Bad To The Bluetooth: You Shouldn’t Use This Jammer

Back in the day, an FM bug was a handy way to make someone’s annoying radio go away, particularly if it could be induced to feedback. But these days you’re far more likely to hear somebody’s Bluetooth device blasting than you are an unruly FM radio.

To combat this aural menace, [Tixlegeek] is here with a jammer for the 2.4 GHz spectrum to make annoying Bluetooth devices go silent. While it’s not entirely effective, it’s still of interest for its unashamed jankiness. Besides, you really shouldn’t be using one of these anyway, so it doesn’t really matter how well it works.

Raiding the AliExpress 2.4 GHz parts bin, there’s a set of NRF24L01+ modules that jump around all over the band, a couple of extremely sketchy-looking power amplifiers, and a pair of Yagi antennas. It’s not even remotely legal, and we particularly like the sentence “After running the numbers, I realized it would be cheaper and far more effective to just throw a rock at [the Bluetooth speaker]“. If there’s a lesson here, perhaps it is that effective jamming comes in disrupting the information flow rather than drowning it out.

This project may be illegal, but unlike some others we think it (probably) won’t kill you.

A Simple Robot For Learning About Robotics

Robots are super interesting, but you probably shouldn’t start learning about them with a full-sized industrial SCARA arm or anything. Better to learn with something smaller and simpler to understand. This simple Arduino-powered robot is called Bug, and it aims to be just that.

The design comes to us from [Joshua Stanley]. It’s based around the ubiquitous Arduino Uno, paired with a motor control and I/O shield for more connectivity. The robot uses treads for locomotion—each side has two wheels wrapped in a belt for grip. The robot has a small DC gearmotor driving each belt so it can be driven forwards, backwards, and steered differentially. To perceive the world, it uses an off-the-shelf ultrasonic transceiver module, and an NRF24L01 module for remote control. All this is wrapped up in a basic 3D-printed housing that positions the ultrasonic modules effectively as “eyes” which is kind of cute, all in all.

Despite its small size and simple construction, Bug gets around perfectly well in testing on an outdoor footpath. It even has enough torque to flip itself up at full throttle. For now, [Joshua] notes it’s a glorified remote control car, but he plans to expand it further with more functionality going forward.

We see lots of educational robots around these parts, like this nifty little robot arm. Video after the break.

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Learn About Robot Arms By Building Pedro 2.0

Whether you’re a kid or a kid at heart, learning about science and engineering can be a lot more fun if it’s practical. You could sit around learning about motors and control theory, or you could build a robot arm and play with it. If the latter sounds like your bag of hammers, you might like Pedro 2.0.

Pedro 2.0 is a simple 3D-printable robot arm intended for STEAM education. If you’re new to that acronym, it basically refers to the combination of artistic skills with education around science, technology, engineering and mathematics.

The build relies on components that are readily available pretty much around the world—SG90 servo motors, ball bearings, and an Arduino running the show. There’s also an NRF24L01 module for wireless remote control. All the rest of the major mechanical parts can be whipped up on a 3D printer, and you don’t need a particularly special one, either. Any old FDM machine should do the job just fine if it’s calibrated properly.

If you fancy dipping your toes in the world of robot arms, this is a really easy starting point that will teach you a lot along the way. From there, you can delve into more advanced designs, or even consider constructing your own tentacles. The world really is your octopus oyster.

Hacking Airline WiFi The Hard Way

We’ve all been there. You are on a flight, there’s WiFi, but you hate to pay the few bucks just to watch dog videos. What to do? Well, we would never suggest you engage in theft of service, but as an intellectual exercise, [Robert Heaton] had an interesting idea. Could the limited free use of the network be coopted to access the general internet? Turns out, the answer is yes.

Admittedly, it is a terrible connection. Here’s how it works. The airline lets you get to your frequent flier account. When there, you can change information such as your name. A machine on the ground can also see that change and make changes, too. That’s all it takes.

It works like a drop box. You take TCP traffic, encode it as fake information for the account and enter it. You then watch for the response via the same channel and reconstitute the TCP traffic from the remote side. Now the network is at your fingertips.

There’s more to it, but you can read about it in the post. It is slow, unreliable, and you definitely shouldn’t be doing it. But from the point of view of a clever hack, we loved it. In fact, [Robert] didn’t do it either. He proved it would work but did all the development using GitHub gist as the drop box. While we appreciate the hack, we also appreciate the ethical behavior!

Some airlines allow free messaging, which is another way to tunnel traffic. If you can connect to something, you can probably find a way to use it as a tunnel.

Tiny Arduino Drone Even Has An FPV Camera

In the turmoil of today’s world, drones are getting bigger, badder, and angrier. [Max Imagination] has gone the other way with his work, though, building a teeny Arduino drone that can fit in the palm of your hand. Even if you have a small hand!

The drone is based around an Arduino Pro Mini, and uses an MPU6050 IMU for motion sensing and flight control. Communication with the drone is via an NRF24L01. Four small coreless motors are used for propulsion, driven by tiny MOSFETs, and the whole assembly is run via a teeny 220 mAh lithium-polymer battery. Oh, and there’s an FPV camera so you can put on some goggles and see where it’s going!

Control is via MultiWii software, written specifically for building multirotor craft. [Max] flies the craft using a controller of his own creation, again using an NRF24L01 for communication.

It’s a neat build, and a titchy one too! Tiny drones have a character all their own, even if they can’t really stand up to windier outdoor environments. Video after the break.

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Wireless All The Things!

Neither Tom Nardi nor I are exactly young anymore, and we can both remember a time when joysticks were actually connected with wires to the computer or console, for instance. Back then, even though wireless options were on the market, you’d still want the wired version if it was a reaction-speed game, because wireless links just used to be too slow.

Somehow, in the intervening years, and although we never even really noticed the transition as such, everything has become wireless. And that includes our own hacker projects. Sure, the ESP8266 and other WiFi-capable chips made a big difference, but I still have a soft spot in my heart for the nRF24 chipset, which made at least point-to-point wireless affordable and easy. Others will feel the same about ZigBee, but the point stands: nothing has wires anymore, except to charge back up.

The reason? As this experiment comparing the latency of many different wireless connections bears out, wireless data links have just gotten that good, to the point that the latency in the radio is on par with what you’d get over USB. And the relevant software ecosystems have made it easier to go wireless as well. Except for the extra power requirement, and for cases where you need to move a lot of data, there’s almost no reason that any of your devices need wires anymore.

Are you with us? Will you throw down your chains and go wireless?

Benchmarking Latency Across Common Wireless Links For MCUs

Although factors like bandwidth, power usage, and the number of (kilo)meters reach are important considerations with wireless communication for microcontrollers, latency should be another important factor to pay attention to. This is especially true for projects like controllers where round-trip latency and instant response to an input are essential, but where do you find the latency number in datasheets? This is where [Michael Orenstein] and [Scott] over at Electric UI found a lack of data, especially when taking software stacks into account. In other words, it was time to do some serious benchmarking.

The question to be answered here was specifically how fast a one-way wireless user interaction can be across three levels of payload sizes (12, 128, and 1024 bytes). The effective latency is measured from when the input is provided on the transmitter, and the receiver has processed it and triggered the relevant output pin. The internal latency was also measured by having a range of framework implementations respond to an external interrupt and drive a GPIO pin high. Even this test on an STM32F429 MCU already showed that, for example, the STM32 low-level (LL) framework is much faster than the stm32duino one.

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