Hacklet 68 – Rocket Projects

There’s just something amazing about counting down and watching a rocket lift off the pad, soaring high into the sky. The excitement is multiplied when the rocket is one you built yourself. Amateur rocketry has been inspiring hackers and engineers for centuries. In the USA, modern amateur rocketry gained popularity after Sputnik-1, continuing on through the space race. Much of this history captured in the book Rocket Boys by Homer Hickam, which is well worth a read. This week’s Hacklet is dedicated to some of the best rocketry projects on Hackaday.io!

rocket1We start with [Sagar] and Guided Rocket. [Sagar] is building a rocket with a self stabilization system. Many projects use articulated fins for this, and [Sagar] plans to add fins in the future, but he’s starting with an articulated rocket motor. The motor sits inside a gimbal, which allows it to tilt about 10 degrees in any direction. An Arduino is the brain of the system. The Arduino gathers data from a MPU6050 IMU sensor, then determines how to steer the rocket motor. Steering is accomplished with a couple of micro servos connected to the gimbal.

 

rocket2Next up is [Howie], with Homemade rocket engine. [Howie] is cooking some seriously hot stuff on his stove. Rocket candy to be precise, similar to the fuel [Homer Hickam] wrote about in Rocket Boys. This solid fuel is so named because one of the main ingredients is sugar. The other main ingredient is stump remover, or potassium nitrate. Everything is mixed and heated together on a skillet for about 30 minutes, then pushed into rocket engine tubes. It goes without saying that you shouldn’t try this one at home unless you’re really sure of what you’re doing!

 

rocket3Everyone wants to know how high their rocket went. [Vcazan] created AltiRocket to record acceleration and altitude data. AltiRocket also transmits the data to the ground via a radio link. An Arduino Nano keeps things light. A BMP108 barometric sensor captures pressure data, which is easily converted into altitude. Launch forces are captured by a 3 Axis accelerometer. A tiny LiPo battery provides power. The entire system is only 23 grams! [Vcazan] has already flown AltiRocket, collecting data from several flights earlier this summer.

 

rocket4Finally we have [J. M. Hopkins] who is working on a huge project to do just about everything! High Power Experimental Rocket Platform includes designing and building everything from the rocket fuel, to the rocket itself, to a GPS guided parachute recovery system. [J. M. Hopkins] has already accomplished two of his goals, making his own fuel and testing nozzle designs. The electronics package to be included on the rocket is impressive, including a GPS, IMU, barometric, and temperature sensors. Data will be sent back to the ground by a 70cm transceiver. The ground station will use a high gain human-guided yagi tracking antenna with a low noise amplifier to pick up the signal.

If you want more rocketry goodness, check out our brand new rocket project list! Rocket projects move fast, if I missed yours as it streaked by, don’t hesitate to drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

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.

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I Love The Smell Of Rocket Candy In The Morning

[Grant Thompson aka “The King of Random”] has created a great tutorial on making sugar rocket motors. [Grant] is using a fuel based on potassium nitrate and sugar. Known as Rocket Candy or R-Candy in the amateur rocket community, various forms of this mixture have been used for decades. In fact, this is similar to one of the mixtures [Homer Hickam] and friends used to build rockets in his novel Rocket Boys.

[Grant] bought a cheap blender from the thrift store, which he used to grind his ingredients. You probably won’t want to use this blender for food after it’s been full of KNO3-based stump remover. The blender made quick work of grinding down the KNO3 to a fine powder. [Grant] then added in powdered sugar and carefully mixed the two by shaking, not by running the blender.

A 5″ length of schedule 40 PVC pipe made the rocket motor casing. The rocket motor’s end caps are made from ground clay cat litter. [Grant] rams the layers with a wooden dowel and hammer. First a top cap of clay, then the rocket fuel, then a bottom cap also of clay. With all the layers in place, he hand drilled a hole through the bottom cap and the entire fuel layer. Drilling all the way through turns the motor into a core burning rocket. The entire fuel cylinder burns away from the inside out, with more surface area than burning the end alone.

[Grant] tested his rocket motor at a remote location. We probably would have gone with an electric igniter rather than a fireworks style fuse, but the end result is the same. The rocket motor performed admirably, blasting up to over 2000 feet in altitude.

It goes without saying that working with solid rocket fuel isn’t something to be taken lightly. Something as simple as an air gap in the fuel could lead to a CATO, turning this rocket motor into a pipe bomb. We echo [Grant’s] suggestion to search for local amateur rocket clubs before trying this one at home.

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