Talking Garbage Can Keeps Eye On Playground

September 1, 2018 by Tom Nardi 7 Comments

Getting young kids excited about technology and engineering can be a challenge, and getting them interested in the environment isn’t exactly a walk in the park either. So any project that can get them simultaneously engaged in both is a considerable achievement, especially when they can do the work themselves and see how creating something can have a positive impact on their little corner of the world.

[Robert Hart] writes in to tell us about a project that challenged elementary school students to help make sure their peers put trash in its place. The kids came up with some predictably imaginative ideas like a robot to chase down litterers, but as us grown up hackers know all too well, budget and practicality often end up dictating the project’s final form. In the end, they came up with a talking trash can that gives words of encouragement to passerby.

The heart of the system is an Adafruit Audio FX sound board, which has been loaded up with audio clips recorded by the students. The buttons on the front of the can trigger different messages about why it’s important to make sure trash is disposed of properly, and an internal switch allows the can to thank the user for their deposit when the lid has been opened.

A PIR sensor on the front of the can detects when somebody gets close, and plays a message reminding them to make use of the trash cans provided on the playground. It’s not everyday that a child has a garbage can talk to them, so we think this is a fantastic idea for getting a kid’s attention. In keeping with the ecological friendly theme, the whole system is powered by a small solar panel which charges an internal 3.7V LiPo battery with the help of an Adafruit PowerBoost 500.

We’ve seen plenty of unusual projects here at Hackaday, but even for us, a talking garbage can is something of a rarity. Ironically though, we have seen a garbage can which can follow you around, so maybe the kids weren’t so far off with their original idea after all…

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When Every Last Nanoamp Matters

August 18, 2018 by Brian Benchoff 21 Comments

You can get electricity from just about anything. That old crystal radio kit you built as a kid taught you that, but how about doing something a little more interesting than listening to the local AM station with an earpiece connected to a radiator? That’s what the Electron Bucket is aiming to do. It’s a power harvesting device that grabs electricity from just about anywhere, whether it’s a piece of aluminum foil or a bunch of LEDs.

The basic idea behind the Electron Bucket is to harvest ambient radio waves just like your old crystal radio kit. There’s a voltage doubler, a rectifier, and as a slight twist, a power management circuit that would normally be found in battery-powered electronics.

Of course, this circuit can do more than harvesting electricity from ambient radio waves. By connecting a bunch of LEDs together, it’s possible to send a few Bluetooth packets around. This is pretty impressive — the circuit is using LEDs as solar cells, which normally produce about 50nA of current at 0.5V in direct sunlight. By connecting 12 LEDs in parallel and series, it manages to harvest just enough energy to run a small wireless module. That’s impressive, and an interesting entry to the Power Harvesting Challenge in this year’s Hackaday Prize.

DIY Wind Turbine For Where The Sun Doesn’t Shine

August 14, 2018 by Rich Hawkes 25 Comments

There are plenty of places outside where you may like to have a project requiring electricity that may not get enough sun for solar power to be viable. Perhaps wind power could be used instead? [Greg] has a project to create a platform for using a small wind turbine to generate the power for your projects.

The wind turbine that [Greg] designing is a Savonius-style wind turbine that would put out between 5 and 12 volts. In a Savonius turbine, blades are mounted on a vertical axis allowing for a smaller, less complicated build than traditional horizontal axis wind turbines. The design is named for its inventor, Finnish engineer Sigurd Johannes Savonius.

After doing some research, the design will have a 2:1 height to blade ratio and use three pairs of overlapping curved blades stacked on top of each other, each pair offset by 120 degrees. This design, [Greg] figures, will come within a few percentage points of the efficiency of more exotic blade shapes while making the windmill easy to design and implement. Being half cylinders, the blades can easily be made from existing objects cut in half – pop cans, for example, but there has been some designing the blades in Fusion 360 for 3D printing. The stator board has been designed and the initial prototypes of it and the rotor have arrived, so the testing can now commence.

Once the design is finalized and the prototype working, it’d be interesting to see some projects start showing up using wind power instead of solar power. Take a look at this design for a vertical wind turbine, and this design for a simple, straightforward turbine.

Power Generation Modules Mix And Match Wind, Water, And Hand Cranks

August 13, 2018 by Donald Papp 8 Comments

What’s great about the Power Generation Modules project headed by [Cole B] is the focus on usability and modularity. The project is a system for powering and charging small devices using any number and combination of generator modules: wind turbine, hand-crank, and water turbine so far. Power management and storage is handled by a separate unit that acts as a battery bank to store the output from up to six generators at once. There’s also a separate LED lamp module, designed to be capable of being powered directly from any of the generator modules if needed.

The hand crank is straightforward in concept, but key to usability was selecting a DC gearmotor with a gear ratio that made cranking by hand both comfortable and sustainable; too weak of a crank and it’s awkward, too hard and it’s tiring. The wind turbine has three compact vanes that turn a central shaft, but testing showed the brushless motor it uses as a generator isn’t a good match for the design; the wind turbine won’t turn well in regular wind conditions. The water turbine prototype showed great success; it consists of an epoxy-glazed, 5 inch diameter 3D printed propeller housed in a section of PVC pipe. The propeller drives a brushless motor which [Cole B] says easily outputs between eight to ten volts when testing in a small stream.

The team has plans for other generators such as solar, but this is a great start to an array of modules that can be used to power and charge small devices while off the grid. We’re happy to see them as a finalist for The Hackaday Prize; they were selected as one of the twenty projects to receive $1000 cash each in the Power Harvesting Challenge. The Human-Computer Interface Challenge is currently underway which seeks innovative ideas about how humans and computers can interface with one another, and twenty of those finalists will also receive $1000 each and be in the running for the Grand Prize of $50,000.

Lily Power Pods Make The Seebeck Effect Look Good

August 11, 2018 by Donald Papp 7 Comments

Small proof of concept generating just under one volt in cloudy conditions.

The Seebeck effect (part of the broader thermoelectric effect) is how a difference in temperature can be directly converted into a voltage, and it is the operating principle behind things like thermocouples and Peltier junctions. Harnessing this effect in an effort to wrangle a useful electrical current out of the environment has led to some interesting ideas, like the Lily Power Pods by [Josh Starnes].

What’s interesting about this particular design is that the artistic angle crosses over with functionality. Electrically speaking, the pods have one side of the thermoelectric generator heated by the sun while the other is cooled by being submerged in water, and the temperature differential creates a measurable voltage. [Josh] designed the pods to resemble flowers, with foil petals that help direct sunlight towards the blackened “hot side” of the thermoelectric generator while water takes care of the cool side.

Are foil petals the best way to gather and direct sunlight? They are not, but the idea is to have the pods look like something other than the floating hunks of machinery that they are. Since the pods must float in water and be exposed to sunlight, they will as a result have high visibility. [Josh] seems to feel that it’s important that they not be an eyesore. After all, a less efficient generator that doesn’t overstay its welcome still generates more power than one that has figuratively been handed its hat and told to move along.

PTPM Energy Scavenger Aims For Maintenance-Free Sensor Nodes

August 1, 2018 by Donald Papp 13 Comments

[Mile]’s PTPM Energy Scavenger takes the scavenging idea seriously and is designed to gather not only solar power but also energy from temperature differentials, vibrations, and magnetic induction. The idea is to make wireless sensor nodes that can be self-powered and require minimal maintenance. There’s more to the idea than simply doing away with batteries; if the devices are rugged and don’t need maintenance, they can be installed in locations that would otherwise be impractical or awkward. [Mile] says that goal is to reduce the most costly part of any supply chain: human labor.

The prototype is working well with solar energy and supercapacitors for energy storage, but [Mile] sees potential in harvesting other sources, such as piezoelectric energy by mounting the units to active machinery. With a selectable output voltage, optional battery for longer-term storage, and a reference design complete with enclosure, the PPTM Energy Scavenger aims to provide a robust power solution for wireless sensor platforms.

Flat Pack Generators

July 30, 2018 by Brian Benchoff 11 Comments

We just wrapped up the Power Harvesting challenge in the Hackaday Prize, and with that comes some solutions to getting power in some very remote places. [Vijay]’s project is one of the best, because his project is getting power in Antarctica. This is a difficult environment: you don’t have the sun for a significant part of the year, it’s cold, and you need to actually get your equipment down to the continent. [Vijay]’s solution was to use one of Antarctica’s greatest resources — wind — in an ingenious flat pack wind turbine.

There are a few problems to harvesting wind power in a barren environment. The first idea was to take a standard, off-the-shelf motor and attach some blades, but [Vijay] found there was too much detent torque, and the motor would be too big anyway.

The solution to this problem was to wind his own motor that didn’t have the problems of off-the-shelf brushless motors. The design that [Vijay] settled on is a dual axial flux generator, or a motor with a fixed stator with magnets and two rotors loaded up with copper windings. Think of it as a flattened, inverted version of the motor on your drone.

One interesting aspect of this design is that it takes up significantly less space than a traditional motor, while still being able to output about 100 Watts with the wind blowing. Add in some gearing to get the speed of the rotor right, and you have a simple wind generator that can be set up in minutes and carried anywhere. It’s a great project, and we’re glad to see this make it into the finals of The Hackaday Prize.