Solar power is a great source of renewable energy, but has always had its limitations. At best, there’s only 1,000 Watts/m2 available at the Earth’s surface on a sunny day, and the limited efficiency of solar panels cuts this down further. It’s such a low amount that solar panels on passenger cars have been limited to menial tasks such as battery tending and running low-power ventilation fans.
However, where some might see an impossibility, others see opportunity. The World Solar Challenge is a competition that has aimed to show the true potential of solar powered transport. Now 30 years since its inception, what used to be impossible is in fact achieved by multiple teams in under one tenth of the original time. To keep competitors on their toes, the rules have been evolving over time, always pushing the boundaries of what’s possible simply with sunlight. This isn’t mainstream transportation; this is an engineering challenge. How far can you go in a solar car?
At one end of the synthesizer world, there stands commercial instruments designed for the ultimate in sound quality and performance, tailored to the needs of professional musicians. On the other, there are weird, wacky prototypes and artistic builds that aim to challenge our conception of what a synth should be. The VOC-25 by [Love Hultén] falls firmly in the latter category.
The synth is built around the Axoloti Core, a microcontroller board set up for audio experimentation. Packing stereo DACs and ADCs, and MIDI input and output, it’s the perfect base for such a project. Loaded up with vocal samples, it’s played by a keyboard in a fairly typical sense. Where things get interesting is the panel containing 25 sets of plastic teeth. The teeth open and close when the user plays the corresponding note, thanks to a solenoid. Along with the clacking sound of the machinery and pearly whites themselves, it adds quite a creepy vibe to the piece.
With its clean pastel enclosure, we can imagine this piece as the star of an avant-garde filmclip, or merely something to terrify children at a Maker Faire. It’s a fun build, to be sure. We’ve seen some other great experimental synths over the years, too – this 48 Game Boy build comes to mind. Video after the break.
Smartphones are portals to an overwhelming torrent of information. Yes, they’re a great way to find out the time, your bus schedule, and the weather, but they’re also full of buzzers and bells going off every three minutes to remind you that your uncle has reposted a photo of the fish he caught ten years ago. Sometimes, it’s better to display just the essentials, and that’s what Weather Note does.
It’s built around the Adafruit Feather Huzzah, a devboard built around the venerable ESP8266. It’s a great base for an Internet of Things project like this one, with WiFi built-in and ready to go. The Weather Note talks to a variety of online platforms to scrape weather data and helpful reminders, with the assistance of If This Then That, or IFTTT. Reminders to walk the dog or get some milk are displayed on a small OLED screen, while there’s also a bunch of alphanumeric displays for other information. WS2812 LEDs are used behind a shadowbox to display weather conditions, with cute cloud, rain, and sun icons. It’s all wrapped up in a tidy frame perfect for the mantlepiece or breakfast table.
It’s a great build to learn about programming for the Internet of Things, and with those bright LED displays, it’s probably a viable nightlight too. It’s a rare project that can both tell you about the weather and keep you from stubbing your toe in the kitchen, after all. Those desiring a stealthier build should consider going down the smart mirror route instead. Video after the break.
It’s a job that’s ideally suited for the average microcontroller. In this case, [Alex] chose the venerable Arduino Uno. Paired with a bunch of buttons and a 16 x 2 character LCD, it has a simple-to-navigate interface for dialling in a shot. The trick to splash and droplet photography is to first open a valve to release a droplet, and then fire a flash a set time after to capture the droplet in flight, after it’s hit the surface of the liquid. [Alex]’s design uses a MOSFET to trigger the water valve, and optoisolators to safely trigger the flash and camera.
[Alex] has gotten some impressive results with the rig, and it would serve as a great starting point for anyone looking to get into the field. We’ve seen similar builds before, too. If you’ve got your own fancy photography rig for those otherwise-impossible shots, be sure to drop us a line!
Humans often like to monitor their exercise habits with the use of a pedometer, which tracks steps taken during a walk. Such devices are a little cumbersome for smaller creatures however, but no matter. Hamsters tend to get most of their workouts done on a wheel anyway, so it’s simple enough to instrument the equipment instead.
The build is a simple tachometer, using an infrared emitter and sensor pair to read the rotation speed of the hamster wheel. The wheel itself is light-colored plastic, so a strip of black felt is used to create a non-reflective section, creating a pulse one per revolution that can be read by the Adafruit Feather 32U4 running the show. Data on peak speed and total rotations is available for tracking the exercise habits of the hamster in question, output on a set of 14-segment displays.
It’s a fun project, and one that would be a great way to teach kids about pet care and basic embedded systems. Hamster performance could even be uploaded to the cloud with a more advanced build, and training milestones linked to rewards a la Premier League footballers. At the end of the day, a hamster wheel is just an exercise bike for our four-legged friends, and we’ve seen those hacked too. Video after the break.
Growing fresh vegetables at home is a popular pastime, even moreso in a year when we’ve all been locked inside. However pests can easily spoil a harvest, potentially putting a lot of hard work down the drain. [Matt] of [DIY Perks] isn’t one to give up his tomatoes without a fight, however, and came up with a solution to protect his plants.
The trick is to take advantage of the mildly conductive slime excreted by snails as they travel along the ground. To protect potted plants, [Matt] places two strips of copper tape around the perimeter of the pot, spaced about a centimeter apart. Each strip is connected to one terminal of a 9 V battery. When a snail attempts to cross the strips, it completes a circuit between the two, and the electrical current that flows irritates the snail, forcing it to retreat.
[Matt] notes that no snails were harmed in the making of the video, and that the solution is far kinder to the slimy critters than poisons or traps. He also goes so far as to demonstrate alternative solutions for garden beds, as well. We’ve more commonly seen [Matt] working with lighting, though it’s great to see he has a bit of a green thumb, too. Video after the break.
These days, we’re blessed with cellular data networks that span great swathes of the Earth. By and large, they’re used to watch TV shows and argue with strangers online. However, they’re also a great tool to use to interact with hardware in remote locations, particularly mobile ones where a wired connection is impractical.
In this series, we’re taking a look at tips and tricks for doing remote cellular admin the right way. First things first, you’ll need a data connection – so let’s look at choosing a modem.
Options Abound
When shopping around for cellular data modems, it can be difficult to wade through the variety of options out there and find something fit for purpose. Modems in this space are often marketed for very specific use cases; at the consumer level, many are designed to be a no-fuss home broadband solution, while in the commercial space, they’re aimed primarily to provide free WiFi for restaurants and cafes. For use in remote admin, the presence of certain features can be critical, so it pays to do your research before spending your hard earned money. We’ve laid out some of the common options below.
Consumer Models
The Sierra Aircard 320U is ancient now, with limited frequency bands available. Its flimsy flexible connector is also a drawback. However, its ease of configuration with Linux systems makes it a dream to use in remote access situations. Unlike many others, it acts as a Direct IP connection, not appearing as a separate router.
Many telecommunications providers around the world sell cheap USB dongles for connecting to the Internet, with these first becoming popular with the rise of 3G. They’re somewhat less common now in the 5G era, with the market shifting more towards WiFi-enabled devices that share internet among several users. These devices can often be had for under $50, and used on prepaid and contract data plans.
These devices are often the first stop for the budding enthusiast building a project that needs remote admin over the cellular network. However, they come with certain caveats that can make them less attractive for this use. Aimed at home users, they are often heavily locked down with firmware that provides minimal configuration options. They’re generally unable to be set up for port forwarding, even if you can convince your telco to give you a real IP instead of carrier-grade NAT. Worse, many appear to the host computer as a router themselves, adding another layer of NAT that can further complicate things. Perhaps most frustratingly, with these telco-delivered modems, the model number printed on the box is often not a great guide as to what you’re getting.
A perfect example is the Huawei E8327. This comes in a huge number of sub-models, with various versions of the modem operating in different routing modes, on different bands, and some even omitting major features like external antenna connectors. Often, it’s impossible to know exactly what features the device has until you open the box and strip the cover off, at which point you’re unable to return the device for your money back.
All is not lost, however. The use of VPNs can help get around NAT issues, and for the more adventurous, some models even have custom firmware available on the deeper, darker forums on the web. For the truly cash strapped, they’re a viable option for those willing to deal with the inevitable headaches. There are generally some modems that stand out over others in this space for configurability and ease of use. This writer has had great success with a now-aging Sierra Aircard 320U, while others have found luck with the Huawei E3372-607. As per earlier warnings though, you don’t want to accidentally end up with an E3372-608 – thar be dragons.
