drone

372 Articles

Hyperspectral Imaging – Seeing The Unseeable

October 25, 2017 by 25 Comments

They say that a picture is worth a thousand words. But what is a picture exactly? One definition would be a perfect reflection of what we see, like one taken with a basic camera. Our view of the natural world is constrained to a bandwidth of 400 to 700 nanometers within the electromagnetic spectrum, so our cameras produce images within this same bandwidth.

Image via Cosmos Magazine.

For example, if I take a picture of a yellow flower with my phone, the image will look just about how I saw it with my own eyes. But what if we could see the flower from a different part of the electromagnetic spectrum? What if we could see less than 400 nm or greater than 700 nm? A bee, like many other insects, can see in the ultraviolet part of the spectrum which occupies the area below 400 nm. This “yellow” flower looks drastically different to us versus a bee.

In this article, we’re going to explore how images can be produced to show spectral information outside of our limited visual capacity, and take a look at the multi-spectral cameras used to make them.  We’ll find that while it may be true that an image is worth a thousand words, it is also true that an image taken with a hyperspectral camera can be worth hundreds of thousands, if not millions, of useful data points. Continue reading “Hyperspectral Imaging – Seeing The Unseeable” →

Lithium Ion Versus LiPoly In An Aeronautical Context

October 23, 2017 by 32 Comments

When it comes to lithium batteries, you basically have two types. LiPoly batteries usually come in pouches wrapped in heat shrink, whereas lithium ion cells are best represented by the ubiquitous cylindrical 18650 cells. Are there exceptions? Yes. Is that nomenclature technically correct? No, LiPoly cells are technically, ‘lithium ion polymer cells’, but we’ll just ignore the ‘ion’ in that name for now.

Lithium ion cells are found in millions of ground-based modes of transportation, and LiPoly cells are the standard for drones and RC aircraft. [Tom Stanton] wondered why that was, so he decided to test the energy density per mass of these battery chemistries, and what he found was very interesting.

The goal of [Tom]’s experiment was to test LiPoly against lithium ion batteries in the context of a remote-controlled aircraft. Since weight is what determines flight time, cutting even a few grams from an airframe can vastly extend the capabilities of an aircraft. The test articles for this experiment come in the form of a standard 1800 mAh LiPoly battery and four 18650 cells wired together as a 3000 mAh battery. Here’s where things get interesting: the LiPoly battery weighs 216 grams for an energy density of 0.14 Watt-hours per gram. The lithium ion battery weighs 202 grams for an energy density of 0.25 Watt-hours per gram. If you just look at the math, all drones are doing it wrong. 18650 cells appear to have a much higher energy density per mass than the usual LiPoly cells. How does that hold up in a real-world test, though?

Using his neat plane with 3D printed wing ribs as the testbed, [Tom] plugged in the batteries and flew around a field for the better part of an afternoon. The LiPo flew for 41.5 minutes, whereas the much more energy dense lithium ion battery flew for 36.5 minutes. What’s going on here?

While the lithium ion battery has a much higher capacity, the problem here is the internal resistance of each battery chemistry. The end voltage for the LiPo was a bit lower than the lithium ion battery, suggesting the 18650 cells can be run down a bit further than [Tom]’s test protocol allowed. After recharging each of these batteries and doing a bit of math, [Tom] found the lithium ion batteries can fly for about twice as long as their LiPo counterparts. That means an incredibly long test of flying a plane in a circle over a field; not fun, but we are looking forward to other people replicating this experiment.

Continue reading “Lithium Ion Versus LiPoly In An Aeronautical Context” →

Dubai Police Test Quadcopter Motorcycle

October 16, 2017 by 69 Comments

If you ever wish you could be on your quadcopter when you fly it, you will really want to see the video showing the Dubai police department testing the Hoverbike. The Russian company Hoversurf that markets the device doesn’t provide a lot of technical details, but it looks fairly simple. It is basically a motorcycle seat along with a big quadcopter. From the videos about the device, you can deduce that the pilot can control it or you can fly it remotely. You can see one of the videos, below.

There are a few things that worry us here. Of course, the huge spinning propellers as the pilot’s knee level should give you sweaty palms. In the demo, they even show the removal of the propeller guards before the test flight but let’s be honest, those don’t look like they would keep a falling pilot out of the rotors at all anyway. When looking beyond the hype we find it curious that the demo doesn’t show many (if any) shots of the pilot making a turn. The benefit of a vehicle like this to police should be maneuverability and from what we saw the Hoversurf is still limited.

So is it real? Hard to say. The short videos mostly show vertical or horizontal flight with no maneuvering. Is it hard to turn? Is the battery life really short? One other oddity: When we first saw a letter from the US Patent Office on their site, we thought they might have some new technology. However, that letter is simply showing they registered a trademark and doesn’t reference a patent. If there is a patent we want to know what is new and novel here.

Of course, we know it’s possible to build such a machine since we saw [Colin Furze] do it with two rotors instead of four. The US Department of Defense is working on something with a company called Malloy and there are other practical examples. There are also some less practical examples. What we’re really on the lookout for is a product that works so well it will actually be used. You know, like those Segways that airport police use, right?

We hope Hoversurf can bring this to market because we definitely want one. There’s no reason to think they can’t, but we do wish there were more details forthcoming.

Where Can You Fly? Worldwide Drone Laws Mapped

September 26, 2017 by 10 Comments

If you are a flier of a multirotor, or drone, you should be painfully aware of the regulations surrounding them wherever you live, as well as the misinformation and sometime bizarre levels of hysteria from uninformed people over their use.

Should you travel with your drone, you will also probably be resigned to being interrogated by airport staff high on The War On Terror security theatre, and you’ll probably not find it surprising that they have little idea of the laws and regulations over which they have pulled you aside. It’s a confusing situation, and it’s one that [Anil Polat] has addressed by collating information about drone laws worldwide, and presenting his results on a Google map.

To do this must have been a huge undertaking, particularly since he got in touch with the appropriate authorities to access the information from the horse’s mouth. Looking at the map, we can almost view the green, yellow, and red pins showing different levels of restriction on flight as a fascinating indication of differing levels of security paranoia worldwide. If your territory has an orange or red pin, our commiseration.

This is a useful resource for anyone with an interest in multirotor flying, and he has also made it available as an app. However, it is always safest to check with the authorities concerned before flying in another territory, in case any laws have changed.

Here at Hackaday we’ve held an interest in the interface between multirotor fliers, governments, and the general public for a while now. In 2015 we took a look at FAA regulations for example, and last year we examined the inaccuracies in British air incident reports.

Via Adafruit.

Delivery Drone Aims To Make Package Handoffs Safer Than Ever

September 15, 2017 by 18 Comments

Picture this: you’re at home and you hear a rapping on your door. At last!– your parcel has arrived. You open the door, snatch a drone out of the air, fold it up, remove your package, unfold it and set it down only for it to take off on its merry way. Hand-delivery courier drones might be just over the horizon.

Designed in the [Laboratory of Intelligent Systems] at Switzerland’s École Polytechnique Fédérale de Lausanne and funded by [NCCR Robotics], this delivery drone comes equipped with its own collapsible carbon fibre shield — it fold up small enough to fit in a backpack — and is able to carry packages such as letters, small parcels, and first aid supplies up to 500 g and to 2 km away!

Continue reading “Delivery Drone Aims To Make Package Handoffs Safer Than Ever” →

Duocopter Does It With Two Fewer Propellers

July 25, 2017 by 15 Comments

Quads are a great ‘copter design. The paired blades counteract each others’ torque, and varying the relative speeds of the four motors makes it easy to steer. But what if you could get by with fewer blades, substituting a significantly fancier control algorithm?

[Dirk Brunner]’s DuoCopter drone uses two propellers that counter-rotate, and it steers by increasing and decreasing the speed at which the blades rotate within a single revolution. Spinning faster on one side than the other makes it tilt. Saying this is one thing, but getting the real-time control algorithms up and running is another. From the video embedded below, it looks like [Dirk] has it working. (He also holds the world’s record for fastest quadcopter ascent, FWIW.)

Of course some of you out there won’t be satisfied until your ‘copter has only one propeller. Or maybe you’d prefer a third prop. Whatever your taste, we’re stoked to see people pushing the boundaries of copter design.

Continue reading “Duocopter Does It With Two Fewer Propellers” →