Emulating A Remote Control Ceiling Fan Transmitter In An FPGA

[Joel] has a remote control ceiling fan. It’s nothing special, the controller has a low-power 350MHz transmitter and a Holtek encoder to send commands by keying the transmitter’s output. Desiring something a little better, he set about reverse engineering the device’s protocol and implementing it on a Lattice iCE40 FPGA.

To decode the device’s packets he reached for his RTL-SDR receiver and took a look at it in software. GQRX confirmed the presence of the carrier and allowed him to record a raw I/Q file, which he could then supply to Inspectrum to analyse the packet structure. He found it to be a simple on-off keying scheme, with bits expressed through differing pulse widths. He was then able to create a Gnu Radio project to read and decode them in real time.

Emulating the transmitter was then a fairly straightforward process of generating a 350MHz clock using the on-board PLL and gating it with his generated data stream to provide modulation. The result was able to control his fan with a short wire antenna, indeed he was worried that it might also be doing so for other similar fans in his apartment complex. You can take a look at his source code on GitHub if you would like to try something similar.

It’s worth pointing out that a transmitter like this will radiate a significant amount of harmonics at multiples of its base frequency, and thus without a filter on its output is likely to cause interference. It will also be breaking all the rules set out by whoever the spectrum regulator is where you live, despite its low power. However it’s an interesting project to read, with its reverse engineering and slightly novel use of an FPGA.

Wireless remote hacking seems to be a favorite pastime here in the Hackaday community. We’ve had 2.4GHz hacks and plenty of wireless mains outlet hacks.

Hackaday Prize Entry: DIY Foot Orthotics

What does your gait look like to your foot? During which part of your gait is the ball of your feet experiencing the most pressure? Is there something wrong with it? Can you fix it by adding or removing material from a custom insole? All these answers can be had with an expensive system and a visit to a podiatrist, but if [Charles Fried] succeeds you can build a similar system at home. 

The device works by having an array of pressure sensors on a flat insole inside of a shoe. When the patient walks, the device streams the data to a computer which logs it. The computer then produces a heat map of the person’s step. The computer also produces a very useful visualization called a gait line. This enables the orthotist to specify or make the correct orthotic.

[Charles]’s version of this has another advantage over the professional versions. His will be able to stream wirelessly to a data logger. This means you can wear the sensor around for a while and get a much more realistic picture of your gait. Like flossing right before the dentist, many people consciously think about their gait while at the foot doctor; this affects the result.

He currently has a prototype working. He’s not sure how long his pressure sensors will last in the current construction, and he’s put wireless logging on hold for now. However, the project is interesting and we can’t wait to see if [Charles] can meet all his design goals.

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Shipwreck Exploration Vessels Fit in Minivan; Stream to Internet

Having to work away from the convenience of a workshop can be tough. But it’s sometimes unavoidable and it always means planning ahead. When the work area also happens to be 150m under a lake’s surface, it’s much more of a challenge – but it’s both doable and more accessible than you might think. To prove it, this DIY research vessel will be part of the robotic exploration of an underwater shipwreck. It is complete with an Ethernet bridge, long-range wireless communications, remotely operated underwater vehicle (ROV), the ability to hold a position, and more. The best part? It can all be packed up and fit into a minivan. We can’t put it any better than the folks at the OpenROV Forums:

In just over a week (June 6th – 9th), a bunch of people from OpenROV are going to attempt to dive a set of specially modified deep-capable ROVs to a 50m-long shipwreck at a depth of 150m below lake Tahoe. We’ll be using a deployment architecture that we’ve been perfecting over the years that involves a very small boat keeping station over the dive site while the rest of the people on the expedition run the mission from a remote location via long-range broadband radio. Since the mission control site will have an internet connection, we’ll be able to live stream the entire dive over the internet.

OpenROV DIY Research VesselThe purpose of the design was “to demonstrate that many of the capabilities one might think would require a large research vessel can actually be achieved with off-the-shelf parts that are more portable and much less expensive. […] There’s a lot to discover down there, and the technology readily available these days can allow us to explore it.” This mindset happens to wonderfully complement the kickoff of the Citizen Scientist Challenge portion of the 2016 Hackaday Prize.

For those times when your work can remain on solid ground, one method is to sidestep the entire issue of working away from the workshop by simply making your whole work area mobile like this incredible conversion of a truck trailer to a mobile lab.

Coolest, but Least Secure, Security Device

[Matikas] apparently forgets to lock the screen on his computer when he gets up to grab a coffee. And he apparently works with a bunch of sharks: “If you don’t [lock it], one of your colleagues will send email to the whole company that you invite them to get some beer (on your bill, of course).” Not saying we haven’t done similar, mind you. Anyway, forgetting to lock your screen in an office environment is serious business.

So [Matikas] built a great system that remotely types the keystrokes to lock his screen, or unlock it with his password. An off-the-shelf 433 MHz keyfob is connected to an Arduino micro that simulates a keyboard attached to his computer. It’s a simple system, but it’s a great effect. (See the video demo, below.)

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BeagleBone Green, Now Wireless

Over the past few years, the BeagleBone ecosystem has grown from the original BeagleBone White, followed two years later by the BeagleBone Black. The Black was the killer board of the BeagleBone family, and for a time wasn’t available anywhere at any price. TI has been kind to the SoC used in the BeagleBone, leading to last year’s release of the BeagleBone Green, The robotics-focused BeagleBone Blue, and the very recent announcement of a BeagleBone on a chip. All these boards have about the same capabilities, targeted towards different use cases; the BeagleBone on a Chip is a single module that can be dropped into an Eagle schematic. The BeagleBone Green is meant to be the low-cost that plays nicely with Seeed Studio’s Grove connectors. They’re all variations on a theme, and until now, wireless hasn’t been a built-in option.

This weekend at Maker Faire, Seeed Studio is showing off their latest edition of the BeagleBone Green. It’s the BeagleBone Green Wireless, and includes 802.11 b/g/n, and Bluetooth 4.1 LE.

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Hackaday Prize Entry: Wirelessly Charged Self-Heating Coffee Mug

Many productive hackers bleed a dark ochre. The prevailing theory among a certain group of commenters is that they’re full of it, but it’s actually a healthy sign of a low blood content in the healthy hacker’s coffee stream. [Bharath] is among those who enjoy the caffeinated bean juice on a daily basis. However, he’d suffer from a terrible condition known as cold coffee. To combat this, he built an app-enabled, wirelessly chargeable, self-heating coffee mug.

We know that most hackers don’t start off planning to build objects with ridiculous feature lists, it just happens. Is there an alternate Murphy’s law for this? Any feature that can be added will? The project started off as some low ohm resistors attached to a rechargeable power bank. A insulated flask with a removable inner stainless steel lining was chosen. The resistors were fixed to the outside with a thermal epoxy.

However, how do we control the resistors? We don’t want to burn through our battery right away (which could end up more literally than one would like), so [Bharath] added a Linkit One microcontroller from Seeed Studio. With all this power at his disposal, it was natural to add Bluetooth, a temperature sensor, and app control to the cup.

After getting it all together, he realized that while the insides were perfectly isolated from the liquids held in the flask under normal use, the hole he’d have to cut to connect to the charging circuit would provide an unacceptable ingress point for water. To combat this he added the wireless charging functionality.

With his flask in hand, we’re sure the mood boost from not having to slog through the dregs of a cold container of coffee will produce a measureable improvement in productivity. Video after the break.

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Thinking of You: IoT Style

Do you have loved ones who live far away? Or do you just want an interesting starter ESP8266 project to get your feet wet? If the answer to either of these questions is “yes”, we’ve got just the project for you. [Craig Lindley] built a “thinking of you” button-and-LED display device that helps people keep in touch, in a very simple way.

We like the minimalism of the design. One party presses their button, electrons flow, WiFis WiFi, data travels through a set of tubes, and an LED far away glows a pre-arranged color. The other side can signal back to say “hi” as well. It’s a cute item to have on your desk, or wherever you spend the most time. If you’re new to all of this, you can hardly beat the circuit for its simplicity.

Yeah, you could totally just send the other person a text message or an e-mail. But then you don’t get an excuse to play around with NodeMCU, and it just lacks the personal hacker touch. The code is available in a zip file here, and if you want to stay in touch with someone other than [Craig]’s sisters, you’ll probably want to customize it a bit.