Aftermath of a Crash: Crashtermath

Well, I thought it would be a good idea to get my Raptor 30 helicopter tuned up and running again. Found a nice guy out at the flying club (www.crskyhawks.org) who got the thing setup correctly. Ended up running three tanks of gas through it while trying to hover, accidently landed with a 'bit' too much left to right 'slide'. Main rotor kissed the ground and a 'pieces-of-helicopter-fountain' materialized.

Upcoming Weekend: Stay Tuned

So, I'm headed back to Old Kinderhook this weekend, and I'm planning on doing a bit more First Person Video if the weather cooperates, so expect more another video post soon afterward. I haven't had much time to do any development due to wedding planning, bachelor partying, float tripping, and wedding attending. I've scoped out a bunch of new places in Cedar Rapids where I'd like to do some 'longer range testing'. We'll see how it goes.

UPDATE:
Unfortunately, I wasn't able to do any flying as we were REALLY busy getting the house ready for the upcoming wedding. We'll see if I can't get some flying done on the Sunday/Monday after the wedding. (October 4th!)

Seeing is Believing: First FPV Flight

I was able to finally get some real first person video (FPV) flying in! I had left my video recorder at home, so I borrowed an Archos 605 Mobile DVR which made a HUGE difference. Much larger screen made it much more comfortable for me to finally take my eyes completely off the airplane. I got about 20 mintues of video flying at Old Kinderhook (golf course in Missouri). Unfortunately there wasn't a good landing point near where I launched from, so the flight ended in a crash! Luckily, the Easystar was fixed in less than 5 minutes with some epoxy. Check out the edited video below!

Development Stalled: Microcontrollers are Hard to Debug with PRINT Statements

I've done a fair about of tinkering with my UAV code the past month or two. I currently am able to read in a current GPS position, specify a 'desired' GPS position, and receive back the bearing and distance to the desired point, from my current point. I have programmed in some 'starter' code in order to have the rudder deflect to attempt to correct the aircraft's course using the actual track of my aircraft and comparing it to the desired track.

So far so good, except I have run into an issue testing the code. Since I only have one UART (serial port), and since I need it for GPS data, I haven't been able to 'debug' and test the code using PRINT statements like I'm used to. For a few weeks I dabbled with adding an LCD screen to printout relavant information, but that also proved to be a huge headache as type conversions, GPS errors, etc all started piling up and I never knew which part of the system was hosed. In order to solve this problem, I am going to implement a 'Software Serial' interface in order to do some real debugging and continue.

In addition to the above issues, I have had spotty luck with the accuracy of my onboard calculations. I'm not sure if the GPS is overoading the buffer, or what the issue is at this point, but I assume the answer will fall out when I am able to debug properly again.

GPS Success: Navigation Data Acquired

After fiddling a bit with the ETEK GPS Receiver, I finally got real data to come out! The datasheet included said the default baud rate was 4800 but it is infact 38400 baud. I assumed 4800 and the data being shown piped from the Arduino was all kinds of garbled nonsense. I decided to bypass the Arduino to see what was actually being sent from the GPS by loading a blank sketch (read: empty program which does nothing) onto the microcontroller. I popped up trusty old Hyper-terminal and started reading the nonsense. After setting the baud rate to 38400, the beautiful NMEA strings were happily populating my terminal window.

Next steps are to decode the stings and assign the outputs to readable variables. Anyone have a GPS output simulator?

Progress Continues: Microcontroller and GPS Purchased

Arduino Diecimilia

Why?

• Has a serial input


• Multiple Analog input/output controls


• Very cheap (~$30)


• Familiar programming language


• Large user help base

After buying this, I realzied I need a GPS first and foremost:

ETEK EB-85A

Why?

• Cheap (~$55) seeing a pattern here?


• 5 Hz refresh rate (say wah!?, most are 1Hz, or even 1/2Hz)


• Serial NMEA output

Anyone know where I can get cheap, accurate pressure sensors?

EasyStar Completed

The EasyStar is finally finshed. I was able to fit all of my 'current' components inside without any issues. There is not a lot of 'extra' room to fit the microcontroller board and wiring internally, so I will more than likely be attaching the electronics to do temperature, pressure, gps, in a separate detachable module. This will allow me to use other aircraft as test beds as well without having to tear apart a perfectly good plane!

Construction Continues: Organizing Internal Components

Here is a closeup of the motor mount (aircraft plywood) which I cut out to support my brushless motor. The original plans called for a brushed Speed 400 motor which was to be glued into the aircraft. Since my brushless motor is an 'Outrunner' (outer part of motor actually turns), I had to mound it to something immobile inside the motor fairing. Luckily, nothing was rubbing when I glued it all together.

One more motor mount closeup

Two halves of the the aircraft just before I glued them together

Here you can see some of the internal components (from front to back):

• The 6-Channel JR Receiver


• 500mW Video Transmitter


• Camera Voltage Regulator

The following items round out the rest of the components:

• Camera Battery


• Flight and Video Transmitter Battery


• Brushless Electronic Speed Controller


• AXI 2212/20 Brushless Motor

A New Beginning: EasyStar Construction Begins

After ordering on Thursday evening, my EasyStar (and accessories) arrived on SATURDAY! I spent a few hours Saturday and a few hours on Sunday getting the thing whipped into shape. The rudder looked awfully inadequate; so instead of proceeding how the kit recommended, I decided to modify the tail to use an aerodynamically balanced (and larger) rudder as you can see in the picture.

I discovered I was short one HS-80 servo for the elevator, so I'll be stopping by the local Hobby Shop to pick that up today.

Platform Selected: Multiplex EasyStar

The decision was between three aircraft; all available from Hobby-Lobby.



1. Multiplex EasyStar

Very affordable ($59)

Probably fits all my current equipment (propeller will most likely be too wide)

Easily upgradable

Spare parts available

2. Hobby-Lobby Wingo

Most expensive of the bunch ($99)

Landing gear

Greatest wing area (for slower flights)

Not as easily modified

3. Graupner UHU

Sort-of Landing Gear

Relatively expensive ($98)

(Honestly, I didn't research this one much)