Wireless Protocol Reverse Engineered To Create Wrist Wearable Mouse

March 10, 2018 by 7 Comments

We’ve seen a few near-future sci-fi films recently where computers respond not just to touchscreen gestures but also to broad commands, like swiping a phone to throw its display onto a large flat panel display. It’s a nice metaphor, and if we’re going to see something like it soon, perhaps this wrist-mounted pointing device will be one way to get there.

The video below shows the finished product in action, with the cursor controlled by arm movements. Finger gestures that are very much like handling a real mouse’s buttons are interpreted as clicks. The wearable has a Nano, an MPU6050 IMU, and a nRF24L01 transceiver, all powered by some coin cells and tucked nicely into a 3D-printed case. To be honest, as cool as [Ronan Gaillard]’s wrist mouse is, the real story here is the reverse engineering he and his classmate did to pull this one off.

The road to the finished product was very interesting and more detail is shared in their final presentation (in French and heavy with memes). Our French is sufficient only to decipher “Le dongle Logitech,” but there are enough packet diagrams supporting into get the gist. They sniffed the packets going between a wireless keyboard and its dongle and figured out how to imitate mouse movements using an NRF24 module. Translating wrist and finger movements to cursor position via the 6-axis IMU involved some fairly fancy math, but it all seems to have worked in the end, and it makes for a very impressive project.

Is sniffing wireless packets in your future? Perhaps this guide to Wireshark and the nRF24L01 will prove useful.

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IoT Potty Training

March 10, 2018 by 22 Comments

If you have not had children, stop reading now, we implore you. Because before you’ve had kids, you can’t know how supremely important it is that they take care of going to the bathroom by themselves. [David Gouldin] knows how it is. But unlike most of us, he resorted to using an Amazon IoT button and Twilio. No, we are not kidding.

The problem he was trying to solve is when his younger child would need to use the potty in the middle of the night, calling out for assistance would wake the older child. [David] said it best himself:

Behind the smiling emoji facade is an Amazon IoT button, a variant of Amazon’s dash button. When my kid presses this button, it triggers an AWS Lambda function that uses Twilio’s Python Helper Library to call my iPhone from a Twilio number. The Twilio number is stored in my contacts with “emergency bypass” turned on, so even when it’s 2am and I’m on “do not disturb” I still get the call.

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High-Effort Streaming Remote For Low-Effort Bingeing

March 10, 2018 by 7 Comments

There’s no limit to the amount of work some people will put into avoiding work. For instance, why bother to get up from your YouTube-induced vegetative state to adjust the volume when you can design and build a remote to do it for you?

Loath to interrupt his PC streaming binge sessions, [miroslavus] decided to take matters into his own hands. When a commercially available wireless keyboard proved simultaneously overkill for the job and comically non-ergonomic, he decided to build a custom streaming remote. His recent microswitch encoder is prominently featured and provides scrolling control for volume and menu functions, and dedicated buttons are provided for play controls. The device reconfigures at the click of a switch to support Netflix, which like YouTube is controlled by sending keystrokes to the PC through a matching receiver. It’s a really thoughtful design, and we’re sure the effort [miroslavus] put into this will be well worth the dozens of calories it’ll save in the coming years.

A 3D-printed DIY remote is neat, but don’t forget that printing can also save a dog-chewed remote and win the Repairs You Can Print contest.

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A Faster Grave Digger For Your Child

March 10, 2018 by 12 Comments

Children love speed, but so few of those electric ride on toys deliver it. What’s a kid to do? Well, if [PoppaFixit]’s your dad, you’re in luck.

This project starts with an unusually cool Power Wheels toy, based on the famous Grave Digger monster truck. During the modification process, it was quickly realised that the original motor controller wasn’t going to cut the mustard. With only basic on/off control, it gave a very jerky ride and was harsh on the transmission components, too. [PoppaFixit] decided to upgrade to an off-the-shelf 24 V motor controller to give the car more finesse as well as speed. The controller came with a replacement set of pedals, both accelerator and brake, to replace the stock units. On the motor side, a couple of beefier Traxxas units were substituted for the weedy originals.

Acceleration is now much improved, not just due to the added power, but because the variable throttle allows the driver to avoid wheelspin on hard launches. It also makes the car much more comfortable and safe to drive, thanks to the added controllability. Another way to tell the project was a success is the look of pure joy on the new owner’s face!

This was a fairly basic install, very accessible to the novice. These sort of electric vehicle hop-ups are commonplace enough that there are a wide variety of suppliers who sell easy-to-use kits for this sort of work. For that reason, we’ve seen plenty of hacks of this sort – like this modified scooter, or these Power Wheels set up for racing.

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Secret Book Light Switch

March 10, 2018 by 9 Comments

You enter a study and see a lightbulb hanging on the bookshelf. You try all the switches in the room — nothing is turning it on. Remembering you’re in [lonesoulsurfer]’s home, you realize that you’re going to have to start yanking on every book in sight.

While often associated with the likes of Bat-caves and other complicated hidden passageways, turning a shelved book into a secret switch isn’t complex in its own right. [lonesoulsurfer] is basing their build on one by B.Light Design revolving around a fan switch, some aluminium strips, a block terminal, fishing line, a hinge, and — of course — a book with a dust jacket and something to trigger.

Bend the aluminium into an angle bracket and drill a hole to attach the fan switch — ensuring the whole is small enough to fit behind and not distinguish the book you’re using. Cutting the hinge to the size of the book and screwing a strip of aluminium to it, both this lever and the fan switch’s bracket are then mounted on the shelf. Once a length of fishing twine is tethered to the lever and fitted through the book’s pages to the fan switch — ensuring the line is taut — sliding the dust jacket back onto the book completes the disguised switch!

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You Don’t Need To Be Tony Stark To Afford This Hand Controller

March 9, 2018 by 4 Comments

Proving that duct tape really can do anything, [StudentBuilds] uses it to make a workable controller out of a glove. To be fair, there are a few more bits too, including paper coated with pencil graphite and tin foil, which forms a variable resistor you can read with an Arduino analog input. You can see the entire thing in the video below.

The source code is simple at this point — eventually, he plans to control a robotic hand with the controller, but that’s later. However, there’s no promised link to the code in the description, so you’ll have to freeze frame and type. However, it is pretty simple — just read the analog pin values to determine the specific values for each finger.

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An Autonomous Drone For Working Rare Squares

March 9, 2018 by 20 Comments

Amateur radio is an extremely broad church when it comes to the numerous different activities that it covers. Most of the stories featuring radio amateurs that we cover here have involved home-made radios, but that represents a surprisingly small subset of licence holders.

One activity that captivates many operators is grid square collecting. The map is divided into grid squares, can you make contact with all of them? Land-based squares in Europe and North America are easy, those in some more sparsely populated regions a little less so, and some squares out in the ocean are nigh-on impossible. As an attempt to solve this problem, the Jupiter Research Foundation Amateur Radio Club have put an HF transceiver and associated electronics in a WaveGlider autonomous seagoing vehicle. The idea is that it will traverse the ocean, and you can work it, thus getting the contact you require to add those rarest of grid squares to your list.

The transceiver in question is a commercial portable one, an Elecraft KX3, and the brain of the payload is a Raspberry PI. It’s operating the FT8 mode, and will respond to a call on 14074 kHz in an automated fashion (Or it would, were its status page not telling us that it is offline due to power issues). It’s currently somewhere in the Pacific ocean, having been at sea now for a couple of months.

We spotted this through a spirited online discussion as to whether working an automated station is really a proper contact at all, with one amateur commenting that it might be a way for him to keep on going post mortem. But the ethics of the contact aside, it’s an extremely interesting project and one we hope eventually will come back online.

Thanks Sotabeams, via [AE5X].