Unlocking A Locked-Down Inverter

November 25, 2022 by Jenny List 21 Comments

There was a time when a mains inverter was a heavy, expensive, and not particularly powerful item, but thanks to switch-mode technology we are now spoiled for choice. Most inverters still work with 12 V or 24 V supplies though, so when [Chris Jones] was looking for one to run from 36 V batteries, he found a limited supply. Sadly the Greenworks model he ended up with was affordable, but locked to a particular battery by means of a serial line between battery and inverter. Buy the special battery? No, he did what any hacker would do, and modified the inverter to do without it.

Tracing the serial link led to a mystery chip, probably a microcontroller but without available data. It in turn had a line to an 8051 derivative that seemed to be the brains of the operation. Acting on a hunch he pulled down the line with a resistor, and as if by magic, a working inverter appeared.

As you might expect, here at Hackaday we abhor such tricks by manufacturers, and thus any moves to circumvent them are to be applauded. It would be extremely interesting were anyone to have the Greenworks battery to subject to some reverse engineering of the profile.

Meanwhile if this is a little complex for you, there is a much simpler way to make a rough and ready inverter.

Reverse Engineering “The Seven Words (and More) You Can’t Say On TV”

November 21, 2022 by Dan Maloney 24 Comments

For as visionary as he was, [George Carlin] vastly underestimated the situation with his classic “Seven Words You Can’t Say on TV” bit. At least judging by [Ben Eater]’s reverse engineering of the “TVGuardian Foul Language Filter” device, it seems like the actual number is at least 20 times that.

To begin at the beginning, a couple of weeks ago [Alec] over at everyone’s favorite nerd hangout Technology Connections did a video on the TVGuardian, a device that attempted to clean up the language of live TV and recorded programming. Go watch that video for the details, but for a brief summary, TVGuardian worked by scanning the closed caption text for naughty words and phrases, muted the audio when something suggestive was found in a lookup table, and inserted a closed caption substitute for the offensive content. In his video, [Alec] pined for a way to look at the list of verboten words, and [Ben] accepted the challenge.

The naughty word list ended up living on a 93LC86 serial EEPROM, which [Ben] removed from his TVGuardian for further exploration. Rather than just plug it into a programmer and dumping the contents, he decided to roll his own decoder with an Arduino, because that’s more fun. And can we just point out our ongoing amazement that [Ben] is able to make watching someone else code interesting?

The resulting NSFW word list is titillating, of course, and the video would be plenty satisfying if that’s where it ended. But [Ben] went further and figured out how the list is organized, how the dirty-to-clean substitutions are made, and even how certain words are whitelisted. That last bit resulted in the revelation that Hollywood legend [Dick Van Dyke] gets a special whitelisting, lest his name becomes sanitized to a hilarious [Jerk Van Gay].

Hats off to [Alec] for inspiring [Ben]’s fascinating reverse engineering effort here.

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Scramblepad Teardown Reveals Complicated, Expensive Innards

November 18, 2022 by Donald Papp 28 Comments

What’s a Scramblepad? It’s a type of number pad in which the numbers aren’t in fixed locations, and can only be seen from a narrow viewing angle. Every time the pad is activated, the buttons have different numbers. That way, a constant numerical code isn’t telegraphed by either button wear, or finger positions when punching it in. [Glen Akins] got his hands on one last year and figured out how to interface to it, and shared loads of nice photos and details about just how complicated this device was on the inside.

Just one of the many layers inside the Scramblepad.

Patented in 1982 and used for access control, a Scramblepad aimed to avoid the risk of someone inferring a code by watching a user punch it in, while also preventing information leakage via wear and tear on the keys themselves. They were designed to solve some specific issues, but as [Glen] points out, there are many good reasons they aren’t used today. Not only is their accessibility poor (they only worked at a certain height and viewing angle, and aren’t accessible to sight-impaired folks) but on top of that they are complex, expensive, and not vandal-proof.

[Glen]’s Scramblepad might be obsolete, but with its black build, sharp lines, and red LED 7-segment displays it has an undeniable style. It also includes an RFID reader, allowing it to act as a kind of two-factor access control.

On the inside, the reader is a hefty piece of hardware with multiple layers of PCBs and antennas. Despite all the electronics crammed into the Scramblepad, all by itself it doesn’t do much. A central controller is what actually controls door access, and the pad communicates to this board via an unencrypted, proprietary protocol. [Glen] went through the work of decoding this, and designed a simplified board that he plans to use for his own door access controller.

In the meantime, it’s a great peek inside a neat piece of hardware. You can see [Glen]’s Scramblepad in action in the short video embedded below.

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Reverse Engineering Reveals EV Charger Has A Sense Of Security

November 16, 2022 by Dan Maloney 11 Comments

As more and more electric vehicles penetrate the market, there’s going to have to be a proportional rise in the number of charging stations that are built into parking garages, apartment complexes, and even private homes. And the more that happens, the more chargers we’re going to start seeing where security is at best an afterthought in their design.

But as this EV charger teardown and reverse engineering shows, it doesn’t necessarily have to be that way. The charger is a Zaptec Pro station that can do up to 22 kW, and the analysis was done by [Harrison Sand] and [Andreas Claesson]. These are just the kinds of chargers that will likely be widely installed over the next decade, and there’s surprisingly little to them. [Harrison] and [Andreas] found a pair of PCBs, one for the power electronics and one for the control circuits. The latter supports a number of connectivity options, like 4G, WiFi, and Bluetooth, plus some RFID and powerline communications. There are two microcontrollers, a PIC and an ARM Cortex-A7.

Despite the ARM chip, the board seemed to lack an obvious JTAG port, and while some unpopulated pads did end up having a UART line, there was no shell access possible. An on-board micro SD card slot seemed an obvious target for attack, and some of the Linux images they tried yielded at least a partial boot-up, but without knowing the specific hardware configuration on the board, that’s just shooting in the dark. That’s when the NAND flash chip was popped off the board to dump the firmware, which allowed them to extract the devicetree and build a custom bootloader to finally own root.

The article has a lot of fascinating details on the exploit and what they discovered after getting in, like the fact that even if you had the factory-set Bluetooth PIN, you wouldn’t be able to get free charging. So overall, a pretty good security setup, even if they were able to get in by dumping the firmware. This all reminds us a little of the smart meter reverse engineering our friend [Hash] has been doing, in terms of both methodology and results.

Thanks to [Thinkerer] for the tip.

An iPhone sits in a users hand open to the YouTube app. What is unusual is that the iPhone is bent in an L shape and is still functioning properly.

First Folding IPhone Doesn’t Come From Apple

November 11, 2022 by Navarre Bartz 26 Comments

Folding phones are all the rage these days, with many of the major smartphone manufacturer’s having something in this form factor. Apple has been conspicuously absent in this market segment, so [KJMX] decided to take matters into their own hands with the “iPhone V.” (YouTube – Chinese w/subtitles via MacRumors).

Instead of trying to interface an existing folding phone’s screen with the iPhone, these makers delaminated an actual iPhone X screen to use in the mod. It took 37 attempts before they had a screen with layers that properly separated to be both flexible and functional. Several different folding phones were disassembled, and [KJMX] found a Motorola Razr folding mechanism would work best with the iPhone X screen. Unfortunately, since the iPhone screen isn’t designed to fold, it still will fail after a relatively small number of folds.

Other sacrifices were made, like the removal of the Taptic Engine and a smaller battery to fit everything into the desired form factor. The “iPhone V” boasts the worst battery life of any iPhone to date. After nearly a year of work though, [KJMX] can truly claim to have made what Apple hasn’t.

Curious about other hacks to let an iPhone do more than Apple intended? Check out how to add USB-C to an iPhone, try to charge it faster, or give one a big memory upgrade.

IR Remote tester in use, showing a remote control lighting up an LED and screenshots of the Arduino serial terminal

IR Remote Tester Helps You Crack The Code

November 8, 2022 by Dave Walker 15 Comments

Even though some devices now use WiFi and Bluetooth, so much of our home entertainment equipment still relies on its own proprietary infrared remote control. By and large (when you can find them) they work fine, but what happens when they stop working? First port of call is to change the batteries, of course, but once you’ve tried that what do you do next? [Hulk] has your back with this simple but effective IR Remote Tester / Decoder.

IR remote tester schematic showing arduino, receiver, LED and resistor — How to connect the TSOP4838 to an Arduino to read the transmitted codes

By using a cheap integrated IR receiver/decoder device (the venerable TSOP4838), most of the hard work is done for you! For a quick visual check that your remote is sending codes, it can easily drive a visible LED with just a resistor for a current-limit, and a capacitor to make the flickering easier to see.

For an encore, [Hulk] shows how to connect this up to an Arduino and how to use the “IRremote” library to see the actual data being transmitted when the buttons are pressed.

It’s not much of a leap to imagine what else you might be able to do with this information once you’ve received it – controlling your own projects, cloning the IR remote codes, automating remote control sequences etc..

It’s a great way to make the invisible visible and add some helpful debug information into the mix.

We recently covered a more complex IR cloner, and if you need to put together a truly universal remote control, then this project may be just what you need.

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Your Car Has Driving Profiles – Here’s How To Change Them

November 2, 2022 by Arya Voronova 24 Comments

Just like mobile phones of yesteryear, modern cars have profiles. They aren’t responsible for the sounds your car produces, however, as much as they change how your car behaves – for instance, they can make your engine more aggressive or tweak your steering resistance. On MQB platform cars, the “Gateway” module is responsible for these, and it’s traditionally been a black box with a few user-exposed profiles – not as much anymore, thanks to the work of [Jille]. They own a Volkswagen hybrid car, and had fun changing driving modes on it – so naturally, they decided to reverse-engineer the configuration files responsible.

Now, after two years of experimentation, tweaking values and observing changes, there’s quite some sense made of the configuration binaries. You can currently edit these binaries, also referred to as datasets, in a hex editor – there’s profiles for the 010 hex editor that make sense of the data you load, and explanation of the checksums involved. With this, you are no longer limited by profiles the manufacturer composed – if a slightly different driving combination of parameters makes more sense to you, you can recombine them and have your own profile, unlock modes that the manufacturer decided to lock out for non-premium cars, and even fix some glaring oversights in factory modes.

This is pretty empowering, and far from ECU modifications that introduce way more fundamental changes to how your car operates – the parameters being changed are within the range of what the manufacturer has implemented. The smarter our cars become, the more there is for us hackers to tweak, and even in a head unit, you can find things to meaningfully improve given some reverse-engineering smarts.