Battery Analyzer Puts Alkaline Cells To The Test

April 20, 2021 by Tom Nardi 61 Comments

We know, we know. Generally speaking, you should try and switch your household devices over to rechargeable cells rather than using disposable alkaline batteries. But while they might seem increasingly quaint in the lithium-ion era, features such as a long shelf life make it worth keeping a pack of disposables around. So which ones should you buy? That’s what [Moragor] wanted to find out with his personal battery analyzer.

Designed as a shield for the Arduino Mega 2560, the analyzer combines a small programmable electronic load with a INA219 current sensor, OLED display, and SD card reader. The user selects the cutoff voltage and discharge rate before the test begins, and once it’s running, data is collected every second and saved to the SD card for later analysis. Once the battery voltage reaches the predetermined value, the test is over and you’re ready to put a new cell through its paces.

After testing 27 different brands of batteries, [Moragor] tabulated all the data and produced some helpful charts to illustrate the results. With few exceptions, the performance level for most of the batteries was remarkably similar. If anything, the test seemed to show that higher tier batteries from companies like Duracell and Energizer actually performed slightly worse than the mid-range offerings. Perhaps the biggest surprise is that, when the per-cell cost was factored in, the local cheapo batteries provided a better value than anything else in the test.

While the selection of battery brands may be different from where you live, the data [Moragor] collected is still a fascinating even if you don’t recognize some of the names on the chart. Of particular note is the confirmation that lithium batteries handily outperformed any of the Alkaline cells tested when it came to high-drain applications. We’d still rather they came in rechargeable form, but at least it’s a step in the right direction.

Camera Hack Peels Back Layers Of Embedded Linux

April 20, 2021 by Tom Nardi 18 Comments

Embedded Linux devices are everywhere these days, and sooner or later, you’re going to want to poke around in one of them. But how? That’s where posts like this one from [Felipe Astroza] come in. While his work is focused on the Foscam C1 security camera, the techniques and tools he outlines here will work on all sorts of gadgets that have a tiny penguin at their core.

Rather than trying to go in through the front door, [Felipe] starts his assault with the nuclear option: removing the SPI MX25L12835F flash chip from the camera’s PCB and dumping its contents with a Raspberry Pi. From there he walks through the use of different tools to determine the partition scheme of the chip and eventually extract passwords and other interesting bits of information from the various file systems within.

That alone would be worth the read, but things really get interesting once [Felipe] discovers the FirmwareUpgrade program. Since the Foscam’s software updates are encrypted, he reasons that reverse engineering this binary would uncover the key and allow for the creation of custom firmware images that can be flashed through the stock interface.

Further investigation with Ghidra and friends identifies an interesting shared library linked to the executable in question, which is then disassembled in an effort to figure out how the key is being obfuscated. We won’t ruin the surprise, but [Felipe] eventually gets what he’s after.

This isn’t the first time [Felipe] has played around with the firmware on these Internet connected cameras, and we dare say it won’t be his last. For those who are really into tinkering with these sort of devices, it’s not unheard of to install a socket for the flash chip to make software modifications faster and easier.

LED Hack Teaches DJI Mini 2 Drone New Tricks

April 20, 2021 by Tom Nardi 18 Comments

Despite its diminutive proportions, the thrust to weight ratio of the DJI Mini 2 is high enough that it can carry a considerable amount of baggage. So it’s no surprise that there’s a cottage industry of remotely controlled payload releases that can be bolted onto the bottom of this popular quadcopter. But [tterev3] wanted something that would integrate better with DJI’s software instead of relying on a separate transmitter.

As explained in the video below, his solution was to tap into the signals that control the RGB LED on the front of the drone. Since the user can change the color of the LED at any time with the official DJI smartphone application, decoding this signal to determine which color had been selected is like adding several new channels to the transmitter. In this case [tterev3] just needed to decode a single color to use as a “drop” signal, but it’s not hard to imagine how this concept could be expanded to trigger several different actions with a few more lines of code.

[tterev3] wrote some software to decode the 48 bits of data being sent to the LED with a PIC18F26K40 microcontroller, which in turn uses an L9110H H-Bridge to control a tiny gear motor. To get feedback, he’s using a small magnet glued to the release arm and a Hall-effect sensor.

Concerned about how much power he could realistically pull from a connection that was intended for an LED, he gave the release its own battery that is slowly charged while the drone is running. You could argue that since the motor only needs to fire up once to drop the payload, [tterev3] probably could have gotten away with not recharging it at all during the flight. But as with the ability to decode additional color signals, the techniques being demonstrated here hold a lot of promise for future development.

Folks have been strapping additional hardware to commercial quadcopters for years, but modifications like this one that actually let the craft release its payload and fly away hold particular promise for environmental monitoring and building mesh communication networks.

Continue reading “LED Hack Teaches DJI Mini 2 Drone New Tricks” →

Replacing An ESP8266 Clone With The Real Thing

April 17, 2021 by Tom Nardi 19 Comments

The first time [konbaasiang] ordered some ceiling LED lights from Tuya, he was pleased to find they contained an ESP-12F that could easily be flashed with a different firmware. So when he ordered 30 more of them at a cost of nearly $900 USD, you can understand his frustration to find that the popular WiFi-enabled microcontroller had been swapped out for a pin-compatible clone that Tuya developed called the WB3L.

Some people would have just chalked this one up to bad luck and used the Tuya-supplied software to control their new lights, but not [konbaasiang]. Since the new chip was outwardly identical to the ESP8266, he decided to take the nuclear option and replace them with the genuine article. With a comfortable spot to work from and a nice microscope, he started on his desoldering journey.

Now it would have been nice if he could have just dropped in a real ESP-12F and called it a day, but naturally, it ended up being a bit more complex than that. The WB3L apparently doesn’t need external pull up and pull down resistors, but [konbaasiang] needed them for the swap to work. He could have come up with some kind of custom adapter PCB, but to keep things simple he decided to run a pair of through hole resistors across the top of the ESP-12F for GPIO 1/2, and use a gingerly placed SMD resistor to hold down GPIO 15.

[konbaasiang] reports that all 30 of the lights survived the transplant and are now running his own homebrew firmware. While this story had a happy ending, it’s still a cautionary tale. With a growing trend towards replacing the venerable ESP8266 with cheaper and less hacker-friendly silicon, buying IoT hardware with the intent to replace its firmware is likely to get riskier in the near future.

The Beat Goes On With This ESP32 Page Turner

April 16, 2021 by Tom Nardi 3 Comments

Looking for a hands-free way to page through sheet music on an iPad, [The_Larch] came up with this simple Bluetooth input device based on the ESP32. The microcontroller just needed to have two switches wired into the GPIO pins, in this case the same heavy-duty plungers you’d find on a guitar pedal, and a USB bulkhead pass-through to provide power. Thanks to the excellent ESP32-BLE-Keyboard library, it only took a few lines of code to fire off the appropriate key strokes when the left or right button was pressed.

While undeniably a simple project from an electronics standpoint, the wooden enclosure [The_Larch] built is an interesting change of pace from the 3D printed fare we normally see around these parts. It started life as strips of oak reclaimed from an old kitchen table, which were laminated together to make a solid block. A large spade bit was then used to bore into the block to make a void for the electronics, and a second flat piece of oak was fashioned into a front panel.

Creating Bluetooth input devices with the ESP32 is so incredibly straightforward that we’re honestly a little surprised we don’t see the trick used more often. Especially when you consider all of the custom made keyboards that have graced these pages over the last couple of years. The tools are available for anyone who wants them, so you have to wonder if hackers just aren’t fond of using Bluetooth for something as important as a keyboard?

Unmasking The Identity Of An Unusual Nintendo DS

April 16, 2021 by Tom Nardi 9 Comments

The Nintendo DS family encompasses a dizzying array of portable game systems released over a span of 17 years. The original DS received several refreshes and special editions, and when the next generation 3DS came along, it spawned a whole new collection of spin-offs. But even among all those machines there’s a name that even Mario himself would never have heard of: the Nintendo DS ML.

In a recent video, [The Retro Future] says he discovered this oddball system selling for around $25 USD on Chinese shopping site Taobao and bought one so he could get a closer look at it. Externally the system looks quite a bit like the refreshed DS Lite, but it’s notably larger and the screens look quite dated. That was already a strong hint to its true identity, as was the placement of its various buttons and controls.

Note the conspicuous absence of Nintendo’s name.

But it wasn’t until [The Retro Future] cracked the system open that he could truly confirm what he had on his hands. This was an original Nintendo DS, potentially a new old stock unit that had never been distributed, which was transplanted into a custom enclosure designed to look like one of the later upgraded models. As for what this seller meant by calling this chimera the DS ML is anyone’s guess, though one of the commenters on the video thought “Maybe Legal” had a nice ring to it.

Now assuming these really are brand new systems that were simply installed in fresh cases, $25 is arguably a good deal. So long as you aren’t concerned with playing the latest titles, anyway. But at the same time its a reminder that you get what you pay for when dealing with shady overseas sellers. It’s just as likely, perhaps even more so, that these were used systems that got spruced up to make a quick buck.

Fake components are everywhere. In fact there’s an excellent chance most of the people reading this site have received some fake parts over the years, even if they didn’t realize it at the time. When there’s fly by night companies willing to refurbish a nearly 20 year old Nintendo handheld for $25, what are the chances that Bosch actually made that $2 temperature sensor you just ordered on eBay?

Continue reading “Unmasking The Identity Of An Unusual Nintendo DS” →

Tightly Packed Raspberry Pi Tricorder Impresses

April 15, 2021 by Tom Nardi 22 Comments

We’ll say upfront that we don’t have nearly as much information about this 3D printed Star Trek: The Next Generation tricorder as we’d like. But from the image galleries [Himmelen] has posted we know it’s running on the Raspberry Pi Zero W, has a color LCD in addition to a monochrome OLED, and that it’s absolutely packed with gear.

So far, [Himmelen] has fit an NESDR RTL-SDR dongle, a GPS receiver, an accelerometer, and the battery charging circuitry in the top half of the case. Calling it a tight fit would be something of an understatement, especially when you take into account all the wires snaking around in there. But as mentioned in the Reddit thread about the device, a custom PCB backplane of sorts is in the works so all these modules will have something a little neater to plug into.

There are a lot of fantastic little details in this build that have us very excited to see it cross the finish line. The female USB port that’s been embedded into the top of the device is a nice touch, as it will make it easy to add storage or additional hardware in the field. We also love the keyboard, made up of 30 individual tact switches with 3D printed caps. It’s hard to imagine what actually typing on such an input device would be like, but even if each button just fired off its own program or function, we’d be happy.

Judging by the fact that the LCD shows the Pi sitting at a login prompt in all the images, we’re going to go out on a limb and assume [Himmelen] hasn’t gotten to writing much software for this little gadget yet. Once the hardware is done and it’s time to start pushing pixels though, something like Pygame could be used to make short work of a LCARS-style user interface that would fit the visual style of The Next Generation. In fact, off the top of our heads we can think of a few turn-key projects out there designed for creating Trek UIs, though the relatively limited computational power of the Pi Zero might be a problem.

We’ve seen several projects that tried to turn the iconic tricorder into a functional device. Some have focused on the arguably more recognizable Next Generation style such as this one, and others have targeted the more forgiving brick-shaped unit from Kirk and Spock’s era. The Wand Company is even working on a officially licensed tricorder that will supposedly be as close to we can get to the real thing with modern tech and a $250 USD price tag, though we’d wager COVID has slowed progress down on that one. In any event, whether you build it or buy it, the tricorder seems destined to become reality before too long.