The ARRL Raises A Stink About Illegal FPV Transmitters

We have all been beneficiaries of the boom in availability of cheap imported electronics over the last decade. It is difficult to convey to someone under a certain age the step change in availability of parts and modules that has come about as a result of both the growth of Chinese manufacturing and Internet sales that allow us direct access to sellers we would once only have found through a lengthy flight and an intractable language barrier.

So being able to buy an ESP8266 module or an OLED display for relative pennies is good news, but there is a downside to this free-for-all. Not all the products on offer are manufactured to legal standards wherever in the world we as customers might be, and not all of them are safe to use. We’ve all seen teardowns of lethal iPhone charger knock-offs, but this week the ARRL has highlighted an illegal import that could take being dangerous to a whole new level as well as bring an already beleaguered section of our community to a new low.

The products the radio amateurs are concerned about are video transmitters that work in the 1.2GHz band. These are sold for use with FPV cameras on multirotors, popularly referred to as drones, and are also being described as amateur radio products though their amateur radio application is minimal. The ARRL go into detail in their official complaint (PDF) about how these devices’ channels sit squarely over the frequencies used by GLONASS positioning systems, and most seriously, the frequencies used by the aircraft transponders on which the safety of our air traffic control system relies.

The multirotor community is the unfortunate recipient of a lot of bad press, most of which is arguably undeserved and the result of ignorant mass media reporting. We’ve written on this subject in the past, and reported on some of the proposals from governments which do not sound good for the enthusiast. It is thus a huge concern that products like those the ARRL is highlighting could result in interference with air traffic, this is exactly not the association that multirotor fliers need in a hostile environment.

The ARRL complaint highlights a particular model with a 5W output, which is easily high enough to cause significant interference. It is however just one of many similar products, which a very straightforward search on the likes of AliExpress or eBay will find on sale for prices well under $100. So if you are concerned with multirotors we’d urge you to ensure that the FPV transmitters you or your friends use are within the legal frequencies and power levels. We’re sure none of you would want an incident involving a manned aircraft on your conscience, nor would you relish the prospect of the encounter with law enforcement that would inevitably follow.

In the past we’ve taken a look at some of the fuss surrounding reported drone incidents, and brought you news of an Australian sausage lover in hot water for drone-based filming. It’s a hostile world out there, fly safe!


Filed under: news, radio hacks

Raspberry Pi Launches Compute Module 3

The forgotten child of the Raspberry Pi family finally has an update. The Raspberry Pi Compute Module 3 has been launched.

The Pi 3 Compute Module was teased all the way back in July, and what we knew then is just about what we know now. The new Compute Module is based on the BCM2837 processor – the same as found in the Raspberry Pi 3 – running at 1.2 GHz with 1 gigabyte of RAM. The basic form factor SODIMM form factor remains the same between the old and new Compute Modules, although the new version is 1 mm taller.

The Compute Module 3 comes with four gigabytes of eMMC Flash and sells for $30 on element14 and RS Components. There’s also a cost-reduced version called the Compute Module 3 Light that forgoes the eMMC Flash and instead breaks out those pins to the connector, allowing platform integrators to put an SD card or Flash chip on a daughter (mother?) board. The CM3 Lite version sells for $25.

The Compute Module was always the black sheep of the Raspberry Pi family, although it did find a few applications in its desired use case. The Raspberry Pi Foundation heralded NEC’s announcement of a line of large-format displays using the Compute Module recently. The OTTO, from Next Thing Co., makers of the C.H.I.P. single board computer, also had a Pi Compute Module shoved in its brain. Whether or not companies will choose the Compute Module 3 as a platform remains up in the air, but the value proposition is there; the Pi 3 is a vastly superior computational platform compared to the Pi 1. Putting this power on an easy-to-use module will make for some very interesting products.

If you’re looking for a really cool project for the Compute Module 3, I would suggest a cluster of Pis. The problem with a cluster of Compute Modules is that nearly all SODIMM sockets are horizontal, and for maximum efficiency, you’ll want a vertical header. The good news is vertical SODIMM headers do exist, and you can buy 20% of the world’s supply of these headers for about $500. I know because I did.


Filed under: news, Raspberry Pi

A Simple Route To A Plug Top Pi

There are a host of tiny plug-top computers available for the experimenter who requires an all-in-one mains-powered computing platform without the annoyance of a full-sized PC or similar. But among the various models there has always been something missing, a plug-top Raspberry Pi. To address that gap in the market, [N-O-D-E] has created a fusion of Pi and plug using the official Raspberry Pi PSU accessory and a Raspberry Pi Zero, with a UUGear Zero4U USB hub sandwiched between the two.

It’s a pretty straightforward and simple build, the back of the PSU is formed into a flat surface with a bit of Sugru, then the power cable is stripped back to its wires which are then connected to the power pins on the USB hub. The hub is then attached to the Sugru — he doesn’t say how, but we suspect double-sided tape — and the Pi is mounted on top of the hub. Pogo pins make the required connections to the pads on the underside of the computer, so it can be removed and replaced at will.

The result is a useful addition to your Pi arsenal, one that could be used for a host of little stand-alone devices. It could use a cover, however we suspect a 3D printer owner could create themselves one with relative ease. The full description is shown in the video below the break.

Fitting Raspberry Pis into small spaces is a favorite theme, we’ve had a Zero in a projector and another in a USB stick. Perhaps it’s the miniature Pi 2 laptop that takes the prize though.


Filed under: Raspberry Pi

An Intel 8085 Microprocessor Trainer

The Intel 8085 microprocessor was introduced 40 years back, and along with its contemporaries — the Z80 and the 6502 — is pretty much a dinosaur in terms of microprocessor history. But that doesn’t stop it from still being included in the syllabus for computer engineering students in many parts of the world. The reason why a 40 year old microprocessor is still covered in computer architecture text books instead of computer history is a bit convoluted. But there’s a whole industry that thrives on the requirements of college laboratories and students requiring “8085 Microprocessor Training Kits”. [TisteAndii] just finished college in Nigeria, where these kits are not locally built and need to be imported, usually costing well over a 100 dollars.

Which is why his final year project was a low cost Intel 8085 Microprocessor Trainer. It’s a minimalist design with some basic read/write memory, program execution and register inspection, with no provision for single stepping or interrupts yet. The monitor program isn’t loaded in an EEPROM. Instead, a PIC18 is used and connected to the 8085 address, data and control pins. This makes it easier to write a monitor program in C instead of assembly. And allows use of a 1.8″ LCD with SPI interface instead of the more usual 7-segment displays used for these kind of kits. [TisteAndii] built a 6×4 keyboard for input, but couldn’t solve debounce issues and finally settled on a 5×4 membrane keypad.

Being a rookie, he ended up with a major flaw in his board layout — he missed connecting the SRAM and the PPI devices to the data bus. A bunch of jumper links seemed to solve the issue, but it wasn’t perfect. This, and a few other problems gave him a lot of grief, but towards the end, it all worked, almost. Most importantly, his BoM cost of about $35 makes it significantly cheaper compared to the commercial units available in Nigeria.

While some hackers may consider this a trivial project, it solves a local problem and we hope the next iteration of the design improves the kit and makes it more accessible.


Filed under: computer hacks

Alexa Keeps Pet Snake Thermoregulated

[Chris Grill] got his hands on a pet boa constrictor, which requires a fairly strict temperature controlled environment. Its enclosure needs to have a consistent temperature throughout, or the snake could have trouble regulating its body temperature. [Chris] wanted to keep tabs on the temp and grabbed a few TTF-103 thermistors and an Arduino Yun, which allowed him to log the temperature on each side of the enclosure. He used some code to get the temp reading to the linux side of an Arduino Yun, and then used jpgraph, a PHP graphing library, to display the results.

snakemainBut that wasn’t good enough. Why not get a little fancy and have Amazon’s Echo read the temps back when you ask! Getting it setup was not so bad thanks to Amazon’s well documented steps to get custom commands set up.

He eventually lost the battle to get the Echo to talk to the web server on the Yun due to SSL issues, but he found an existing workaround by using a proxy.


Filed under: Arduino Hacks

Hackaday Links: January 15, 2017

What’s more expensive than a car and a less useful means of transportation? A 747 flight simulator built in a basement. There’s a project page where a few more details are revealed. There’s a 180 degree wrap-around screen for the main display, a glass cockpit, and the controls and gauges are ‘good enough’ to feel like the real thing. The simulator is running a highly customized version of FS9 (Microsoft’s flight sim from the year 2004).

For the last few years, Google has been experimenting with high altitude balloons delivering Internet to remote populations. This is Project Loon, and simply by the fact that Google hasn’t shuttered this Alpha-bit, we can assume the project is a success. A Project Loon balloon recently crashed in Panama, which means we can get an up-close look at the hardware. These balloon base stations are a lot bigger than you would think.

We’ve seen beautiful PCBs before, but [Blake] is taking this to another level entirely. He’s developed a process to convert bitmaps into files suitable to send to a PCB manufacturer. The results are… strange, and very cool. Check out a video of the process here.

If you want to dial out from behind the great firewall of China, you’re probably going to use a VPN. Here’s an idea that doesn’t work as well as a VPN. Use an acoustic coupler with your iPhone. Will it work? Of course it will – modems have been standardized for fifty years. Will it work well? No, I can speak faster than 300 baud.

Do you sell on Tindie? We have a dog park. Tindie sellers around the world will be meeting up on Hackaday.io next Friday to discuss Tindie and Tindie-related activities. Join in!

A quick aside relating to Hackaday and Tindie swag. 1) The Tindie dog as a stuffed animal. 2) A Hackaday logo t-shirt where the skull is decorated like a Día de Muertos sugar skull. Pick one, leave your response in the comments.


Filed under: Hackaday Columns, Hackaday links

Shmoocon 2017: A Simple Tool For Reverse Engineering RF

Anyone can hack a radio, but that doesn’t mean it’s easy: there’s a lot of mechanics that go into formatting a signal before you can decode the ones and zeros.

At his Shmoocon talk, [Paul Clark] introduced a great new tool for RF Reverse Engineering. It’s called WaveConverter, and it is possibly the single most interesting tool we’ve seen in radio in a long time.

If you wanted to hack an RF system — read the data from a tire pressure monitor, a car’s key fob, a garage door opener, or a signal from a home security system’s sensor — you’ll be doing the same thing for each attack. The first is to capture the signal, probably with a software defined radio. Take this data into GNU Radio, and you’ll have to figure out the modulation, the framing, the encoding, extract the data, and finally figure out what the ones and zeros mean. Only that last part, figuring out what the ones and zeros actually do, is the real hack. Everything before that is just a highly advanced form of data entry and manipulation.

[Paul]’s WaveConverter is the tool built for this data manipulation. Take WaveConverter, input an IQ file of the relevant radio sample you’d like to reverse engineer, and you have all the tools to turn a radio signal into ones and zeros at your disposal. Everything from determining the preamble of a signal, figuring out the encoding, to determining CRC checksums is right there.

All of this is great for reverse engineering a single radio protocol, but it gets even better. Once you’re able to decode a signal in WaveConverter, it’s set up to decode every other signal from that device. You can save your settings, too, which means this might be the beginnings of an open source library of protocol analyzers. If someone on the Internet has already decoded the signals from the keyfob of a 1995 Ford Taurus, they could share those settings to allow you to decode the same keyfob. This is the very beginnings of something very, very cool.

The Github repo for WaveConverter includes a few sample IQ files, and you can try it out for yourself right now. [Paul] admits there are a few problems with the app, but most of those are UI changes he has in mind. If you know your way around programming GUIs, [Paul] would appreciate your input.


Filed under: cons, radio hacks

Garage Door Opener Logs to Google Drive

A garage door opener is a pretty classic hack around these parts. IR, Bluetooth, WiFi, smartphone controlled, web interfaces — we’ve seen it all.  But if you want to keep track of people going in and out, you need some way of logging what’s happening. You could go ahead and roll up your own SQL based solution, tied into a custom web page. But there’s an easier way; you can build a garage door opener that logs events to Google Drive.

[WhiskeyTangoHotel] was looking for an ESP8266 project, and a garage door opener seemed just the ticket. It’s simple enough to code up, and control over WiFi comes in handy. Interfacing with the garage door was simple enough — the existing opener uses a simple push button, which is easily controlled by wiring up a relay to do the job. Logging is as simple as having the ESP8266 send requests to IFTTT which is set up to make posts to a Google Sheet with status updates.

The project is fairly basic, but there’s room for expansion. By using separate Maker Channel triggers on IFTTT, different users of the garage door could be tracked. It would also be easy to add some limit switches or other sensors to detect the door’s position, so it can be determined whether the door was opened or closed.

There’s always another take on the garage door opener — check out this hack that opens the garage door in response to flashing headlights.


Filed under: home hacks

Innocent TV Imprisoned Behind Mirror

After following along with all the Magic Mirror builds, [Troy Denton] finally caved in and started building one for his girlfriend for Christmas. These popular builds are all pretty much bespoke, and this one is no different.

mirror2His victim TV didn’t have the ability to be switched on and off by the Raspberry Pi using HDMI/CEC, so he came up with an alternative. He got a couple of opto-isolators and soldered one to the on/off button on the TV’s control board. The Pi didn’t know whether it was switching the TV on or off, it just knew it was switching it. To solve this, [Troy Denton] connected another opto-isolator to the TV’s LED, this one the other way around. When the TV is turned on, the Pi now detects it.

The enclosure is fabbed from 2×4 lumber, the mirror is one-way acrylic which runs somewhere in the $75-100 range for this 27-9/16″x15-1/2″ application. The top and bottom rails include lines of holes to encourage airflow to keep things cool. the face plate is picture framing which makes it easy to mount the mirror. An ultrasonic range finder finishes off the build and when someone stands in front of this magic mirror, the Pi senses it and turns the monitor on.

Included in [Troy]’s post are the Python code and shell scripts he wrote as well as a bunch of pictures of the build process. We’ve seen Magic Mirrors builds before, including some small ones. They’re a cool addition to the house and a fairly simple build.


Filed under: hardware, Raspberry Pi

Fixing Bugs In A 37 Year Old Apple II Game

Emulators are a great way to reminisce about games and software from yesteryear. [Jorj Bauer] found himself doing just that back in 2002, when they decided to boot up Three Mile Island for the Apple II. It played well enough, but for some reason, crashed instantly if you happened to press the ‘7’ key. This was a problem — the game takes hours to play, and ‘7’ is the key for saving and restoring your progress. In 2002, [Jorj] was content to put up with this. But finally, enough was enough – [Jorj] set out to fix the bug in Three Mile Island once and for all.

The project is written up in three parts — the history of how [Jorj] came to play Three Mile Island and learn about Apple IIs in the first place, the problem with the game, and finally the approach to finding a solution. After first discovering the problem, [Jorj] searched online to see if it was just a bad disk image causing the problem. But every copy they found was the same. There was nothing left for it to be but problem in the binary.

title-screen
The revised title screen, with bugfix noted.

It’s a tale of disassembly and dredging though decades-old scanned literature. The key to the bug was found in a copy of the Micro 6502 Journal from June 1980. If you don’t want the story spoiled, stop here — the problem came about when someone copied an Apple DOS 3.1 version of the game to an Apple DOS 3.3 disk. The disk formats aren’t backwards compatible, so the 3.3 disk version would only play on a DOS 3.3 machine. However, the game’s code uses bytecodes in the save routine that refer to DOS 3.1 functions that had changed in DOS 3.3. It was by searching for this bytecode that the journal popped up on Google with a hint. The article mentions the changes in bytecodes between DOS versions, giving [Jorj] the clue he needed to solve the mystery.

In the end, to get the game to function properly under DOS 3.3, all that was required was to change the code to point to the proper register for DOS 3.3. With this done, the finishing touch was a modified title screen highlighting [Jorj]’s hard work. Credit where credit is due.

Kindly, [Jorj] has uploaded the fixed game for the world to enjoy (.gz file download)! It’s always great to see people still working with and enjoying these old systems. The Apple IIGS even got itself an OS update at age 29.


Filed under: classic hacks, macs hacks