The timer is built using four small inexpensive CMOS integrated circuits. This allows it to run on just 3V from two small AAA batteries. U1 is a 74HC688 8-bit equality comparator. It compares the switch settings to the counter output and will set pin U1-19 low when they match. The actual counter is U2. It is a 74HC4060 14-stage binary ripple counter with built-in oscillator.
The G-switch itself uses a cantilevered metal bar that pivots down as the rocket accelerates upward. The metal bar actuates a small micro-switch that triggers a digital counter to begin the timing sequence. The timer is designed so that it will not start unless the micro-switch has been activated for a duration of at least 0.5 seconds.
G-switch timer – Vern Knowles – The timer was built using a small prototyping circuit board and point-to-point wiring.
U3 is a 74HC74 D-type flip-flop that is used as part of the triggering logic. U3-12 will be low when the counter matches the switch settings. Consequently, on the next oscillator clock edge from U2-9 the flip-flop output at U3-9 will go low. This is the event that activates the 2N4403 transistor that fires the flash bulb.
Source code and many notes used in Vicacopter, the 1st English language source code for a fully functional helicopter autopilot.
Vicacopter – Open Flight Robotics
Vicacopter uses a ground computer for flight control. An 8 bit airborne microcontroller handles rate damping, PWM, & sensor capturing. The ground computer handles navigation & provides a simple instrument panel. This was the cheapest & most flexible way to fly. The system can be converted to a completely airborne autopilot very simply.
- Automated landing & takeoff
- Sonar position sensing for indoor flight
- GPS position sensing for outdoor flight
- Ground station instrument panel
- Untethered communication from pilot to ground station
- Curved or linear paths
The Tri-Roter one used 3 gyros for short term rotation sensing, 2 accelerometers for long term tilt sensing, 3 magnetometers for long term heading sensing, a high quality GPS module for horizontal position, a barometer for altitude sensing. A 3rd accelerometer was too sensitive to vibration & altitude changes to be any good. Because of the long term sensors & the very stable gyros, the orientation was always pretty accurate & didn’t drift.
His planes include those created for his grand-children. “Amazing Paper Airplanes” has the clear folding instructions for all types. Some are flying types and some can make impressive DIY Decor.
The Paper Airplanes of Kyong Hwa Lee
Start with Simple Plane Designs for beginners include traditional paper airplanes.
The Basic Dart shown on right is probably the most well known paper airplane in the world. It is simple, easy to fold, and flies fast and far. It may have a slight tendency to nose-dive, but it can be corrected by bending the trailing edges of the wings upwards.
Gyroscope.com – Gyroscopes Educational Gadgets
“Gyroscope.com has been in existence since 1999, we were inspired to set up a web site dedicated to all things gyroscope after an attempt to purchase a single toy gyroscope.”
Super Precision Gyroscope
The Super Precision Gyroscope is an all new gyroscope, designed and built to the highest precision from the very start. Made from SOLID brass and aluminium with carefully chosen miniature high-grade bearings.
Tedco Original Toy Gyroscope
This gyroscope was first produced in 1917 under the name of ‘Chandler gyroscope’. It has remained relatively unchanged and has been a classic educational toy for generations. It continues to fascinate young and old alike with its mysterious force that seems to defy gravity. Whether you just want to have hours of fun with it just as a toy or whether you want to learn more about physics/science of gyroscopes.
This site is for flyers of Radio Controlled model aircraft wanting to find out about successful Electric powered RC modelling.
Fly Electric– Radio Controlled Model Aircraft
“On this site I showcase big electric planes, have loads of free plans for smaller ones, cover many interesting contruction topics and provide circuit diagrams and advice for lithium batteries.” – David Theunissen
PIC and AVR Projects – Designing PIC microcontroller-based devices to monitor lithium voltages. Individual cell low voltage cutoff, lithium tester and servo controller circuits. Simple data logging. Tutorials to help beginners to get started.
Brushless Free-Flight Timer – The page describes how to convert a cheap commercial speed controller into a light, easy to use, brushless free flight timer. It is also a good introduction to brushless ESC’s and you could even build your own.
KD7LMO amateur radio and open source hardware
Nixie Tube Clock
“In the pioneering sprit of amateur radio and open source hardware and software, I’ve assembled a collection of information and engineering plans for a variety of amateur radio projects. These projects cover a wide range of disciplines.” – KD7LMO
From the GNU radio web site
“GNU Radio is a collection of software that when combined with minimal hardware, allows the construction of radios where the actual waveforms transmitted and received are defined by software.
What this means is that it turns the digital modulation schemes used in today’s high performance wireless devices into software problems.”
The latest in SDR (Software Defined Radio) technology. Here are some projects and information that rely on the GNU Radio and USRP (Universal Software Radio Peripheral).