bluetooth

582 Articles

Tiny ESP32 Fits Inside USB-A Connector

September 28, 2019 by 24 Comments

The ESP32 was introduced a few years ago as an inexpensive way to outfit various microcontrollers with WiFi or Bluetooth. Since then it has been experimented with and developed on, thanks to its similarities to the ESP8266 and the ability to easily program it. Watching the development of this small chip has truly been fascinating as it continues to grow. Or, in this case, shrink.

The latest development in the ESP32 world comes from [femtoduino] who, as the name suggests, makes very small things. This one is a complete ESP32 which fits inside a USB-A connector. The brains of the projects is the ESP32-D2WD which is a dual core chip with 2 Mb of memory, making it more than capable. In fact, a big part of this project was [femtoduino]’s modifications to MicroPython in order to allow it to run on this chipset. For that alone, it’s cool.

This project is impressive for both reasons, both the size and the addition to the MicroPython libraries. If you need something really really tiny, for whatever reason, you might want to look into picking up one of these. Be careful though, and be sure to get the latest version of the SDK.

Smartphone Case Doubles As Chording Keyboard, With Gesture Inputs

September 25, 2019 by 6 Comments

Smartphones and other modern computing devices are wonderful things, but for those with disabilities interacting with them isn’t always easy. In trying to improve accessibility, [Dougie Mann] created TypeCase, a combination gestural input device and chording keyboard that exists in a kind of symbiotic relationship with a user’s smartphone.

With TypeCase, a user can control a computer (or the smartphone itself) with gestures, emulate a mouse, or use the device as a one-handed chording keyboard for text input. The latter provides an alternative to voice input, which can be awkward in public areas.

The buttons and motion sensors allow for one-handed button and gestural input while holding the phone, and the Bluetooth connectivity means that the device acts and works just like a wireless mouse or keyboard. The electronics consist mainly of an Adafruit Feather 32u4 Bluefruit LE, and [Dougie] used 3D Hub’s on-demand printing service to create the enclosures once the design work was complete. Since TypeCase doubles as a protective smartphone case, users have no need to carry or manage a separate device.

TypeCase’s use cases are probably best expressed by [Dougie]’s demo video, embedded below. Chording keyboards have a higher learning curve, but they can be very compact. One-handed text input does remind us somewhat of a very different approach that had the user make gestures in patterns reminiscent of Palm’s old Graffiti system; perhaps easier to learn but not nearly as discreet.

Continue reading “Smartphone Case Doubles As Chording Keyboard, With Gesture Inputs” →

Over-Engineered Cat Door Makes Purrfect Sense

September 16, 2019 by 21 Comments

On paper, pet doors are pretty great. You don’t have to keep letting the cat in and out, and there should be fewer scratches on the door overall. Unfortunately, your average pet door is indiscriminate, and will let any old creature waltz right in. Well, [Jeremiah] was tired of uninvited critters, so he built a motorized door with a built-in bouncer. Now, only animals with pre-approved BLE tags can get in.

The bouncer is a Raspi 3 running Node-RED, which scans continuously for BLE advertisements from the cats’ collars. [Jeremiah] settled on Tile tags because they’re reliable and cat-proof. The first version used an Arduino and RFID tags for the cats, but they had to get too close to the door to trigger it.

We love [Jeremiah]’s choice of door actuator, a 12V retractable car antenna. [Jeremiah] uses the antenna itself to lift and lower the removable lockout panel that comes with the door. He removed the circuit that retracts the antenna when power is lost, so that power outages don’t become free-for-alls for shelter-seeking animals.

There’s also a nice feature for slow creatures—the door won’t close until 15 seconds after the last BLE ad, so they cats won’t ever have to Indiana Jones it through the opening. Magnetic switches currently limit the door travel at the top and bottom, though [Jeremiah] will eventually replace them with standard switches. Paw at the break until you get a walk-through video.

Cats will be cats, and the ones that go outside will probably rack up a body count. Here’s a cat door that looks for victims clenched between cat jaws and starts a 15-minute lockout period.

Continue reading “Over-Engineered Cat Door Makes Purrfect Sense” →

The Amazon Dash Button: A Retrospective

August 27, 2019 by 38 Comments

The Internet of Things will revolutionize everything! Manufacturing? Dog walking? Coffee bean refilling? Car driving? Food eating? Put a sensor in it! The marketing makes it pretty clear that there’s no part of our lives which isn’t enhanced with The Internet of Things. Why? Because with a simple sensor and a symphony of corporate hand waving about machine learning an iPhone-style revolution is just around the corner! Enter: Amazon Dash, circa 2014.

The first product in the Dash family was actually a barcode scanning wand which was freely given to Amazon Fresh customers and designed to hang in the kitchen or magnet to the fridge. When the Fresh customer ran out of milk they could scan the carton as it was being thrown away to add it to their cart for reorder. I suspect these devices were fairly expensive, and somewhat too complex to be as frequently used as Amazon wanted (thus the extremely limited launch). Amazon’s goal here was to allow potential customers to order with an absolute minimum of friction so they can buy as much as possible. Remember the “Buy now with 1-Click” button?

That original Dash Wand was eventually upgraded to include a push button activated Alexa (barcode scanner and fridge magnet intact) and is generally available. But Amazon had pinned its hopes on a new beau. Mid 2015 Amazon introduced the Dash Replenishment Service along with a product to be it’s exemplar – the Dash Button. The Dash Button was to be the 1-Click button of the physical world. The barcode-scanning Wands require the user to remember the Wand was nearby, find a barcode, scan it, then remember to go to their cart and order the product. Too many steps, too many places to get off Mr. Bezos’ Wild Ride of Commerce. The Dash Buttons were simple! Press the button, get the labeled product shipped to a preconfigured address. Each button was purchased (for $5, with a $5 coupon) with a particular brand affinity, then configured online to purchase a specific product when pressed. In the marketing materials, happy families put them on washing machines to buy Tide, or in a kitchen cabinet to buy paper towels. Pretty clever, it really is a Buy now with 1-Click button for the physical world.

There were two versions of the Dash button. Both have the same user interface and work in fundamentally the same way. They have a single button (the software can recognize a few click patterns), a single RGB LED (‘natch), and a microphone (no, it didn’t listen to you, but we’ll come back to this). They also had a WiFi radio. Version two (silently released in 2016) added Bluetooth and completely changed the electrical innards, though to no user facing effect.

In February 2019, Amazon stopped selling the Dash Buttons. Continue reading “The Amazon Dash Button: A Retrospective” →

This Week In Security: KNOB, Old Scams Are New Again, 0-days, Backdoors, And More

August 23, 2019 by 12 Comments

Bluetooth is a great protocol. You can listen to music, transfer files, get on the internet, and more. A side effect of those many uses is that the specification is complicated and intended to cover many use cases. A team of researchers took a look at the Bluetooth specification, and discovered a problem they call the KNOB attack, Key Negotiation Of Bluetooth.

This is actually one of the simpler vulnerabilities to understand. Randomly generated keys are only as good as the entropy that goes into the key generation. The Bluetooth specification allows negotiating how many bytes of entropy is used in generating the shared session key. By necessity, this negotiation happens before the communication is encrypted. The real weakness here is that the specification lists a minimum entropy of 1 byte. This means 256 possible initial states, far within the realm of brute-forcing in real time.

The attack, then, is to essentially man-in-the-middle the beginning of a Bluetooth connection, and force that entropy length to a single byte. That’s essentially it. From there, a bit of brute forcing results in the Bluetooth session key, giving the attacker complete access to the encrypted stream.

One last note, this isn’t an implementation vulnerability, it’s a specification vulnerability. If your device properly implements the Bluetooth protocol, it’s vulnerable.

CenturyLink Unlinked

You may not be familiar with CenturyLink, but it maintains one of the backbone fiber networks serving telephone and internet connectivity. On December 2018, CenturyLink had a large outage affecting its fiber network, most notable disrupting 911 services for many across the United States for 37 hours. The incident report was released on Monday, and it’s… interesting.
Continue reading “This Week In Security: KNOB, Old Scams Are New Again, 0-days, Backdoors, And More” →

Perfecting A Bluetooth N64 Controller

August 17, 2019 by 1 Comment

Love it or hate it, the Nintendo 64 controller doesn’t seem to be going anywhere. Dedicated fans are still looking for ways to use the unique trilobed controller with modern systems, and they won’t be satisfied until they perfectly replicate the original experience. [Shyri Villar] has been working on perfecting a blend of original and modern hardware that looks very promising.

The project started when [Shyri] found that you could take the internals from a modern third party Bluetooth N64 controller made by 8BitDo and put them into the original controller’s case. This would give you the original buttons back, and overall a more authentic weight and feel. Unfortunately, this usually means dumping the original N64 joystick for the 8BitDo’s.

What [Shyri] wanted to do was install the 8BitDo PCB into an original N64 controller, but adapt Nintendo’s joystick to communicate with it. Unfortunately, since the original joystick used optical encoders and the 8BitDo version uses potentiometers, there’s something of a language gap.

To bridge the divide, both the X and Y dimensions of the joystick get their own PIC12F675 microcontroller and X9C103S digital potentiometer. The microcontrollers read the X and Y values from the original joystick’s encoders, and use the digital potentiometers to provide the 8BitDo with the expected analog input. Right now the electronics are held on two scraps of perfboard tucked into the side “wings” of the controller, but hopefully we’ll see a custom PCB in the future.

If you’re more interested in going back in time with your trusty N64 controller, then you might be interested in learning more about how one hacker managed to hook it up to the MSX.

Broken HP-48 Calculator Reborn As Bluetooth Keyboard

August 16, 2019 by 8 Comments

Considering their hardware specification, graphing calculators surely feel like an anachronism in 2019. There are plenty of apps and other software available for that nowadays, and despite all preaching by our teachers, we actually do carry calculators with us every day. On the other hand, never underestimate the power of muscle memory when using physical knobs and buttons instead of touch screen or mouse input. [epostkastl] combined the best of both worlds and turned his broken HP-48 into a Bluetooth LE keyboard to get the real feel with its emulated counterpart.

Initially implemented as USB device, [epostkastl] opted for a wireless version this time, and connected an nRF52 based Adafruit Feather board to the HP-48’s conveniently exposed button matrix pins. For the software emulation side, he uses the Emu48, an open source HP calculator emulator for Windows and Android. The great thing about Emu84 is that it supports fully customizable mappings of regular keyboard events to the emulated buttons, so you can easily map, say, the cosine button to the [C] key. The rest is straight forward: scanning the button matrix detects button presses, maps them to a key event, and sends it as a BLE HID event to the receiving side running Emu84.

As this turns [epostkastl]’s HP-48 essentially into a regular wireless keyboard in a compact package — albeit with a layout that outshines every QWERTY vs Dvorak debate. It can of course also find alternative use cases, for examples as media center remote control, or a shortcut keyboard. After all, we’ve seen the latter one built as stomp boxes and from finger training devices before, so why not a calculator?

Continue reading “Broken HP-48 Calculator Reborn As Bluetooth Keyboard” →