A research group at the University of Rochester has developed a new polymer with some amazing traits. It can be stretched or manipulated into new shapes, and it will hold that shape until heat is applied. Shape-shifting polymers like this already exist, but this one is special: it can go back to its original shape when triggered by the heat of a human body. Oh, and it can also lift objects up to 1000 times its mass.
The group’s leader, chemical engineering professor [Mitch Anthamatten], is excited by the possibilities of this creation. When the material is stretched, strain is induced which deforms the chains and triggers crystallization. This crystallization is what makes it retain the new shape. Once heat is applied, the crystals are broken and the polymer returns to its original shape. These properties imply several biomedical applications like sutures and artificial skin. It could also be used for tailored-fit clothing or wearable technology.
The shape-shifting process creates elastic energy in the polymer, which means that it can do work while it springs back to normal. Careful application of molecular linkers made it possible for the group to dial in the so-called melting point at which the crystallization begins to break down. [Anthamatten] explains the special attributes of the material in one of the videos after the break. Another video shows examples of some of the work-related applications for the polymer—a stretched out strand can pull a toy truck up an incline or crush a dried seed pod.
Electric cars are all the rage lately, but let’s not forget about the old standby – internal combustion. The modern internal combustion engine is a marvel of engineering. Today’s engines and surrounding systems have better power, greater fuel economy, and lower emissions than anything that has come before. Centuries’ worth of engineering hours have gone into improving every aspect of the engine – with one notable exception. No automotive manufacturer has been able to eliminate the engine’s camshaft in a piston powered-production vehicle. The irony here is that camless engines are relatively easy to build. The average hacker could modify a small four-stroke engine for camless operation in their workshop. While it wouldn’t be a practical device, it would be a great test bed for experimentation and learning.
Suck, Squeeze, Bang, Blow
A multi-cylinder gasoline engine is a complex dance. Hundreds of parts must move in synchronicity. Valves open and close, injectors mist fuel, spark plugs fire, and pistons move up and down. All follow the four-stroke “Intake, Compression, Combustion, Exhaust” Otto cycle. The camshaft controls much of this by opening and closing the engine’s spring-loaded intake and exhaust valves. Lobes on the shaft press on tappets which then move the valve stems and the valves themselves. The camshaft itself is driven at half the speed of the crankshaft through timing gears, chains, or a belt. Some valve trains are relatively simple – such as overhead cam engines. Others, such as the cam-in-block design, are more complex, with pushrods, rockers, and other parts required to translate the movement of the cam lobe to movement at the valve.
Exactly when, and how fast a valve opens is determined by the profile of the cam lobe. Auto racing and performance enthusiasts often change camshafts to those with more aggressive profiles and different timing offsets depending on the engine’s requirements. Everything comes at a cost though. A camshaft machined for maximum power generally won’t idle well and will make the engine harder to start. Too aggressive a lobe profile can lead to valve float, where the valves never fully seat at high RPM.
Myriad Solutions
Engine manufacturers have spent years working around the limitations of the camshaft. The results are myriad proprietary solutions. Honda has VTEC, short for Variable Valve Timing and Lift Electronic Control. Toyota has VVT-i. BMW has VANOS, Ford has VCT. All these systems provide ways to adjust the valve action to some degree. VANOS works by allowing the camshaft to slightly rotate a few degrees relative to its normal timing, similar to moving a tooth or two on the timing chain. While these systems do work, they tend to be mechanically complex, and expensive to repair.
The simple solution would be to go with a camless engine. This would mean eliminating the camshaft, timing belt, and most of the associated hardware. Solenoids or hydraulic actuators open and close the valves in an infinitely variable number of ways. Valves can even be held open indefinitely, effectively shutting down a cylinder when max power isn’t necessary.
So why aren’t we all driving camless engines? There are a few reasons. The advantages of camless engines to camshaft engines are analogous to the advantages of electronic fuel injection (EFI) vs carburetors. At the core, a fuel injector is a solenoid controlled valve. The fuel pump provides constant pressure. The engine control unit (ECU) fires the injectors at just the right time to inject fuel into the cylinders.The computer also leaves the valves open long enough so that the right amount of fuel is injected for the current throttle position. Electronically this is very similar to what would be required for a camless engine. So what gives?
Toyota’s celebrated 22R-E, an early EFI engine
Hackers in their 30’s and beyond will remember that until the late 1970’s and early 1980’s, the carburetor was king. Companies had been experimenting with EFI since the 1950’s. The system didn’t become mainstream until the stiff pollution laws of the 70’s came into effect. Making a clean, fuel-efficient carbureted engine was possible, but there were so many mechanical and electronic actuators required that the EFI was a better alternative. So the laws of the 70’s effectively regulated carburetors out of existence. We’re looking at much the same thing with camless engines. What’s missing are the regulations to force the issue.
All the big manufacturers have experimented with the camless concept. The best effort to date has been from Freevalve, a subsidiary of Koenigsegg. They have a prototype engine running in a Saab. LaunchPoint Technologies have uploaded videos showing some impressive actuator designs LaunchPoint is working with voice coils, the same technology which moves the heads in your hard drive.
None of this means that you can’t have a camless engine now – companies like Wärtsilä and Man have engines commercially available. However, these are giant diesel engines used to drive large ships or generate power. Not exactly what you’d want to put in a your subcompact car! For the hacker set, the best way to get your hands on a camless engine today is to hack one yourself.
Ladies and gentlemen, start hack your engines!
Simple, single-cylinder camless engines are relatively easy to build. Start with a four stroke overhead valve engine from a snowblower, scooter, or the like. Make sure the engine is a non-interference model. This means that it is physically impossible for the valves to crash into the pistons. Add a power source and some solenoids. From there it’s just a matter of creating a control system. Examples are all over the internet. [Sukhjit Singh Banga] built this engine as part of a college project. The control system is a mechanical wheel with electric contacts, similar to a distributor cap and rotor system. [bbaldwin1987’s] Camless Engine Capstone project at West Virginia University uses a microcontroller to operate the solenoids. Note that this project uses two solenoids – one to open and one to close the valve. The engine doesn’t need to rely on a spring for closure. [Brian Miller] also built a camless engine for college, in this case Brigham Young University Idaho Camless Engine. [Brian’s] engine uses hall effect sensors on the original camshaft to fire the solenoids. This route is an excellent stepping stone before making the jump to full electronic control.
It wouldn’t take much work to expand these projects to a multi-cylinder engine. All we’re waiting for is the right hacker to take up the challenge!
When a hacker finds himself with a metal disc and magnet surgically implanted in his skull, chances are pretty good that something interesting will come from it. [Eric Cherry]’s implant, designed to anchor a bone-conduction hear aid, turned out to be a great place to mount a low-cost Bluetooth speaker for his phone – at least when he’s not storing paperclips behind his ear.
With single-sided deafness, [Eric]’s implant allows him to attach his bone-anchored hearing aid (BAHA), which actually uses the skull itself as a resonator to bypass the outer ear canal and the bones of the middle ear and send vibrations directly to the cochlea. As you can imagine, a BAHA device is a pretty pricey bit of gear, and being held on by just a magnet can be tense in some situations. [Eric] decided to hack a tiny Bluetooth speaker to attach to his implant and see if it would work with his phone. A quick teardown and replacement of the stock speaker with a bone-conduction transducer from Adafruit took care of the electronics, which were installed in a 3D printed enclosure compatible with the implant. After pairing with his phone he found that sound quality was more than good enough to enjoy music without risking his implant. And all for only $22 out-of-pocket. While only a Bluetooth speaker in its current form, we can see how the microphone in the speakerphone might be used to build a complete hearing aid on the cheap.
We think this is a great hack that really opens up some possibilities for the hearing impaired. Of course it’s not suitable for all types of hearing loss; for more traditional hearing aid users, this Bluetooth-enabled adapter might be a better choice for listening to music.
Computer Numeric Control technology has been around for a long time. It’s at the heart of our 3D printers, laser cutters / etchers and CNC milling machines. They all work the same way — you begin with a CAD program and make some type of design. Then the computer converts the file into a set of XYZ coordinates and moves a tool head accordingly. Now let us pose to ourselves a most interesting question. What if you reversed the process? What if you could take a CNC’d object and convert it into XYZ coordinates?
This is precisely what [dave] is attempting to do. He’s made a basic CNC outfit and installed encoders on the steppers. He then manually moves the tool head to trace out an object. At the same time, the encoders are feeding the coordinates to a computer for recording. The idea is to replay the coordinates to see if the CNC can replicate the object.
Judging from the video below, the project is a success!
Throwing a 5V regulator like the LM7805 at our projects can become habit forming, after all they’re dirt cheap and the circuit is about as basic as they come with only two external components, an input and output cap. As this is a good enough solution to most of our 5V circuits we can come into some issues if we aren’t paying attention. Linear regulators can only dissipate so much power in the form of heat before they need a heat sink and/or active cooling. Even if they can produce a cleaner output, in an embedded system, large power losses to heat are less than ideal to say the least.
[Daniel] needed an efficient solution to use in the place of an LM7805, after looking at the drop-in replacement switching solutions available on Adafruit’s website, he headed to DigiKey for a similar and less expensive part. [Daniel] collected some data and found the regulator to be 92% efficient with a 12V input, which is not quite the claimed 97% but a good solution nonetheless.
For a lot of us some sort of audio circuit was our first endeavor into electronics. Speak and Spell, atari punk console, LM386 in a mint tin, sound familiar? If not, you should do yourself a favor and knock out a couple of those simple projects. For those of us who have done a bit of what the kids are calling circuit bending, [Nickolas Peter] brings us a familiar hack with his Patient Alpha project. You can see a time-lapse video of the build process and a short demo in the video after the break.
[Nickolas] did a few mods to his 2013 Executor key fob; the obligatory potentiometer for resistor swap is always a crowd pleaser. Adding an audio out via 3.5 mm jack is something that some of us wouldn’t have thought to include, but it lets the Executor scream into your serious audio gear for maximum eargasms. It’s worth mentioning that [Nickolas] does a good job with this hack’s finished look, albeit he started with a product in an enclosure he still goes to the trouble of custom fitting all his bits in an aesthetically pleasing way. And then he made a second.
What happens when you give a former Navy weapons engineer some development boards and ask him to build “something cool”? What happens when you give a kid finger paints? [Seb] obviously built an IoT Nerf Turret Gun controlled via a team communication app.
The weapon was a Nerf Stampede which was hacked so it could be fired electronically. The safety switch was bypassed and a relay provided the firing signal. The electronics stack consists of an Intel Galileo, a motor shield and a relay shield. The turret assembly was built using off the shelf structural parts from Actobotics. Stepper motors provide motion to the turret. The fun begins with how the software is implemented. An iBeacon network detects where people sit at in the office. So when you type in the name of your target in a messaging app, it knows where they’re sitting, aims at them, and pops a nerf dart at them.
The lessons learned are what makes such projects worth their while. For example, USB is a standard. And the standard says that USB cables be not more than 1.8 m long. [Seb] was reminded of this when his electronics worked on his workbench, but refused to work when placed in-situ and connected via a 3m long cable – the serial link just wouldn’t work.
Mounting the gun such that it was nicely balanced was another challenge. Eventually, he had to use a couple of AA cells taped to the front of the gun to get it right. This could be useful though, since he plans to replace the dead weights with a sighting camera. One last hack was to zip tie heat sinks to the motor drivers, and he had a good reason to do that. Read more about it in his blog. And check out the video as someone takes aim and shoots a target via SLACK, the team messaging application.
A multi-cylinder gasoline engine is a complex dance. Hundreds of parts must move in synchronicity. Valves open and close, injectors mist fuel, spark plugs fire, and pistons move up and down. All follow the four-stroke “Intake, Compression, Combustion, Exhaust” 
Engine manufacturers have spent years working around the limitations of the camshaft. The results are myriad proprietary solutions. Honda has VTEC, short for Variable Valve Timing and Lift Electronic Control. Toyota has VVT-i. BMW has VANOS, Ford has VCT. All these systems provide ways to adjust the valve action to some degree. VANOS works by allowing the camshaft to slightly rotate a few degrees relative to its normal timing, similar to moving a tooth or two on the timing chain. While these systems do work, they tend to be mechanically complex, and expensive to repair.
Simple, single-cylinder camless engines are relatively easy to build. Start with a four stroke overhead valve engine from a snowblower, scooter, or the like. Make sure the engine is a non-interference model. This means that it is physically impossible for the valves to crash into the pistons. Add a power source and some solenoids. From there it’s just a matter of creating a control system. Examples are all over the internet. [Sukhjit Singh Banga] built 
