Wireless Hacks

1050 Articles

Building A LoRa PHY With SDR

November 18, 2016 by 6 Comments

The Internet of Things is terrible when it’s your toaster. The real fun happens when you have hundreds or thousands of sensors sending data back to a base station every day. That requires low power, and that means LPWAN, the Low Power Wide Area Network.

There are a lot of options for LPWAN, but few are a perfect fit. LoRa is one of the rare exceptions, offering years of operation on a single AA cell, and range measured in miles. Layers two and three of LoRa are available as public documentation, but until now layer one has been patented and proprietary. At the GNU Radio Conference, [Matt Knight] gave a talk on reverse engineering the LoRa PHY with a software defined radio. Now, LoRa is open to everyone, and anyone can decode the chirps transmitted from these tiny, low power devices.

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Slow 3.5″ Raspberry Pi LCD Hacked To 40 MHz With ESP8266

November 17, 2016 by 18 Comments

As microcontrollers become more and more common, we see more ways to get a lot of performance out of one chip. A great example of this was the ESP8266 which was originally seen as a cheap WiFi card but has since blossomed into its own dev platform thanks to the horsepower hidden within. To that end, [Martin] is trying to push the now-ubiquitous WiFi chip even further by rolling out his own LCD driver for it from scratch.

The display of choice is the KeDei LCD 3.5″ module which was originally intended for use with a Raspberry Pi. [Martin] points out that this display isn’t optimized for speed, but after everything is said and done he has its clock line running at 40 MHz. To get this kind of speeds from the LCD, he depopulates the first shift register and adds his own fast-propagation circuit to establish a more-traditional serial addressing mode. With use of a WLCD driver that [Martin] also wrote, it is now relatively easy to draw on the screen very quickly with an ESP module. Check it out in the video below.

If you’re looking for your own tiny, cheap, fast display, this is one cool way to do it but we would suggest spinning a carrier board for both the ESP and the added circuitry. We’re looking forward to future projects which puts devices like these inside of really tiny magic mirrors, or uses them in other places where a small graphical display would be handy.

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ESP8266 Lullaby

November 11, 2016 by 22 Comments

The ESP8266 is certainly a versatile device. It does, however, draw a bit of power. That isn’t really surprising, though, since you would expect beaming out WiFi signals to take a little juice. The trick is to not keep the device on all the time and spend the rest of the time in deep sleep mode. [Marco Schwartz] has a good tutorial about how to use this mode to run for “years” on a battery.

[Marco] notes that even using a 2500 mAh LiPo battery, he only gets about 30 hours of operation without sleep. By putting the chip in sleep mode, the current consumption drops from about 88 mA to just over 8 mA. That’s still high, though, because the board has a power LED! By removing a jumper or cutting a trace (depending on the board), you can drop the current draw to about 0.08 mA (80 uA) when it’s not doing anything.

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Web Matrix Control Proves Power Of ESP8266

November 1, 2016 by 4 Comments

LED matrix projects are all over the place, but this one is interesting for its simplicity: it’s an LED matrix that is driven straight from an ESP8266 board. [Ray] put it together as a quick project for his students to teach the basics of LED programming.

It’s built using a WS2812 LED matrix board he designed himself and his own ESPToy ESP8266 dev board. But the gist of the hardware is simply an ESP8266 and some WS2812’s. Where this gets interesting is with the user interaction side of things. The ESP makes WiFi and web serving easy, and [Ray] has build a simple HTTP GET API into the firmware. This is a great combination for the web dashboard and JavaScript-based animation programs [Ray] is demonstrating in the video below.

Just get on the same network and load up the module’s WiFi address for a graphical representation of the 5×7 LED matrix. Pick a color, turn pixels on or off, or choose a predefined pattern and send it to the hardware. This is a powerful way to get use input and with this as a guide it’s fast to set up for pretty much an application you can think of. Just work your way through the documents he put together for the workshop (Zip file link), including all of the code and the slides he used to run the workshop.

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Forget Wifi Or Bluetooth, Pair Directly With Your Phone’s Speaker

October 30, 2016 by 14 Comments

[Kedar Nimbalkar] hyperbolically advertises the ultimate cell phone speaker dock. It costs a dollar. It doesn’t need you to pair with it via Bluetooth or WiFi. It pairs extremely fast, 0.000000000001, he clarifies. It may also look like a broken laptop speaker with a stomped wall wart soldered to it, but who can keep up with industrial design trends these days?

He shows us the device in operation. He starts playing some music on his phone’s speaker. It’s not very loud, so he simply lays the phone on the dock. Suddenly, all the audio fidelity a Dell Lattitude from the 90s can provide erupts from the device! How is this done?

Of course, there’s not much to the trick. Since the cellphone speaker is a coil it can induce a small current in another coil. The resulting voltage can be picked up by an audio amplifier and played through the speakers. Nonetheless it’s pretty cool, and we like his suggestion of betting our friends that we could wirelessly pair with their ear buds. Video after the break.

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Converting A TP Link Router To Mission Control For Cheap 433MHz Home Automation

October 26, 2016 by 11 Comments

[Jean-Christophe Rona] found himself with some free time and decided to finish a project he started two years ago, reverse engineering cheap 433MHz home automation equipment. He hopes to control his space heaters remotely, in preparation for a cold and, now, robotic winter.

In a previous life, he had reverse engineered the protocol these cheap wireless plugs, garage doors, and electric window shutters all use. This eventually resulted in a little library called rf-ctrl that can toggle and read GPIO pins in the correct way to control these objects. He has a few of the more popular protocols built into the library and even wrote a guide on how to do the reverse engineering yourself if you have need.

Having successfully interfaced with the plugs to use with his space heaters, [Jean-Christophe] went about converting a cheap TP Link router into a command center for them. Since TP Link never expected anyone to hammer their square peg into a mismatched hole, it takes a careful hand at soldering and some enamel wire to break out the GPIO pins, but it’s well within the average skill set.

The end result is a nicely contained blue box with a little antenna hanging out of it, and we hope, a warm abode for the coming winter.

Internet Doorbell Gone Full-Hipster

October 24, 2016 by 9 Comments

There are things and there are Things. Hooking up an Internet-connected doorbell that “rings” a piezo buzzer or sends a text message is OK, but it’s not classy. In all of the Internet-of-Things hubbub, too much attention is paid to the “Internet”, which is actually the easy part, and too little attention is paid to the “Things”.

[Moris Metz] is a hacker in Berlin who has a bi-weekly national radio spot. (Only in Germany!) This week, he connected the ubiquitous ESP8266 to a nice old (physical) bell for his broadcast over the weekend. (i”Translated” here.) Check out the video teaser embedded below.

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