Smart Attic Fan

January 15, 2009 by 5 Comments

fan

[Andrew] lives in Hawaii where the climate usually doesn’t necessitate heating and cooling systems. Usually, some open windows and doors will cool the house down enough. This relies on the breeze though, and that isn’t always there. [Andrew] came up with the solution of automating an attic fan to circulate air depending on outside temperature. Sure, he could have just installed a fan with a switch, but he wanted it to do all the work itself. He used a PIC16F877 as the brains and made the pretty control panel shown above.

Lattice Drops EULA Clause Forbidding FPGA Bitstream Reverse Engineering

June 6, 2020 by 33 Comments

Yesterday we reported that Lattice Semiconductor had inserted a clause that restricted the reverse engineering of bitstreams produced by their FPGA toolchains. Although not explicitly stated, it’s assumed that this was directed toward several projects over the past five years that have created fully open source toolchains by reverse engineering the bitstream protocols of the Lattice ICE40 and ECP5 FPGA architectures. Late yesterday Lattice made an announcement reversing course.

To the open source community, thank-you for pointing out a new bitstream usage restriction in the Lattice Propel license. We are excited about the community’s engagement with Lattice devices and our intent is to not hinder the creation of innovative open source FPGA tools.

It’s refreshing then to see this announcement from Lattice Semiconductor. Even more so is the unexpected turn of speed with which they have done so, within a couple of days of it being discovered by the open-source community. We report depressingly often on boneheaded legal moves from corporations intent on curbing open source uses of their products. This announcement from Lattice removes what was an admonition opposing open source toolchains, can we hope that the company will continue yesterday’s gesture and build a more lasting relationship with the open source community?

The underlying point to this story is that in the world of electronics there has long been an understanding that hardware hackers drive product innovation which will later lead to more sales. Texas Instruments would for years supply samples of exotic semiconductors to impecunious students for one example, and maybe you have a base-model Rigol oscilloscope with a tacitly-approved software hack that gives it an extra 50MHz of bandwidth for another.

We can only congratulate Lattice on their recognition that open source use of their products is beneficial for them, and wish that some of the other companies triggering similar stories would see the world in the same way. Try interacting more with your open source fans; they know and love your hardware more than the average user and embracing that could mean a windfall for you down the road.

Emulating A Remote Control Ceiling Fan Transmitter In An FPGA

July 4, 2016 by 7 Comments

[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.

Boeing’s New Microlattice, Now The Lightest “Metal” Ever

October 23, 2015 by 55 Comments
Mr McGuire: I just want to say one word to you. Just one word.
Benjamin: Yes, sir.
Mr McGuire: Are you listening?
Benjamin: Yes, I am.
Mr McGuire: Plastics.

You may recognize the above dialog from the movie “The Graduate” starring a young [Dustin Hoffman], whose character is getting advice about what line of work he should get into after university. Maybe Mr McGuire’s advice should have been “Microlattice.”

If you take a step back for a moment and survey the state of materials, you’ll see that not much has changed in the last 50 years. We’re still building homes out of dead trees, and most cars are still made out of iron(although that is starting to change.) It’s only been just recently has there been advances in batteries technology – and that only came about with the force of a trillion-dollar mobile phone industry behind it. So we’re excited by any new advance we see, and Boeing’s new “Microlattice” tickles our fancy.

Boeing isn’t giving away the recipe just yet, but here is what we know: it’s 99.99% empty space, making it extremely light. It’s so light, that if you drop it, it floats to the ground. It’s also compressible, giving it the ability to absorb energy and spring back (you can see it in action in the after the break.) It’s made by creating a sacrificial skeletal structure the shape of the final lattice, then coating that template with nickel-phosphorus alloy. The temporary inner structure is then etched away, leaving a “microlattice” of tiny interconnected hollow rods with wall thickness of about 100 nanometers. Of course it doesn’t take a rocket surgeon to figure out why Boeing is interested in such materials, they are eye it as an extremely lightweight building material for planes and spacecraft.

Continue reading “Boeing’s New Microlattice, Now The Lightest “Metal” Ever” →

Building A Passive 3D Projection System In Your Attic

September 13, 2012 by 16 Comments

While the whole 3d movie/game craze seems to be ramping up, it really isn’t a new thing. We all recall those fancy red-blue glasses that were popular in theaters for a while, but I’m not talking about that. Passive 3d projection (using polarized glasses) has been around for a while too. Many people have figured out cheap ways to build these systems in their homes, but only recently have we seen media created for them in quantity.  Now that you can buy 3D games and movies at your local box store, the temptation to have a 3d system in your home is much higher.

Here’s a great read on how to put together a fairly simple projection system that uses two identical projectors with polarizing filters. Basically, all you need are two projectors, two filters, a screen, and the glasses. There are plenty of tips for mounting and setup in the thread to help alleviate any headaches you might encounter.

This system is primarily used with a PC, because it requires two video feeds to function. A cost breakdown might make you wonder why you wouldn’t just jump on amazon and get a 32″ 3d tv for under $400, but sitting in front of that giant screen might make you understand.

1wire Attic Cooling

July 31, 2009 by 28 Comments

blower

[RagingComputer] built this 1-wire attic cooling fan. He’s using an Ubuntu server loaded with OWFS to control everything. The 1-wire temperature sensor is interfaced using USB while a serial x10 module sends out commands to be received by another x10 module near the fan. Back in the day we had covered a linux home automation project. We also covered HVAC hacks such as the smart attic fan and a 1-Wire HVAC monitoring system.