Home Built Hovercraft

While not being the most efficient means of transportation, hovercrafts impress by the ability to operate both in land and water.The inherent maneuverability is also an interesting characteristic. While the driving is entirely different from a vehicle with wheels, hovercrafts are able to change direction very quickly, given the fast rudder response (usually located in the rear, and close to the propulsion source).

Remote controlled flight

In my adventurous quest at being able to fly with my feet on the ground, I begin to understand the true fun of this hobby and how it stimulates the mind to understand the physics behind flight, and in the particular case of the helicopter how stable hovering and forward flight is possible.

Getting airborne (on a scale sort of way)

The ability to fly have been a long envied feature of birds. Since the early days of the history of mankind, there have been the ambition to fly like a bird. The same way the conquest for new lands and the seas have been seeked and achieved by people (both for political reasons and for the bare survival), the skies have also been one of the goals of humanity. While many have envisioned and prototyped flying machines (going back to the time of Leonardo Da Vinci), only during the the 20'th century this dream was fully achieved, with the Wright Brothers having created in 1903 the first controlled powered flight. The war effort strongly stimulated the development of this new, efficient way for people to move, control, watch and dominate the territories.

Carjacking - shortening the path for justice

As automobiles become more sophisticated, direct theft by tampering with the ignition system becomes a nearly impossible task. This narrows down the choices left for the criminals, who end up adopting the only choice where successful access to the vehicle is guaranteed: threatening the occupant(s) with a weapon in exchange for the car.

In general the criminals can get away with this type of crime if they are efficient and careful, leaving the victim with few evidence to help in the investigation and tracking of the vehicle.

However, once again we can put technology on our side, and in an attempt to be resourceful enough, take advantage of two broadly available devices: a cell phone and a GPS module. These devices
are becoming cheap enough to have dedicated in a discrete location inside the car for a single purpose: on demand location.

By being able to query the location of the car just by sending an SMS message to it and get a reply with the corresponding GPS coordinates, this could be a useful tool in the police work, as real time location would always be possible.

Following this idea, I've decided to attempt a simple implementation of one such system which I have designated "Vechicle Finder". Having as a platform a Nokia smartphone and a Bluetooth GPS device (both sitting on a board for convenient fixation of the apparatus), I have developed a Java application which reads the GPS coordinates and sends it as an SMS to the originator of the request SMS:



Upon receiving an SMS containing a special command and some optional parameters, this onboard device will reply with another SMS containing the following data:

The meanders of OBD-II protocols

As we travel through the history of automotive technology back and forth, we realize that at the heart of the machines that enable us to go from point A to point B faster than our legs, are a number of components that essentially haven't changed too much: engines still burn fossil fuels and the vast majority are based on pistons that transform the explosive energy of the fuel combustion into movement.

Decoding ACARS transmissions

Just as with other radio related hobbies, this is quite an interesting one:

Long-haul WiFi - new developments

Returning to the WiFi topic, here is the new antenna development that I had promissed in the early post, once the dual "cantenna" design was finished.

The dual cantenna is quite efficient, as I realized by connecting it to reasonably distant access points (in excess of 200 meters, with many obstacles between, including houses). By verifying the antenna efficiency was the expected, I assumed that in better conditions the range could be far greater, by establishing a link between two antennas of this type or other type of optimal configurations.

However, I knew I could push it a little further, so I decided to buy a 12 euro 45 cm dish from a regular satellite TV system, and the materials to build a biquad feed. I installed the dish on top of the tripod used for the cantennas, and attached the biquad feed (built according to these instructions) to it: