K.C.'s Garage

I had the EDFs mounted to the frame with zip ties for the first test.  That proved a bit unstable.  I also had the problem of the motor housings sticking down lower than the rest of the quad, which posted a threat to them on landing. Talon motor mount So, I decided to kill two birds with one stone by making some EDF mount brackets that extended vertically below the bottom of the motor housings.  The Turnigy Talon frame I used included these aluminum "T" mounts, intended to be mounted horizontally at the end of the tubular arms to allow you to mount the motor on top.  I simply turned them 90 degrees so that the flat face was vertical to align them with one of the two flanges protruding from the side of the EDF housings. To mount the EDF flanges to them, I fabricated a mounting bracket to use as a clamp.  I used an old license plate frame that I cut into four equal length parts and drilled matching holes in: Four mounts cut from a discarded license pla...

I decided, against conventional "wisdom", to construct a quadcopter that uses Electric Ducted Fans (EDFs) for thrust.  There is conjecture all over the internet as to why this is a bad idea, but I was having a hard time finding any real science or performance data to back it up.  So, why not build one and see what happens? What are EDFs? EDFs are basically small, higher pitch, higher rpm propellers (sometimes called "impellers" in this application, to differentiate them from conventional propeller design) inside a cylindrical duct with a tapered inlet and as little clearance between the blades and the duct wall as possible.  They look more like jet engines than conventional propellers.  Tangent: Modern jet engines actually are turbine driven ducted fans, called " turbofans ." The primary benefit of a ducted fan is increased efficiency of the propeller by preventing (or reducing) the phenomenon of "tip vorticies" and allowing a greater ra...

A common question I get is:  "What MultiWii flight controller should I use?" There are a few determining factors involved in this decision.  The primary considerations are: What microcontroller (µC) do you need What integrated sensors do you want? What Microcontroller (µC) should you look for? MultiWii is based on the Atmel corporation's 8 bit "megaAVR" series of µCs.  All the MultiWii boards I've seen are based on one of three µCs, but you could certainly port the software to others if you're good at microcontroller integration. Below is a table of the three most common and their relevant specifications: µC flash ram eeprom serial uarts usb ports ATmega328p 32 kilobytes 2048 bytes 1024 bytes 1 0 ATmega32u4 32 kilobytes 2560 bytes 1024 bytes 1 1 ATmega2560 256 kilobytes 8192 bytes 4096 bytes 4 1 Those of you who are familiar with AVR µCs will notice I left off the number of digital, ...

Meet "Sharky", my first non-indoor quadcopter.   (Shown next to one of my brushed-motor nano quads for scale.) I wanted to graduate to a larger quad, but not something huge, so I decided this 345mm span "mini" quad was the way to go.  I liked the size and design of this quad. The "pseudo-airplane" shape on the frame looked more like a shark than an aircraft to me, hence the name. We'll start with what I initially built: Frame: Turnigy Integrated PCB Mini-Quad 345mm Flight Controller:  MultiWii MicroWii ATmega32U4 Flight Controller USB/BARO/ACC/MAG Receiver:  OrangeRx R100 Spektrum/JR DSM2 Compatible Satellite Receiver 4 x Motors:  Turnigy Park300 Brushless Outrunner 1380kv 4 x Speed Controllers (ESCs):  Afro ESC 12Amp (SimonK Firmware) Battery:  ZIPPY Compact 2200mAh 3S 25C Lipo Pack Props: GWS HD8040 3 blade (& their counter rotating counterparts ) I fly this with my existing OrangeRX T-Six DSM2 transmitter. I run MultiWii 2....

Anyone who knows me well knows that lately I've been playing with remote-controlled flying things.   This post provides information and links to the small (nano) indoor flyable quadcopters I've been playing with. I have built & modified a few quadcopters of various (small) sizes, from the tiny brushed-motor nano-quads like the HobbyKing Pocketquad & Syma X1 to a larger, more traditional brushless motor mini quad based on the Turnigy 345mm frame.  (More on that in a subsequent post.) Throughout this endeavor I've been using (and customizing) the MultiWii flight control software , with various Arduino / Atmel-based flight control boards.  It's becoming a FAQ what hardware and systems I'm using, so in this post I'll detail my current setup.  Future posts will cover updates, new hardware, and a couple of crazy projects I'm working on.  ;) Note: I buy a lot of parts made and sold by HobbyKing.com in China.  Their website is a bit... odd.. so I...

Sometimes, you just yearn to see things the way they looked online in 1985, you know?  Maybe you don't.  But in case you get into an argument with someone over whether that modem video you posted "looks more like 110 baud than 300 baud" you can whip out this little python script and pipe some unix commands through it to relive the glory days.  When men were men and online-p0rn was ASCII ART. #!/usr/bin/python2.7 import sys from time import sleep def modem(text, speed):   # Assume speed is in bits/sec, and we're running at 8,N,1   # So, 10 bits per character.  (1 start, 8 char, 1 stop)   delay = 1.0 / (speed / 10)  # = seconds per character   for char in text:     sys.stdout.write(char)     sys.stdout.flush()     sleep(delay) if __name__ == "__main__":   if len(sys.argv) > 1:     baud = int(sys.argv[1])   else:     baud = 300   for ln in sys.stdin: ...

The 2010 Dodge Caravan SXT I recently acquired has an interesting feature - a built in "Vehicle Entertainment System" complete with two rear screens, two DVD players, two aux video/audio inputs, and multi-channel IR headphones. This is all cool, but who wants to be stuck watching things they happen to be carrying around on DVD?  This is 2013, the age of streaming media!  Immediately, I started pondering how I could bring this system up to date with the current state of ADD-inducing, "always-on" streaming media entertainment! I. Video in Motion First thing's first.  The Chrysler/GM "MyGig" system has a Lawyer-induced feature of disabling any video from the head unit when you put the vehicle in drive.  That's rather annoying!  I don't condone watching a movie while you're supposed to be driving, but I'd rather that I dictate to the technology what to do, not the other way around.  Thankfully, there are a couple of companies that mak...