There’s a special type of satisfaction that comes from really understanding how something works at the end of a reverse engineering project. This grid above is the culmination of [Spencer's] effort to reverse engineer the IR protocol of a Propel ExecuHeli indoor helicopter toy.
The first thing he looked at was the three different controller channels which can be selected to allow multiple helicopters to be used in the same area. [Spencer] was surprised that they all used the same carrier frequency. The secret must be in the coded packets so his next challenge was to figure out how the data was being transmitted via the Infrared signal. It turns out the packets are using pulse-length coding (we were unfamiliar with this protocol but you can read a bit more about it here). The last piece of the puzzle was to capture packets produced by each unique change of the control module. With each bit (except for bit 11) accounted for he can now format his own codes for a controller replacement. Perhaps he’s looking to make the helicopter autonomous?
[Jack Crossfire] took one of those inexpensive indoor helicopters and made it autonomous. He didn’t replace the hardware used for the helicopter, but augmented it and patched into the remote control to make a base station.
The position feedback is provided in much the same way that the Wii remote is used as a pointing device. On the gaming console there is a bar that goes under the TV with two IR LEDs in it. This is monitored by an IR camera in the Wii remote and used to calculate where you’re pointing the thing. [Jack's] auto-pilot system uses two Logitech webcams with IR filters over the sensors. You can see them mounted on the horizontal bar in the cutout above. The helicopter itself has an IR LED added to it that is always on. The base station follows this beacon by moving the cameras with a pair of servo motors, calculating position and using it when sending commands to the remote control’s PCB.
Don’t miss the demo video of the rig after the break.
Continue reading “Autonomous helicopter works like a Wii remote”
There’s a reason we’ve seen a menagerie of quadcopters over the past few years – the key piece of any quadcopter build is an inertial measurement unit. Historically a very complicated and expensive piece of kit, these IMUs came down in price a few years back, allowing anyone with a few dollars in their pocket and a handful of brushless motors to build a four-bladed drone in their workshop.
[Starlino] built a few quadcopters, but he wanted to shy away from IMUs and get most of the mass of his new ‘copter over the center of the chassis. He came up with a design he calls the quadhybrid that can be built out of a quartet of those cheap 3-channel helicopter toys.
Most of the lift for [Starlino]‘s quadhybrid comes from a pair of coaxial rotors from a Syma 001 3-channel helicopter toy. Anyone who has played with one of these toy helicopters knows how stable they are; if the tail rotor breaks, you’re left with a helicopter that can only go up and down.
To give his quadhybrid a few degrees of freedom, he attached four tail rotors from 3-channel helis to a few booms laid out in a cross pattern. By taking the receiver out of a 4-channel helicopter and adding his own controller board, [Starlino] made each of the tail rotors control the pitch and roll of the craft.
In the video after the break, you can see the quadhybrid is amazingly stable even without an IMU and surprisingly agile. As [Starlino]‘s ‘copter can be made out of replacement parts for cheap 3-channel helis, we’ll expect a rush on these tail motors at your favorite online RC retailer very shortly.
Continue reading “Turning four smaller helicopters into one larger quadcopter”
Half the fun of buying toys for your kids is getting your hands on them when they no longer play with them. [Kerry Wong] seems to be in this boat. He bought a Syma S107G helicopter for his son. The flying toy is IR controlled and he reverse engineered the protocol it uses. This isn’t the first time we’ve seen this type of thing with the toy. In fact, we already know the protocol has been sniffed and there is even a jammer project floating around out there. But we took a good look at this because of what you can learn from [Kerry's] process.
He starts by connecting an IR photo diode to his oscilloscope. This gave him the timing between commands and allowed him to verify that the signals are encoded in a 38 kHz carrier signal. He then switched over to an IR module designed to demodulate this frequency. From there he captures and graphs all of the possible control configuration, establishing a timing and command set for the device. He finishes it off by building a replacement controller based on an Arduino. You can see a video of that hardware after the break.
Continue reading “Reverse engineering a Syma 107 toy helicopter IR protocol”
These guys make your own video editing chops look just plain sad. They put together a video demonstrating the portal gun in real life.
Unleashing the beast
We have this problem all the time. The noise regulations were preventing [Massimiliano Rivetti] from letting the true voice of his Ferrari be heard. He hacked into the control system and can now adjust it via iPhone to roar with power. [Thanks Claudio via openPicus]
Music so bad you want to throw something
Here’s a novel way to include the worker bees in music selection around the office. A piezo element was attached to the back of a framed poster and when you throw something at it, the next track is played. We really loved the demo video for this one. [Thanks Calum via DontBelieveTheHype]
Acrylic frame for a CNC machine
[Jake] wrote in to show off his progress on a CNC build. He’s got a frame made of acrylic and some other materials. It’s not up and running yet, but what he’s got so far looks very nice.
Helo built for one
All we can think with this one-man helicopter is failure of those propellers. At least with an ultralight plane you can glide to a gentler crash-landing. [Thanks Filespace]
His goal of one post a week for a year has past, but [Dino] keeps bringing his skills to bear on new projects. This time around he’s adding a wireless camera to an RC helicopter.
These radio controlled fliers (there are cheap ones that use IR control which is much less reliable) can be found for around $30-60. [Dino] already had a wireless camera to use, but adding it and a 9V battery is just too much weight to lift. After some testing he established that 2oz of payload is the upper limit. He began removing parts from the helicopter to achieve enough savings to lift both the camera and its battery. Along the way he discovered that removing the weights from the fly bar added a lot of maneuverability at the cost of a small stability loss.
Check out his project video embedded after the break. It’s not anywhere near the results of professional multi-rotor camera mounts, but it is cheap and fun!
Continue reading “Building your own eye in the sky”
Cool picture, huh? Wait until you see the video footage of this LED-adorned RC helicopter flying on a dark night. But this isn’t an art project. Analyzing the long-exposure photography turns out to be a great way of clearing up some of the physics of flight which otherwise are not at all intuitive. The helicopter used here has different colored lights on the nose and tail, as well as lights on the rotors.
Depending on how the aircraft is moving, different 3D spirography is captured by the camera. When you zoom in on part of the flight path it becomes clear that there are wider arcs on one side of the fuselage than there are on the other. This has to do with the forward progress of the aircraft and the rotation of the blades. The phenomenon is well known by helicopter enthusiasts, and accounted for in the design. But what we didn’t realize is that it actually translates to a theoretical speed limit for the aircraft. Our childhood love of Airwolf – the TV helicopter that could outrun jets — has been deflated.
You should remember the helicopter physics videos featured here last month. This is the latest offering and we’re still wanting more!
Continue reading “Helicopter light painting continues to snuff out physics lesson on your brain”