer universally available, glory days of cheap 2G modules seem to be on their way out. So when [Data Slayer] titled his video “You’ve Never Seen Cellular Like This” about a new GSM radio module, we couldn’t help but think that we have — and that we’re glad to see it back.

The module is the Walter, by DPTechnics out of Belgium. It’s fully open-source and contains a ESP32-S3 for WiFi and BLE plus a Sequans Monarch chip for GSM and GNSS connectivity. It’s not the blazing-fast 5G you’re paying your phone carrier for: this is an IoT modem, with LTE-M and NB-IoT. We’re talking speeds in the kbps, not Mbps– but we’re also talking very, very low power usage. Since it’s LTE-M rather than full LTE, you’re probably not going to be bringing back the golden days of Arduino Cellphones, (since LTE-M doesn’t support VoLTE) but if LoRa isn’t your jam, and you hang out around cell towers, this level of connectivity might interest you.

Walter is actually a drop-in replacement for PyCom’s old GPy module, so if you had a project in mind for that and are frustrated by it being EoL — well, here you are. [Data Slayer] seemed impressed enough with its capabilities as a GPS tracker. We’re impressed with the 9.8 µA consumed in deep sleep mode, and the fact that it has already been certified with the CE, FCC, IC, RCM and UKCA. Those certs mean you could go from prototype to product without getting tangled in red tape, assuming Walter is the only radio onboard.

Our thanks to [Keith Olson] for phoning in the tip. If you have a tip and want to connect, operators are standing by. Continue reading “Walter Is A Tiny Cellular Modem For Your Projects” →

BhangmeterV2 Answers The Question “Has A Nuke Gone Off?”

June 18, 2025 by Tyler August 48 Comments

You might think that a nuclear explosion is not something you need a detector for, but clearly not everyone agrees. [Bigcrimping] has not only built one, the BhangmeterV2, but he has its output publicly posted at hasanukegoneoff.com, in case you can’t go through your day without checking if someone has nuked Wiltshire.

The Bhangmeter is based on an off-the-shelf “nuclear event detector”, the HSN-1000L by Power Device Corporation.

The HSN 1000 Nuclear Event Detector at the heart of the build. We didn’t know this thing existed, never mind that it was still available.

Interfacing to the HSN-1000L is very easy: you give it power, and it gives you a pin that stays HIGH unless it detects the characteristic gamma ray pulse of a nuclear event. The gamma ray pulse occurs at the beginning of a “nuclear event” precedes the EMP by some microseconds, and the blast wave by perhaps many seconds, so the HSN-1000 series seems be aimed at triggering an automatic shutdown that might help preserve electronics in the event of a nuclear exchange.

[Bigcrimping] has wired the HSN-1000L to a Raspberry Pi Pico 2 W to create the BhangmeterV2. In the event of a nuclear explosion, it will log the time the nuclear event detector’s pin goes low, and the JSON log is pushed to the cloud, hopefully to a remote server that won’t be vaporized or bricked-by-EMP along with the BhangmeterV2. Since it is only detecting the gamma ray pulse, the BhangmeterV2 is only sensitive to nuclear events within line-of-sight, which is really not where you want to be relative to a nuclear event. Perhaps V3 will include other detection methods– maybe even a 3D-printed neutrino detector?

If you survive the blast this project is designed to detect, you might need a radiation detector to deal with the fallout. For identifying exactly what radionuclide contamination is present, you might want a gamma-ray spectrometer.

It’s a sad comment on the modern world that this hack feels both cold-war vintage and relevant again today. Thanks to [Tom] for the tip; if you have any projects you want to share, we’d love to hear from you whether they’d help us survive nuclear war or not.

Open Source Framework Aims To Keep Tidbyt Afloat

March 29, 2025 by Tom Nardi 10 Comments

We recently got a note in the tips line from [Tavis Gustafson], who is one of the developers of Tronbyt — a replacement firmware and self-hosted backend that breaks the Tidbyt smart display free from its cloud dependency. When they started the project, [Tavis] says the intent was simply to let privacy-minded users keep their data within the local network, which was itself a goal worthy enough to be featured on these pages.

But now that Tidbyt has been acquired by Modal and has announced they’ll no longer be producing new units, things have shifted slightly. While the press release says that the Tidbyt backend is going to stay up and running for existing customers, the writing is clearly on the wall. It’s now possible that the Tronbyt project will be able to keep these devices from ending up in landfills when the cloud service is inevitably switched off, especially if they can get the word out to existing users before then.

What’s that? You say you haven’t heard of Tidbyt? Well, truth be told, neither had we. So we did some digging, and this is where things get really interesting.

Continue reading “Open Source Framework Aims To Keep Tidbyt Afloat” →

A Guide To Making The Right Microcontroller Choice

February 14, 2025 by Dan Maloney 50 Comments

Starting a new microcontroller project can be pretty daunting. While you have at least a rough idea of where you want to end up, there are so many ways to get there that you can get locked into “analysis paralysis” and never get the project off the ground. Or arguably worse, you just throw whatever dev board you have in the junk bin and deal with the consequences.

While it’s hard to go wrong with relying on a familiar MCU and toolchain, [lcamtuf] argues in this recent guide to choosing microcontrollers that it’s actually not too much of a chore to make the right choice. Breaking the microcontroller universe down into three broad categories makes the job a little easier: simple process control, computationally intensive tasks, and IoT products. Figuring out where your project falls on that spectrum narrows your choices considerably.

For example, if you just need to read some sensors and run a few servos or solenoids, using something like a Raspberry Pi is probably overkill. On the other hand, a Pi or other SBC might be fine for something that you need wireless connectivity. We also appreciate that [lcamtuf] acknowledges that intangible considerations sometimes factor in, such as favoring a new-to-you MCU because you’ll get experience with technology you haven’t used before. It might not override technical considerations by itself, but you can’t ignore the need to stretch your wings once in a while.

There’s nothing earth-shattering here, but we enjoy think pieces like this. It’s a bit like [lcamtuf]’s recent piece on rethinking your jellybean op-amps.

This Week In Security: Backdoored Backdoors, Leaking Cameras, And The Safety Label

January 10, 2025 by Jonathan Bennett 3 Comments

The mad lads at watchTowr are back with their unique blend of zany humor and impressive security research. And this time, it’s the curious case of backdoors within popular backdoors, and the list of unclaimed domains that malicious software would just love to contact.

OK, that needs some explanation. We’re mainly talking about web shells here. Those are the bits of code that get uploaded to a web server, that provide remote access to the computer. The typical example is a web application that allows unrestricted uploads. If an attacker can upload a PHP file to a folder where .php files are used to serve web pages, accessing that endpoint runs the arbitrary PHP code. Upload a web shell, and accessing that endpoint gives a command line interface into the machine.

The quirk here is that most attackers don’t write their own tools. And often times those tools have special, undocumented features, like loading a zero-size image from a .ru domain. The webshell developer couldn’t be bothered to actually do the legwork of breaking into servers, so instead added this little dial-home feature, to report on where to find all those newly backdoored machines. Yes, many of the popular backdoors are themselves backdoored.

This brings us to what watchTowr researchers discovered — many of those backdoor domains were either never registered, or the registration has been allowed to expire. So they did what any team of researchers would do: Buy up all the available backdoor domains, set up a logging server, and just see what happens. And what happened was thousands of compromised machines checking in at these old domains. Among the 4000+ unique systems, there were a total of 4 .gov. domains from governments in Bangladesh, Nigeria, and China. It’s an interesting romp through old backdoors, and a good look at the state of still-compromised machines.

Continue reading “This Week In Security: Backdoored Backdoors, Leaking Cameras, And The Safety Label” →

Compact Driver Powers Steppers With USB-C PD

August 24, 2024 by Dan Maloney 12 Comments

NEMA-17 steppers are (almost) a dime a dozen. They’re everywhere, they’re well-known to hackers and makers, and yet they’re still a bit hard to integrate into projects. That’s because the motor alone isn’t much use, and by the time you find or build a driver and integrate it with a microcontroller, you’ve probably expended more effort than you will on the rest of the project. This USB-C PD stepper driver aims to change that.

What caught our eye about [Josh Rogan]’s PD Stepper is his effort to make this a product rather than just a project. The driver is based on a TMC2209 for silent operation and a lot of torque thanks to the power delivery capabilities of USB-C PD. The PCB is very nicely designed and has an AS5600 rotary magnetic encoder for closed-loop operation. There’s also an ESP32-S3 on-board, so WiFi and Bluetooth operation are possible — perfect for integration into Home Assistant via ESPHome.

[Josh]’s mechanical design is top-notch, too, with a machined aluminum spacer that fits on the back of a NEMA-17 motor perfectly and acts as a heat spreader. A machined polycarbonate cover protects the PCB and makes a very neat presentation. [Josh] has kits available, or you can roll your own with the provided build files.

Continue reading “Compact Driver Powers Steppers With USB-C PD” →

Hackaday Links: August 11, 2024

August 11, 2024 by Dan Maloney 8 Comments

“Please say it wasn’t a regex, please say it wasn’t a regex; aww, crap, it was a regex!” That seems to be the conclusion now that Crowdstrike has released a full root-cause analysis of its now-infamous Windows outage that took down 8 million machines with knock-on effects that reverberated through everything from healthcare to airlines. We’ve got to be honest and say that the twelve-page RCA was a little hard to get through, stuffed as it was with enough obfuscatory jargon to turn off even jargon lovers such as us. The gist, though, is that there was a “lack of a specific test for non-wildcard matching criteria,” which pretty much means someone screwed up a regular expression. Outside observers in the developer community have latched onto something more dire, though, as it appears the change that brought down so many machines was never tested on a single machine. That’s a little — OK, a lot — hard to believe, but it seems to be what Crowdstrike is saying. So go ahead and blame the regex, but it sure seems like there were deeper, darker forces at work here.

Continue reading “Hackaday Links: August 11, 2024” →