UAV Coaxial Copter Uses Unique Drive Mechanism

Personal UAV’s are becoming ubiquitous these days, but there is still much room for improvement. Researchers at [Modlab] understand this, and they’ve come up with a very unique method of controlling pitch, yaw, and roll for a coaxial ‘copter using only the two drive motors.

In order to control all of these variables with only two motors, you generally need a mechanism that adjusts the pitch of the propeller blades. Usually this is done by mounting a couple of tiny servos to the ‘copter. The servos are hooked up to the propellers with mechanical linkages so the pitch of the propellers can be adjusted on the fly. This works fine but it’s costly, complicated, and adds weight to the vehicle.

[Modlab’s] system does away with the linkages and extra servos. They are able to control the pitch of their propellers using just the two drive motors. The propellers are connected to the motors using a custom 3D printed rotor hub. This hub is specifically designed to couple blade lead-and-lag oscillations to a change in blade pitch. Rather than drive the motors with a constant amount of torque, [Modlab] adds a sinusoidal component in phase with the current speed of the motor. This allows the system to adjust the pitch of the blades multiple times per rotation, even at these high speeds.

Be sure to watch the demonstration video below. Continue reading “UAV Coaxial Copter Uses Unique Drive Mechanism”

Quadcopter Beer Delivery System

One of the major design challenges when it comes to building an efficient quadcopter is weight. The idea here is that the more you can trim down the weight of the frame, motors, and circuitry, the longer the batteries will last. Or, in [dalbyman]’s case, the more beer it can carry.

[Dalbyman]’s housemate built the actual quadcopter, but then [dalbyman] got a little inebriated and decided that, while the quadcopter was exciting on its own, it would be even better with this modification. The actual device is a modified Pringles can with two servo motors on the bottom with arms that hold the beer. A parachute is attached to the beverage can and the assembly is loaded in. With a simple press of a button, the servos turn the arms and the beer falls out of the tube. Hopefully the parachute deploys and gently (and accurately) floats the beer to the thirsty person on the ground!

This project is a simple step that goes a long way towards a beer delivery system even Amazon could be proud of, and also shows off the capabilities of quadcopters in general. Perhaps the next step could be to automate the beer delivery system!


Reverse Engineering the Proto X Quadcopter Radio

Just a few years ago, palm sized radio controlled toys were nothing more than a dream. Today, you can find them at every mall, toy store, and hobby shop. [Alvaro] couldn’t resist the tiny Estes Proto X quadcopter. While he enjoyed flying the Proto X, he found that the tiny controller left quite a bit to be desired. Not a problem for [Alvaro], as he embarked on a project to reverse engineer the little quad.

Inside the quadcopter and its lilliputian radio, [Alvaro] found a STM8 based processor and an Amiccom A7105 2.4G FSK/GFSK Transceiver radio. The A7105 is well documented, with datasheets easily obtained on the internet.  The interface between the processor and the radio chip was the perfect place to start a reverse engineering effort.

With the help of his Saleae logic analyzer, [Alvaro] was able to capture SPI data from both the quadcopter and the transmitter as the two negotiated a connection. The resulting hex files weren’t very useful, so [Alvaro] wrote a couple of Python scripts to decode the data. By operating each control during his captures, [Alvaro] was able to reverse engineer the Proto X’s control protocol. He tested this by removing the microcontroller from the remote control unit and wiring the A7105 to a STM32F4 dev board. Connecting the STM32 to his computer via USB, [Alvaro] was able to command the quad to take off. It wasn’t a very graceful flight, but it did prove that his grafted control system worked. With basic controls covered, [Alvaro] knocked up a quick user interface on his computer. He’s now able to fly the quadcopter around using keyboard and mouse. Not only did this prove the control system worked, it also showed how hard it is to fly a real aircraft (even a tiny model) with FPS controls.

The Estes Proto X is actually manufactured by Hubsan, a China based manufacturer best known for the x4 series of mini quadcopters. Since the Proto X and the x4 share the same communication protocol, [Alvaro’s] work can be applied to both. With fully computer controlled quads available for under $30 USD, we’re only a few cameras (and a heck of a lot of coding) away from cooperative drone swarms akin to those found in the University of Pennsylvania GRASP Lab.

Continue reading “Reverse Engineering the Proto X Quadcopter Radio”

An Extremely Tiny 5.8GHz FPV Transmitter

Flying RC aircraft with a first person view is the latest and greatest thing in the hobby. In a fact that I’m sure will be shocking to 90% of people, you don’t need to buy a Phantom quad fly FPV. The guys at Flite Test show how you can build a tiny 5.8GHz FPV transmitter for under $100.

The parts used for this build are pretty much jelly bean parts at this point, but [Peter] at Flite Test is going for extremely lightweight parts for this build. He found an NTSC board camera that only weighs 1g and added a wide-angle lens. The transmitter is a tiny 200mW module that only weighs about 2g.

Why are the Flite Test crew going for small and light FPV setups? They just launched a new line of planes that can be built from a single piece of foam board. If you have a small micro quad, you can easily add FPV to it with this rig.

3D Printed Drone Follows the Leader

[peabody124, aka James] has been active in the drone world for several years now, first with OpenPilot, then TauLabs, and now with his own Spark and Sparky2 boards. [James]’ latest creation is a 3D printed quadcopter using both his Sparky2 board and his Sparky2BGC Brushless Gimbal Controller.

[James] had always wanted a quad which would follow him and his friends while they were having fun, sort of like his own flying camera platform. His current setup is finally approaching that goal. [James] designed his new quadcopter to use his Sparky2 flight controller and the KISS 18 amp Electronic Speed Controller (ESC). He also incorporated a brushless gimbal to keep his Mobius action cam pointed at a whatever the drone may be tracking.

To keep the internal intern-boardslayout clean, [James] designed a power distribution board which solders right up to the ESCs. The internal layout is seriously clean, with flat panels which keep the electronics safe during crashes.

The crash protection turned out to come in handy, as [James] managed to hit a couple of drone-eating trees during testing. Thankfully, having a 3D printed quad means spare parts are just a few hours of printing away. Check out the video below for footage of [James]’ test flights, and of the quad tracking his cell phone via an RF link.

Continue reading “3D Printed Drone Follows the Leader”

DIY FPV Goggles Born From Necessity of Cheapness

So now that you’ve built your quadcopter and can fly it without crashing most of the time, what’s next? How about metaphorically hopping into the pilot’s seat with a First Person View setup. Great idea… but the cost of the required gear can be a deal breaker. FPV goggles alone range from the low to high hundreds. [sneaky] was using his laptop screen for his FPV setup and decided to try to make is own FPV goggles.

The display is just a small LCD screen that was purchased off eBay. Craft foam board was cut, bent, glued and duct taped to form a box about the same size as the LCD screen which is also secured to the box with duct tape. [sneaky] then cut the opposite side of the box to fit his face before he lined it with 1/2″ weatherstripping foam. Staring at an LCD screen just inches from your face is sure to cause some discomfort. A Fresnel lens inserted in between the user’s eyes and the LCD reduces eye strain to make long flights tolerable. The whole assembly is then held to your noggin via a recycled ski goggle strap.

In the end, [sneaky] likes his new goggles better than his old laptop screen and sun shade setup. The goggles aren’t too heavy and he can wear them comfortably for a while. We’ve seen a DIY FPV goggle setup in the past that uses individual lenses for each eye rather than one large Fresnel lens.

Controlling a Quadcopter with Gestures

[grassjelly] has been hard at work building a wearable device that uses gestures to control quadcopter motion. The goal of the project is to design a controller that allows the user to intuitively control the motion of a quadcopter. Based on the demonstration video below, we’d say they hit the nail on the head. The controller runs off an Arduino Pro Mini-5v powered by two small coin cell batteries. It contains an accelerometer and an ultrasonic distance sensor.

The controller allows the quadcopter to mimic the orientation of the user’s hand. The user holds their hand out in front of them, parallel to the floor. When the hand is tilted in any direction, the quadcopter copies the motion and will tilt the same way. The amount of pitch and roll is limited by software, likely preventing the user from over-correcting and crashing the machine. The user can also raise or lower their hand to control the altitude of the copter.

[grassjelly] has made all of the code and schematics available via github.