Lauren loves confetti.

Several months ago, Lauren asked me if there were a way for us to drop confetti under the tent at our wedding reception. Confetti machines for weddings were really expensive to buy (read: around $6000), but she imagined I could build something where the confetti would be trapped like balloons under a net and gently be released upon the unsuspecting wedding guests.

Gently? I had other ideas. Over on the Make Blog, one of the How-To Tuesdays was this compressed air rocket launcher. Perfect. I was confident that I could turn it into our confetti launcher!

After a three hour adventure at Home Depot, some internet shopping at SparkFun, an evening of soldering, and an afternoon of gluing PVC together, I was ready for a small indoor test in our apartment. I shredded some newspaper as a substitute for the confetti and used our bicycle pump to “charge” it to about 20psi.

3-2-1. A push of the red button and poof! It rained “confetti.” And of course, there is video proof.

The Weller Portasol P2C. Soldering gone wireless. Butane instead of electricity. And it comes with a blow torch tip? I didn’t have anything that needed to be soldered, but that didn’t keep me from immediately trying it when it came in. I’ve wanted one of these ever since Andy brought one on our last trip.

For the record, Lauren must really trust me if she gets me a butane-powered blow torch in disguise for my birthday, and then let’s me play with it in our apartment. Thank you.

Ok, let’s take a closer look. Since the P2C is a butane-powered soldering iron, it needs butane fuel. Lauren thankfully ordered a 2.1oz can of it along with the P2C from ToolBarn.com.

The P2C comes with replaceable tips, a nozzle for refueling, a knob for butane gas flow adjustment, an on/off switch, and an ignition switch. It is made of a heat resistant plastic and is, therefore, light even when filled with butane.

Refueling the soldering iron with butane is easy. Hold the soldering iron upside down and mate the tip of the fuel can with the nozzle. Push down with the fuel can for three seconds at a time until it is full. The P2C also features a convenient window to see if you have any butane left.

The butane flow can be adjusted to provide the equivalent power of a 45W to 75W soldering iron.

The front assembly of the P2C can be removed, such that you can replace the tip with any of the Weller Portasol tips. The P2C kit included a 0.094″ double sided soldering tip, a hot air tip with deflector, a hot knife tip, and the blow torch tip shown in the photo.

I cannot wait to put the P2C to good use. Hopefully I will get a chance to do just that on our trip to Ft. Benning, GA to test the autonomous mode of our Flying Android UAV.

If you are curious, check out my Flickr set for more photos of the P2C.

After two grueling months, the wait was finally over. A large, but light, package had arrived in the mail taped shut at one end with Atlantahobby.com packaging tape. Lauren had ordered it for me months ago for our engagement anniversary, but every hobby shop locally and online had it back ordered until the middle of February. It took time for it to travel overseas from Germany.

This weekend it made it here. It took great restraint, but I waited until the next day to open the package. I wanted to make sure I had enough daylight to photo document it, and that is what I did.

I swiftly used my Swiss Army knife to dispose of the packaging. Its contents were what I had been waiting for all this time; my very own Multiplex EasyStar R/C airplane. This is the same aircraft used by the developers of the ArduPilot and our platform for the Flying Android project.

The EasyStar is an ideal platform for learning how to fly R/C airplanes, plus it is actively used for aerial robotics. I plan to pursue both as soon as we leave the unfriendly winter weather behind.

The Multiplex EasyStar comes as a Ready-to-Fly (RTF) kit, so there was little for me to build once I had it unpacked. The Hitec 72Mhz 4-channel single stick transmitter needed eight AA batteries. Replacing the batteries required taking apart the entire transmitter; therefore, rechargeable NiCd batteries should be a wise investment.

Inside of the fuselage is the Hitec 72Mhz 6-channel receiver. Only three of the channels are used on the transmitter and receiver: one for the throttle, one for the elevator, and one for the rudder. This leaves the fourth channel open for customization, which we use for toggling the autopilot on/off on our Flying Android EasyStar. Next to the receiver is the electronic speed controller (ESC) and a NiCd battery pack can be found in the nose of the airplane.

The assembly required to put this airplane together merely took ten minutes. The elevator is glued to the tail and attached to one servo, while the rudder is glued on top of the elevator and attached to the other servo. The wings are joined by a plastic rod and can be easily attached and detached from the aircraft.

I was ready to test the servos and throttle in no time. First, I turned on the transmitter and then the receiver (and vice versa when powering off), else I could risk damaging the servos or other electronics. Then, I verified that the trims and stick moved the control surfaces in the correct directions. Finally, the throttle needed to be tested, so I ramped it up to full power!

I have already started to make a list of modifications in my head: switching over to the 2.4Ghz transmitter from the Blade CX2 helicopter, a brushless DC motor and ESC for more power, and a LiPo battery pack for longer flights. Plus, a camera module is definitely a must.

Make sure to check out my Flickr set for more photos.

Photo of Wednesday, the black cat, is © Lauren Riddle.

This is part two of a seemingly endless series of tutorials on how to undo what your cat (or other pet) loves to do. Today’s “Fix it” tutorial covers the repair of the Nintendo Wii sensor bar and its connector cable, which can be severed by the first molars of a black cat in under two seconds.

Scenario

The cable connecting the sensor bar to your Wii has been damaged or severed. You don’t want to spend $7.50 to get a refurbished one or $20 to get the new wireless sensor bar; however, you are brave and confident that you can fix it yourself.

What you will need

This tutorial will require the same basic tools as before:

• A soldering iron
• A spool of thin solder
• A wire stripper
• Some heat shrink tubing

You can find heat shrink tubing almost anywhere. Make sure to pick up heat shrink tubing that is just a little bit larger than the cable itself, so that it will fit tightly after it shrinks.

Before we get started

Since this tutorial requires some soldering, cutting, and heating, please make sure to be safe! Nothing here is dangerous so long as you use the tools properly and stay focused.

Step 1

Your cable may look a little like the included photo when you start. If your cable is damaged, but not completely severed, you will need to cut through it.

Use your wire stripper to cut away the damaged sections of the cable before you start the repair. The connector cable will get shorter, so make sure to save as much of it as you can.

Continue reading “Fix it: Nintendo Wii Sensor Bar” »

Photo of Wednesday, the black cat, is © Lauren Riddle.

Our black cat, Wednesday, has a cat tree, a feather boa, and all the mice a cat could ever ask for, but her favorite toy to destroy turns out to be cables. Yes, cables. She will chew through headphones, Wii sensor bars, and my Xbox 360 headset. If your cat, or another wild animal you choose to keep in your home, decides to destroy your headset, this “fix-it” tutorial will help you repair the damage.

Scenario

The cables on your Xbox 360 headset have been damaged or severed. You don’t want to spend $20 to replace it and are brave and confident that you can fix it yourself.

What you will need

These are household items familiar to anyone who has ever taken apart and fixed any electronics. If this is your first attempt, don’t worry, you can easily learn how to use them.

• A soldering iron
• A spool of thin solder
• A wire stripper
• Some instant glue

If you are missing a particular item, you can easily purchase it cheaply from most electronics stores. I have included links to these items in the SparkFun store. They’re both cheap and great for beginners! Plus, you’ll get to reuse them on your future electronics projects.

Before we get started

If this is your first time soldering, I recommend reading the SparkFun tutorial, including its safety tips! This tutorial will describe how to fix the cable below the volume control; however, fixing the cable above the volume control is almost exactly the same.

Step 1

If the cable hasn’t been completely severed, then you’ll need to make a cut. Your wire stripper can dual as a wire cutter, so use it to cut the cable right below the damaged area. You should have two pieces: the cable with the plug at one end, and the rest of the headset.

If your headset was damaged above the volume control unit, you’ll want to cut the cable right above the damage. Make sure to cut as close to the damage, since we want to maximize the amount of cable that is left.

Continue reading “Fix it: Xbox 360 Headset” »

I have finally completed the jump onto the Google bandwagon by getting organized with Google Calendar and shrugging off that Google now knows that I have CS4641 Machine Learning on Tuesdays and Thursdays from 3:05pm to 4:25pm in the Klaus Advanced Computing building. Sooner or later all of our personal data will be in the “Cloud,” because who really wants to manually sync their calendars, documents, contacts, etc. over three or four devices? I know I don’t.

There is a link in the right sidebar to my Google Calendar, so that you can check when I have something planned or not. You may use it to catch me during the week, or just out of plain curiosity.

For the fellow KDE users out there, you can sync your Google calendar and contacts with Kontact (or Korganizer) using Akonadi. The Akonadi Google Resource did not make it into KDE 4.3, but it can easily be grabbed and install from the KDE SVN repositories.

svn co svn://anonsvn.kde.org/home/kde/trunk/extragear/pim/googledata googledata
cd googledata/
mkdir build
cd build/
cmake ../ -DCMAKE_INSTALL_PREFIX=`kde4-config --prefix`
make && make install

Once the resources have been installed, pull up the configuration window for Akonadi (either through the System Settings or the Akonadi Tray Utility). Click “Add…” and you should see the Akonadi Google Calendar Resource at the top.

Click “Ok” and then enter your Google account information in the dialog box that is opened. Confirm and close the Akonadi configuration window.

Next, open Kontact (or Korganizer). Click the plus symbol at top right of the calendar list.

Select “Akonadi (Provides access…” from the top of the list and click “Ok.” In the “Resource Configuration” dialog that opens, change the default label in the “Name:” field to something more useful and then click “Ok.”

You’re all done! You should be able to see your Google calendar and add, edit, or delete events. The Akonadi resource automatically performs a two-way sync of all events in the calendar; however, it is currently limited to only the first of your Google calendars. Hopefully, complete support for data synchronization with Google will be part of KDE 4.4.

Interesting fact: The instructions for setting up Google Sync on the Apple iPhone/iPod Touch involves Microsoft Exchange. Quite amusing.

A few years ago, my dad entrusted me with his E-Flite Blade CX2 R/C coaxial helicopter, because I became interested in making it fly autonomously. I had a free project in one of my CS courses and decided to build a stabilizing auto pilot for the helicopter around an Arduino Mini, but more on that in a later post.

The helicopter is fairly easy to control indoors, as soon as I figured out to stay way from the ground, the ceiling, or any furniture. Flying too close to any such obstacles creates turbulence and backwash, which make the helicopter difficult to control. This also makes it almost impossible to fly outdoors, even in low wind conditions. The helicopter is powerful enough to lift itself off the ground, but can carry only a small payload of extra electronics. However, it is a lot of fun to fly!

Since the helicopter belongs to my dad, I made sure to take good care of it, but small crashes are inevitable in test flights around the living room in a studio apartment. The worst crash that could happen is a power-on blade strike, where the blades strike an object while the throttle is not at 0%. Either the blades could shatter on impact, or worse the blades are stuck, which cause the DC motors to over-current the 4-in-1 control unit. As Murphy’s law dictates, just that happened to me.

The short in the control unit from the over-current remained well hidden, since there was neither a spark nor a small puff of smoke: the #1 sign for any electronics geek that something just broke. I didn’t know something went awfully wrong until the next time I tried to fly the helicopter.

Plug the battery pack into the control unit. Go. Turn on the transmitter. Go. But the transmitter wouldn’t associate with the receiver in the control unit, which simply blinked red and green. Ok, let’s try it again. Unplug everything. Plug the battery pack in and turn on the transmitter. Same red and green blinking. Oh, no. Panic. Let me read the manual. Rebinding? I tried to rebind the transmitter and receiver with the bind plug, but that didn’t fix it either!

I spent the afternoon frantically searching the Internet for a solution, until I came across a discussion about Blade CX2s and the ‘over-current’ problem. I soon learned that the control unit was lost and this could have been easily prevented with a fuse between the 4-in-1 control unit and the DC motors. A $5 fuse? Why wasn’t this included with the helicopter in the first place? Needless to say, I was a bit furious that I had to replace the $60 control unit.

So before you have to spend $60 to replace a destroyed 4-in-1 control unit, invest $5 in resettable fuses (EFLH1206 Over-Current Protection/PTC Fuse Harness). These positive temperature coefficient (PTC) devices are non-linear thermistors, which at some specified level of current break the circuit and disconnect the motors from the control unit. The fuses reset once the current drops off on the wire.

The resettable fuses need to be installed between the control unit and each motor (not the servos). Check the photo below to see what it should look like installed on your helicopter. The fuses will add some length to the wiring, but you can easily stow them away in the cockpit above the control unit.

If you’re lucky, you may have bought one of the newer Blade CX2s, which now ship with the fuses already installed. Either way, next time you get unlucky with a power-on blade strike, you won’t blow your fuse over having to replace the $60 control unit.

Lauren and I were ready for SparkFun‘s Free Day. The night before we had filled up our shopping carts with $100 worth of electronics (and some sweet t-shirts). I had filled my cart with two XBee Pro 900 RF modules with an antenna, which I have wanted ever since the FunJet UAV has been on the home page of DIY Drones. These modules have a range of up to six miles and would be great for telemetry from an UAV down to a ground station (read: laptop).

We woke up at around 10:15 AM and pointed our browsers to our shopping carts. Thankfully, SparkFun had a live countdown to follow. My dad joined a little later, and Andy and I were giving an almost play by play over Twitter. At exactly 11 AM, all of us and the rest of the Internet hit “Checkout!”

Loading… Timeout. Refresh. Loading… Timeout. Refresh. This went on for almost two hours. My dad couldn’t get registered. Lauren only ever saw her shopping cart. I timed out trying to pay for shipping. And Andy made it to the last page, but then after 1 hour, 44 minutes, and 47 seconds, Free Day ended and none of us got any electronics.

On a more positive note, SparkFun became the #1 Google search term, #sparkfun grew into a top Twitter trend, and their store got some much deserved publicity!

Hallo.

To kick off this blog, here is a photo of one of my current projects: a Multiplex EasyStar R/C aircraft + Google Android developer smart phone = Unmanned Aerial Vehicle (UAV). This photo was taken on a cold, rainy, and windy day in early December at Ft. Benning, GA.

The UAV is remotely operated by a safety pilot on the ground, while the smart phone records sensory information and takes photographs. Below are just a few of the photos captured during one of the test flights at altitudes between 300 and 500 feet above ground level (AGL). By the end of this two semester project, the team plans to demonstrate fully autonomous flight of the UAV.

I develop and implement the flight controls in the autopilot. In the first phase of this project, I ported the ArduPilot to work on the smart phone and its Android platform. The flight controls consist of simple proportional-integral-derivative (PID) controllers, which adjust the elevator, rudder, and throttle. The accelerometer, digital compass, and GPS receiver on the smart phone are used as feedback in the control loops. I plan to explore more complex control strategies in the second phase of this project.

We plan to extensively document our project on flyingandroid.com, including how to hack the serial interface on the G1 and some other creative ways to connect smart phones to servos.