If you enjoy flying quadcopters, it is a good bet that you’ll have a drone with a camera. It used to be enough to record a video for later viewing, but these days you really want to see a live stream. The really cool setups have goggles so you can feel like you are actually in the cockpit. [Andi2345] decided to go one step further and build a drone that streams 3D video. You can see a video of the system, below.
Outdoors, there’s probably not a lot of advantage to having a 3D view, but it ought to be great for a small indoor drone. The problem is, of course, a small drone doesn’t have a lot of capacity for two cameras. The final product uses two cameras kept in sync with a sync separator IC and a microcontroller, while an analog switch intersperses the frames.
On the viewing side, a USB frame grabber and a Raspberry Pi splits the images again. At first, the system used an LCD screen married with a Google Cardboard-style goggle, but eventually, this became a custom Android application.
File this one under, ‘don’t do this yourself, but we’re glad they filmed it.’ [Denis Koryakin] flew a quadcopter to 10km, or about 33,000 feet. This was just an experiment to see if it was possible. A few items of note from the video: this thing was climbing at 14-15 m/s when it first took off. It was barely climbing at 2 m/s at 10km. Second: it was really, really cold. The ground temperature was -10 C, and temperatures at 8km reached -50 C. Density altitude is on this guy’s side, and I don’t know if this would be possible in warmer temperatures.
Hold on to your hats, there’s a gigantic space station that’s going to crash sometime in the next few weeks. Tiangong-1, an 8-ton space station launched in 2011, is going to reenter the atmosphere ‘sometime between March 30 and April 6’. Because of orbits and stuff, it’s more likely to reenter at the highest latitudes, and this space station has an inclination of 42.7 degrees. If your latitude is 42° N or 42° S, you should probably pull a Liza Minnelli on this situation and spend the next month in bed.
FREE CHIPS!. Free motor drivers, actually, which is even more impressive. Aisler puts together BOMs for projects and such — think of it as an on-demand kitting service. They’re throwing in free Trinamic drivers with orders. Someone should build a motor driver breakout.
Over at RCgroups, user [Cesco] has shared a very interesting project which uses the ever-popular ESP8266 as both a transmitter and receiver for RC vehicles. Interestingly, this code makes use of the ESP-Now protocol, which allows devices to create a mesh network without the overhead of full-blown WiFi. According to the Espressif documentation, this mode is akin to the low-power 2.4GHz communication used in wireless mice and keyboards, and is designed specifically for persistent, peer-to-peer connectivity.
Switching an ESP8266 between being a transmitter or receiver is as easy as commenting out a line in the source code and reflashing the firmware. One transmitter (referred to as the server in the source code) can command eight receiving ESP8266s simultaneously. [Cesco] specifically uses the example of long-range aircraft flying in formation; only coming out of the mesh network when it’s time to manually land each one.
[Cesco] has done experiments using both land and air vehicles. He shows off a very hefty looking tracked rover, as well as a quickly knocked together quadcopter. He warns the quadcopter flies like “a wet sponge”, but it does indeed fly with the ESP’s handling all the over the air communication.
To be clear, you still need a traditional PPM-compatible RC receiver and transmitter pair to use his code. The ESPs are simply handling the over-the-air communication. They aren’t directly responsible for taking user input or running the speed controls, for example.
We’ve seen some cheap quadcopter builds over the years, but this one takes the cake. After seeing somebody post a joke about building a quadcopter frame out of zip ties and hot glue, [IronMew] decided to try it for real. The final result is a micro quadcopter that actually flies half-way decently and seems to be fairly resistant to crash damage thanks to the flexible structure.
The first attempts at building the frame failed, as the zip ties (unsurprisingly) were too flexible and couldn’t support the weight of the motors. Eventually, [IronMew] realized that trying to replicate the traditional quadcopter frame design just wasn’t going to work. Rather than a body with arms radiating out to hold the motors, the layout he eventually came up with is essentially the reverse of a normal quadcopter frame.
Zip ties reinforced with a healthy coating of hot glue are arranged into a square, with a motor at each corner. Then four zip ties are used to support the central “pod” which holds the battery and electronics. No attempt is made to strengthen this part of the frame, and as such the heavy central pod hangs down a bit in flight. [IronMew] theorizes that this might actually be beneficial in the end, as he believes it could have a stabilizing effect when it comes time to record FPV video.
He mentions that he’s still struggling to get the PID values setup properly in the flight computer, but in the video after the break you can see that it’s flying fairly well for a first attempt. We wouldn’t recommend you tear into a bag of zip ties when it comes time to build your first quadcopter, but it does go to show that there’s plenty of room for experimentation.
Before you smash the “Post Comment” button with the fury of Zeus himself, we’re going to go ahead and say it: if you want to build a decent quadcopter, buy a commercial frame. They are usually one of the cheaper parts of the build, they’re very light for how strong they are, and replacement parts are easily available. While you could argue the cost of PLA/ABS filament is low enough now that printing it would be cheaper than buying, you aren’t going to be able to make a better quadcopter frame on a 3D printer than what’s available on the commercial market.
Of course, [Paweł] is hardly the first person to think about printing a quad frame. But he did give his design some extra consideration to try and overcome some of the shortcomings he noticed in existing 3D printed designs. For one, rather than have four separate arms that mount to a central chassis, his design has arms that go all the way across with a thick support that goes between the motors. The central chassis is also reassuringly thick, adding to the overall stiffness of the frame.
The key here is that [Paweł] printed all the parts with 2 mm thick walls. While that naturally equates to longer print times and greater overall weight, it’s probably more than worth it to make sure the frame doesn’t snap in half the first time it touches the ground.
Beyond the printed parts, all you need to assemble this frame are about a dozen M3 nuts and bolts. Overall, between the hardware and the plastic you’re looking at a total cost of under $5 USD. In the video below [Paweł] puts the frame through its paces doing some acrobatic maneuvers, and it looks like 5 bucks well spent to us.
The props are a fairly simple 3-bladed design, which were printed in both PETG and PLA. No major difference is noted between the two materials, and the quadcopter under test is able to fly with either. It was noted that the props perform particularly poorly in a crash, with all props failing even in the softest of crashes. We would recommend some eye (and body) protection when spinning these props up for the first time.
If you’re keen to try them out yourself, the STL file can be had here. The video notes that when printing 4 props, 2 must be reversed in the Y-axis to print a counter-rotating set of 4. The instructions used for creating propellers in Fusion3D are available here.
It’s a worthy experiment, and something we’d like to see more of. With a 3D printer, it’s possible to experiment with all manner of propeller designs, and we’d love to see the best and worst designs that are still capable of flight. We’ve also seen 3D printed props before, like this effort from [Anton].
The ESP8266, really showcasing its all-round prowess, hosts both a web server for a HTML5 based joystick and a Websockets server so that a client, such as a phone, could interact with it over a fast, low latency connection. Once the ESP8266 receives the input, it uses interrupts to generate the corresponding PPM (Pule Position Modulation) code which the RC receiver on the quadcopter can understand. Very cool!
What really makes this realtime(ish) control viable is Websockets, a protocol that basically allows you to flexibly exchange data over an “upgraded” HTTP connection without having to lug around headers each time you communicate. If you haven’t heard of Websockets you really should look really check out this library or even watch this video to see what you can achieve.
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