Underclocking The ESP8266 Leads To WiFi Weirdness

January 4, 2019 by Tom Nardi 39 Comments

Sometimes the best hacks come from the most basic of questions. In this case, [CNLohr] was wondering what would happen if he started to reduce the clock speed of the ESP8266’s Baseband PLL (BBPLL) while still trying to communicate with it. You know, as one does. The results ended up being fairly surprising, and while it’s not immediately clear if there’s a practical application for this particular trick, it’s certainly worth some additional research.

The idea here is that the BBPLL is the reference clock for the entire system, including all of the peripherals. So underclocking it doesn’t just slow down code execution as you might expect, but it also slows down the chip’s interactions with the outside world. [CNLohr] demonstrates this concept in the video below, showing how the baud rate used to view the serial output from the ESP8266 needs to be adjusted to match the chip’s frequency or else you’ll only get garbage on the line.

But what happens to the WiFi? As [CNLohr] discovered, while the center frequency itself doesn’t change, the channel width gets narrower as the clock rate is lowered. When viewed on the waterfall display of a software defined radio (SDR), the transmission can be seen “compressing” in a step pattern as the clock rate is reduced. As one might expect, the 802.11 packets become indecipherable to a normal WiFi device running in monitor mode. The signal is still at the correct frequency, but the devices can no longer understand each other.

Now it was time for another of those basic questions. What would happen if you did the same thing to a second ESP8266? Much to his surprise, [CNLohr] discovered that the two devices could still communicate successfully as long as their BBPLL clock speed was the same. From an outsider’s perspective it looked like gibberish, but to the two ESPs which had been slowed by the same amount, everything worked as expected even though the 802.11 standards say it shouldn’t.

So what can you do with this? The most obvious application is a “stealth” WiFi connection between ESP8266s which wouldn’t show up to normal devices, a communications channel invisible to all but the most astute eavesdropper. [CNLohr] has made all the source code to pull this trick off public on GitHub, and it should be interesting to see what kind of applications (if any) hackers find for this standards-breaking behavior.

If your thing is devices being forced into operations they were never intended to by particularly twisted hackers, check out our recent coverage of the USB serial adapter turned SDR by [Ted Yapo].

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Return Of The Logic Probe

January 4, 2019 by Al Williams 10 Comments

We live in a day when it is very inexpensive to buy an oscilloscope, especially one with modest performance that hooks to a laptop. However, there was a time when even a surplus scope was out of reach for many people who liked to build things. A common alternative was the logic probe. At the low end, this could be an inverter and an LED, although it was more common to have a little extra circuitry to actually do a comparison to a reference voltage and present some indication of fast pulses — you might not be able to tell the frequency of a clock, but you could tell it wasn’t stuck. Of course, today with a microcontroller you can make a very sophisticated probe with less circuitry than a classic probe. We’ve seen a few takes on this and the latest is the DigiLogicProbe from [TheRadMan].

The probe is just a ATtiny85 board with a handful of components. A resistor and diode help protect the probe and the circuit under test. There are also a few LEDs and a buzzer. The rest of the project is software.

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Finding The Goldilocks Cell Module

January 4, 2019 by Kerry Scharfglass 29 Comments

If adding a cell modem is dealing with a drama queen of a hardware component, then choosing from among the many types of modules available turns the designer into an electronics Goldilocks. There are endless options for packaging and features all designed to make your life easier (or not!) so you-the-designer needs to have a clear understanding of the forces at work to come to a reasonable decision. How else will Widget D’lux® finally ship? You are still working on Widget D’lux®, aren’t you?

OK, quick recap from last time. Cell modems can be used to add that great feature known as The Internet to your product, which is a necessary part of the Internet of Things, and thus Good. So you’re adding a cell modem! But “adding a cell modem” can mean almost anything. Are you aiming to be Qualcomm and ~~sue Apple~~ build modems from scratch? Probably not. What about sticking a Particle Electron inside to bolt something together quickly? Or talk to Telit and put a bare modem on a board? Unless you’re expecting to need extremely high volume and have a healthy appetite for certification glee, I bet you’ve chosen to get a modem with as many existing certifications as possible, which takes us to where we are today. Go read the previous post if you want a much more elaborate discussion of your modem-packaging options and some of the trade offs involved. Continue reading “Finding The Goldilocks Cell Module” →

The Mystery Of The Clacking Clanking Scraping Sound

January 4, 2019 by Lewin Day 47 Comments

Hackers tend to face household problems a little differently than ordinary folk. Where the average person sees a painful repair bill or a replacement appliance, the hacker sees a difficult troubleshooting job and the opportunity to save some cash. [trochilidae] was woken one day by the dreaded Clacking Clanking Scraping Sound, or CCSS, and knew that something had to be done.

[trochilidae] reports that usually, the CCSS is due to the child of the house destroying his lodgings, but in this case, the source was laundry based. The Miele tumble dryer was acting up, and in need of some attention. What follows is a troubleshooting process [AvE] would be proud of – careful disassembly to investigate the source of the problem. Initial efforts found a loose bulb that was unrelated, before landing on a mysterious spring that wouldn’t fit back into place. In the end, that’s because it had no right to be there at all – an underwire had escaped from a bra, before becoming entangled in the dryer’s bearing. With the culprit identified and removed, it was a simple reassembly job with some attention also paid to the condenser and filters to keep things in ship-shape.

It just goes to show – a bad noise, if properly investigated in a prompt manner, doesn’t have to be the end of the world. A bit of investigation goes a long way, and can save you a lot of money and heartache.

We’ve seen appliances giving hackers trouble before – like this aging washing machine that got its mechanical brain replaced with an Arduino.

Why Converting Classic Cars To Electric Drive Is A Thing

January 4, 2019 by Lewin Day 96 Comments

A vintage British sportscar is a wonderful thing. Inimitable style and luxury, beautiful curves, and a soundtrack that could make even Vinnie Jones shed a tear. However, even under the most diligent maintenance schedule, they are known, above all, for their unreliability. As the value of such cars is tied heavily to their condition as unmodified examples, owners are typically reluctant to make modifications to remedy these issues.

However, things are starting to change. Cities across the world are enacting measures to ban fossil fuel vehicles from their streets, and sales of such vehicles are similarly going to be banned entirely. The automotive industry is preparing for a major pivot towards electric drivetrains, and no carmaker will be left untouched. In this landscape, it’s not just Tesla and Nissan who are selling electric cars anymore. Luxury brands are beginning to deliver electric vehicles, too.

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Karakuri Kaizen: Hacks For The Factory Floor

January 4, 2019 by Roger Cheng 36 Comments

Anyone who has an interest and/or career in manufacturing would have heard of Kaizen, generally a concept to continuously improve your process everywhere. Under that huge umbrella is Karakuri Kaizen, encouraging workers on the factory floor to adopt a hacker mentality and improve their own work stations. It is right up our alley, manufacturer or not, making this overview by Automotive News an entertaining read.

Karakuri could be translated as “mechanism”, but implies something novel in the vein of English words gadgets, gizmos, or dare we say it: hacks. Karakuri has a history dating back to centuries-old wind-up automatons all the way to modern Rube Goldberg contraptions. When applied to modern manufacturing (as part of factory training) it encourages everyone to devise simple improvements. Each might only shave seconds off assembly time, but savings add up in due time.

Modern global manufacturing is very competitive and survival requires producing more efficiently than your competitors. While spotlights of attention may be focused on technology, automation, and construction of “alien dreadnoughts”, that focus risks neglecting gains found at a smaller and simpler scale. Kaizen means always searching for improvements, and the answer is not always more technology.

Several points in these articles asserted purely mechanical karakuri are far less expensive than automated solutions, by comparing price tags which are obviously for industrial automation equipment. We’d be curious to see if our favorite low cost tools — AVR, PIC, ESP32, and friends — would make future inroads in this area. We’ve certainly seen hacks for production at a much smaller scale.

Embedded below the break is a short video from Toyota showing off a few karakuri on their factory floor.

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Pokemon Cries And How They Work

January 4, 2019 by Lewin Day 4 Comments

If you grew up watching the Pokémon TV series, you’d naturally be familiar with the cries of all your favourite Pocket Monsters. Most of the creatures in the anime tend to say their own name, over and over again. Pour one out for the legions of parents who, upon hearing a distant “PIKA PIKA!”, still involuntarily twitch to this day.

However, the games differ heavily in this area. Generation I of Pokémon was released on the Game Boy, which simply didn’t have the sound capabilities to deliver full bitstream audio. Instead, sounds were synthesized for the various Pokémon based on various parameters. It’s quite a deep and involved system, but never fear – help is at hand via [Retro Game Mechanics Explained].

The video breaks down, at a bitwise level, how the parameters are stored for each Pokémon’s cry, and how they are synthesized. It’s broken down into easily understandable chunks, explaining first how the Game Boy’s sound hardware works, with two pulse channels and a noise channel, before later expanding upon why some Pokémon have the same or similar cries.

It’s a tour de force in retro game reverse engineering, and expertly presented with high quality graphical guides as to what’s going on at the software level. There’s even an emulator you can use to explore the various cries from the original game, and generate your own, too.

Now that we’re up to speed with Pokémon, how about fixing bugs in a 37 year old game? Video after the break.

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