Adding an External Antenna to the Raspberry Pi Zero W

Putting a complete WiFi subsystems on a single-board computer is no mean feat, and on as compact a board as the Zero W, it’s quite an achievement. The antenna is the tricky part, since there’s only so much you can do with copper traces.

The new Raspberry Pi Zero W’s antenna is pretty innovative, but sometimes you need an external antenna to reach out and touch someone. Luckily, adding an external antenna to the Zero W isn’t that tough at all, as [Brian Dorey] shows us. The Pi Zero W’s designers thoughtfully included solder pads for an ultra-miniature surface-mount UHF jack. The jack pads are placed very close to the long, curving trace that acts as a feedline to the onboard antenna. There’s even a zero ohm SMT resistor that could be repositioned slightly to feed RF to the UHF jack. A little work with a soldering iron and [Brian]’s Pi was connected to an external antenna.

[Brian] includes test data, but aside from a few outliers, the external antenna doesn’t seem to offer a huge advantage, at least under his test conditions. This speaks to the innovative design of the antenna, which [Roger Thornton] from the Raspberry Pi Foundation discussed during last week’s last week’s Hack Chat. Check out the archive for that and more.

Thanks to [theEngineer] for the tip.

WiFi Power Bar!

Ever wanted to access a file or run some program on your computer while away from home, but the darned thing is turned off? Finding themselves occasionally working away from home and not wanting to leave their computer on for extended periods, [robotmaker]’s solution was to hack into existence a WiFi-controlled power bar!

esp8266-powerbar-thumbInside the junction box, an eight-channel relay is connected to an ESP8266 module. The module uses MQTT to communicate with Home Assistant and is powered by a partially dismembered USB AC adapter — wrapped in kapon tape for safe-keeping. The entire bar is wired through a 10A fuse, while also using a fire resistant 4-gang electrical box. Once the outlets were wired in, closing it up finished up the power bar.

[robotmaker] controls the outlets via a cheap smartphone — running HADashboard — mounted to a wall with a 3D printed support. Don’t worry — they’ve set up the system to wait for the PCs to power down before cutting power, and the are also configured to boot up when the relay turns on.

The best part — the power bar only cost $25.

[via /r/homeautomation]

The Best Conference Badge Of 2017 Is A WiFi Lawn

It’s February, conference season hasn’t even started yet, and already there’s a winner of the best electronic badge of the year. For this year’s MAGfest, [CNLohr] and friends distributed 2,000 ESP8266-based swag badges.

These custom #badgelife badges aren’t. Apparently, MAGFest wouldn’t allow [CNLohr] to call these devices ‘badges’. Instead, these are ‘swadges’, a combination of swag and badges.  On board theses swadges is an ESP-12, a quartet of RGB LEDs, and buttons for up, down, left, right, A, B, Select, and Start. The swadge is powered by two AA batteries (sourced from Costco of all places), and by all accounts the badge was a complete success.

[CNLohr] is one of the great ESP8266 experts out there, and one of the design goals of this badge is to have all of these swadges communicate over raw WiFi frames. This turned out to be a great idea – using normal WiFi infrastructure with two thousand badges saturated the spectrum. The control system for was simply three badges, one per WiFi channel, that tells all the badges to change the color of the LEDs.

The swadge was a complete success, but with a few hundred blinkey glowey WiFi devices, you know [CNLohr] is going to come up with something cool. This time, he turned his lawn into a rave. About 175 swadges were laid out on the lawn, all controlled by a single controller swadge. The color of the LEDs on each swadge in the yard changes in response to the WiFi signal strength. By swinging the controller badge around his head, [CNLohr] turned his yard into a disco floor of swirling blinkieness. It looks awesome, although it might not visualize WiFi signals as well as some of [CNLohr]’s other ESP hacks.

This is a fantastic build and was well received by everyone at MAGFest. Be sure to check out the videos below, they truly show off the capabilities of this really cool piece of wearable hardware.

Continue reading “The Best Conference Badge Of 2017 Is A WiFi Lawn”

Jamming WiFi by Jumping on the ACK

As we fill our airwaves with more and more wirelessly connected devices the question of what could disrupt this systems becomes more and more important. Here’s a particularly interesting example because the proof of concept shows that you don’t need specialized hardware to pull it off. [Bastian Bloessl] found an interesting tweak to previous research that allows an Atheros WiFi card to jam WiFi by obscuring ACK frames.

The WiFi protocol specifies an Acknowledgement Frame (ACK) which is sent by the receiving device after error correction has been performed. It basically says: “yep, I got that data frame and it checks out”. This error correcting process turns out to be the key to [Bastian’s] technique as it provides time for the attack hardware to decide if it’s going to jam the ACK or not.

The jamming technique presented by [Mathy Vanhoef] at the end 2014 outlined both constant and selective jamming. The selective part involved listening for data packets and analyzing them to determine if they are headed to a MAC the attacker wishes to jam. The problem is that by the time your commodity hardware has decoded that address it’s too late to jam the packet. [Bastian] isn’t trying to jam the data frame, he’s jamming the ACK that the receiver sends back. Without that acknowledgement, the sender will not transmit any new data frames as it assumes there is a problem on the receiving end.

Increase The Range Of An ESP8266 With Duct Tape

For the longest time now, I’ve wanted to build a real, proper radio telescope. To me, this means a large parabolic reflector, a feed horn made of brass sheet, coat hanger wire, and at least for the initial experiments, an RTL-SDR dongle. I’ve done the calculations, looked at old C-band antennas on Craigslist, and even designed a mount or two that would make pointing the dish possible. I’ve done enough planning to know the results wouldn’t be great. After months of work, the best I could ever hope for is a very low-resolution image of the galactic plane. If I get lucky, there might be a bright spot corresponding to Sagittarius A.

There are better ways to build a radio telescope in your back yard, but the thought of having a gigantic parabolic dish out back, peering into the heavens, has stuck with me. I’ve even designed a dish that can be taken apart easily and transported because building your own dish is far cooler than buying a West Virginia state flower from a guy on Craigslist.

Recently, I was asked to come up with a futuristic, space-ey prop for an upcoming video. My custom-built, easily transportable parabolic antenna immediately sprang to mind. The idea of a three-meter diameter parabolic dish was rejected for something a little more practical and a little less expensive, but I did go so far as to do a few more calculations, open up a CAD program, and start work on the actual design. As a test, I decided to 3D print a small model of this dish. In creating this model, I inadvertently created the perfect WiFi antenna for an ESP8266 module using nothing but 3D printed parts, a bit of epoxy, and duct tape.

Continue reading “Increase The Range Of An ESP8266 With Duct Tape”

IoT-ify All Things: LG Has Gone Overboard

If you been following Hackaday lately, you’ve surely noticed an increased number of articles about IoT-ifying stuff. It’s a cool project to take something old (or new) and improve its connectivity, usually via WiFi, making it part of the Internet of Things. Several easy to use modules, in particular the ESP8266, are making a huge contribution to this trend. It’s satisfactory to see our homes with an ESP8266 in every light switch and outlet or to control our old stereo with our iPhone. It gives us a warm fuzzy feeling. And that’s completely fine for one’s personal projects.

But what happens when this becomes mainstream? When literally all our appliances are ‘connected’ in the near future? The implications might be a lot harder to predict than expected. The near future, it seems, starts now.

This year, at CES, LG Electronics (LG) has introduced Smart InstaView™, a refrigerator that’s powered by webOS smart platform and integrated with Amazon’s Alexa Voice Service.

… with webOS, consumers can also explore a host of WiFi-enabled features directly on the refrigerator, creating a streamlined and powerful food management system all housed directly on the front of the fridge door. Amazon’s Alexa Voice Service gives users access to an intelligent personal assistant that, in addition to searching recipes, can play music, place Prime-eligible orders from Amazon.com…

This is ‘just’ a fridge. There are other WiFi-enabled appliances by now, so what?  Apparently, during the LG press conference last Wednesday, the company marketing VP David VanderWaal said that from 2017 on, all of LG’s home appliances will feature “advanced Wi-Fi connectivity”.

Notice the word advanced, we wonder what that means? Will ‘advanced’ mean complicated? Mesh? Secure? Intelligent? Will our toaster finally break the Internet and ruin it for everyone by the end of the year? Will the other big players in the home appliances market jump in the WiFi wagon? We bet the answer is yes.

Here be dragons.

[via Ars Technica]

Rust Running on the Realtek RTL8710: ESP8266 Alternative?

For simply getting your project connected to WiFi, a least among hacker circles, nothing beats the ESP8266. But it’s not the only player out there, and we love to see diversity in the parts and languages that we use. One of the big shortcomings of the ESP8266 is the slightly-oddball Xtensa CPU. It’s just not as widely supported by various toolchains as its ARM-based brethren.

And so, when [Zach] wanted to do some embedded work in Rust, the ESP8266 was out of the picture. He turned to the RTL8710, a very similar WiFi module made by Realtek. Documentation for the RTL8710 is, at the moment, crappy, much as the ESP8266 documentation was before the hacker community had at it. But in trade for this shortcoming, [Zach] got to use the LLVM compiler, which supports the ARM architecture, and that means he can code in Rust.

In the end, the setup that [Zach] describes is a mix of FreeRTOS and some of the mbed libraries, which should be more than enough to get you up and running fairly painlessly on the chip. We’ve actually ordered a couple of these modules ourselves, and were looking to get started in straight C, but having Rust examples working doesn’t hurt, and doesn’t look all that different.

Is anyone else using the RTL8710? An ARM-based, cheap WiFi chip should be interesting.