Apparently, there is a wrist-mounted device that delivers electric shocks to the wearer when it receives the appropriate command over Bluetooth. No, it’s not part of some kind of house arrest program. If you can believe it, the gadget is actually intended to help break bad habits or wake up exceptionally deep sleepers. We don’t know which of those problems [Becky Stern] has, but we’re glad to see she decided to take hers apart before the 21st century self-flagellation started.
Called the Pavlok and available for $180 USD from various online retailers, the device looks like a chunky fitness tracker. But in place of the screen that would show you how many steps you’ve taken or your current heart rate, there’s a lighting bolt button that you can press when you want to shock yourself. With the smartphone application, you can control the device remotely with a handy desktop widget that allows you to select the intensity of the shock. No, we aren’t making any of this up. Check out the video after the break to see it in action.
When [Becky] tried to take the Pavlok apart, she found that it was nearly impossible to handle it without inadvertently triggering a shock. So until she could get the case open and physically disconnect the battery, all she could do was turn the intensity down in the application and work through the occasional jolts from the device. We can only hope that more devices don’t adopt a similar sense of self-preservation.
Once inside she found mainly the same kind of hardware you’d expect in a standard, non-masochistic, fitness wearable. There’s a nRF52832 Bluetooth SoC, a MMA8451Q accelerometer, a PCF85063A I2C RTC, and a FXAS21002C gyroscope. What you’re somewhat less likely to find inside your FitBit however is the LPR6235 coupled inductor and beefy capacitors which are used to build up a high-voltage charge from the standard 3.7 V LiPo battery.
The search for the ultimate hacker’s smart watch probably won’t end any time soon. [emeryth] has nominated another possible candidate in the form of the SMA-Q2, and has made a lot of progress in making it accessible.
Also known as the SMA-TIME, the watch is based around the popular NRF52832 Bluetooth SoC, with a colour memory LCD, accelerometer, and a heart rate sensor on the back. The main feature that makes it so easy to hack is the stock bootloader on the NRF52832 that works with generic Nordic upload tool, making firmware upgrades a breeze via a smart phone. Unfortunately the bootloader itself is locked, so it must be completely wiped to gain debugging access. The hardware configuration has also been well reverse engineered with all the details available.
[emeryth] has most of the basic features working with his custom firmware, although it’s still in the early stages. He designed a new watch face that includes weather updates and basic audio controls. The 3-bit display’s power consumption has also been reduced by only refreshing the necessary parts. The heart rate sensor outputs the raw waveforms, and it’s pretty accurate after a bit of FFT and filtering magic. Built-in tap and tilt detection is available on the accelerometer, which works well, but strangely doesn’t appear to have been used in the stock firmware.
Unfortunately the original enclosure design that used screws was dropped for glued version. It’s still possible to open without breaking anything, just a bit more difficult. [emeryth] Another hardware hacker named [BigCorvus] has even designed a completely new open-source main board with a NRF52840 module and heart rate sensor on a small flex PCB, with everything up on GitHub.
[André Biagioni] is developing an open hardware bicycle navigation device called Aurora that’s so gorgeous it just might be enough to get you pedaling your way to work. This slick frame-mounted device relays information to the user through a circular array of SK6812 RGB LEDs, allowing you to find out what you need to know with just a quick glance down. No screen to squint at or buttons to press.
The hardware has already gone through several revisions, which is exactly what we’d expect to see for an entry into the 2019 Hackaday Prize. The proof of concept that [André] zip-tied to the front of his bike might have worked, but it wasn’t exactly the epitome of industrial design. It was enough to let him see that the idea had merit, and from there he’s been working on miniaturizing the design.
So how does it work? The nRF52832-powered Aurora connects to your phone over Bluetooth, and relays turn-by-turn navigation information to you via the circular LED array. This prevents you from having to fumble with your phone, which [André] hopes will improve safety. When you’re not heading anywhere specific, Aurora can also function as a futuristic magnetic compass.
With what appears to be at least three revisions of the Aurora hardware already completed by the time [André] put the project up on Hackaday.io, we’re very interested in seeing where it goes from here. The theme for this year’s Hackaday Prize is moving past the one-off prototype stage and designing something that’s suitable for production, and so far we’d say the Aurora project is definitely rising to the challenge.
If you had asked us yesterday what peak nightlight technology looked like, we might have said one of those LED panels that you stick in the outlet. At least it beats one of those little wimpy light bulbs behind the seashell, anyway. But after looking at a detailed teardown of the “Glow Light” from Casper, we’ve learned a lot about the modern nightlight. Such as the fact that there are adults who not only sleep with nightlights, but are willing to pay $89 USD for one.
On the outside they might look like marshmallows, but the insides look far more like what you’d expect from an expensive piece of consumer gear. It’s based on the Nordic nRF52832 Bluetooth SoC which is becoming an increasingly common sight in consumer gadgets, and uses an inertial measurement unit (IMU) to detect when it’s moved or twisted and adjusts the light output accordingly. If you’ve got the disposable income for two of these things, they’ll even synchronize so that twisting one will dim its counterpart.
[Uri Shaked] accidentally touched a GPIO pin on his 3.3 V board with a 12 V alligator clip, frying the board. Sound familiar? A replacement would have cost $60, which for him wasn’t cheap. Also, he needed it for an upcoming conference so time was of the essence. His only option was to try to fix it, which in the end involved a delicate chip transplant.
Fortunately, he had the good instinct to feel the metal shield over the nRF52832 immediately after the event. It was hot. Applying 3.3 V to the board now also heated up the chip, confirming for him that the chip was short-circuiting. All he had to do was replace it.
Digging around, he found another nRF52832 on a different board. To our surprise, transplanting it and getting the board up and running again took only an hour, including the time to document it. If that sounds simple, it was only in the way that a skilled person makes something seem simple. It included plenty of delicate heat gun work, some soldering iron microsurgery, and persistence with a JLink debugger. But we’ll leave the details of the operation and its complications to his blog. You can see one of the steps in the video below.
If you’ve visited a McDonald’s recently, you might have noticed something of a tonal shift. Rather than relying on angsty human teenagers to take customer orders, an increasing number of McDonald’s locations are now using self-serve kiosks. You walk up, enter your order on a giant touch screen, and then take an electronic marker with you to an open table. In mere minutes your tray of nutritiousdelicious cheap food is brought to you by… well that’s still probably going to be an angsty teenager.
The Nordic nRF52832 features a 32-bit ARM Cortex M4F processor at 64 MHz with 512 KB flash and 64 KB SRAM. Quite a bit of punch for a table marker. Incidentally, this is the same chip used in the Adafruit Feather nRF52 Pro, so there’s already an easily obtainable development toolchain.
A image of the backside of the PCB shows a wealth of labeled test points, and we imagine figuring out how to get one of these table markers doing your own bidding wouldn’t be too difficult. Not that we condone you swiping one of these things along with your Quarter Pounder with Cheese. Though we are curious to know just why they need so much hardware to indicate which table to take a particular order to; it seems the number printed on the body of the device would be enough to do that.
The quick overview of [Rich]’s method: print out the circuit with a laser printer, bake a silver-containing glue onto the surface, repeat a few times to get thick traces, glue the paper to a substrate, and use low-temperature solder to put parts together. A potential drawback is the non-negligible resistance for the traces, but a lot of the time that doesn’t matter and the nRF52 reference design proves it.
The one problem here may be the trace antenna. [Rich] reports that it sends out a weaker-than-expected signal. Any RF design folks want to speculate wildly about the cause?