Thursday, July 26, 2012

The Polystyrene Cutter

Having been refered to in this post, a very important tool for easy cutting of the bare polystyrene boards was custom built because of saving some money.

While these can be found on the market, good models with adjustable heat may cost over 30 euros. By analysing the kind of hardware I would need, I found that it wouldn't be such a big problem because I already had most of the stuff in my electronics scrap containers.

The only thing I didn't had laying around was the support for the hot wire, which I had to buy. I just used a metal support with a wooden holder for a conventional saw, which proved to serve the purpose just fine:

Thursday, June 28, 2012

Letting it hover...

While the building phase can be an enjoyable experience, grabbing the sticks, putting the chopper on the ground, and gently increasing the thrust until that custom build apparatus starts to appear light on its stands is where the real fun begins. Would we ignore the noise of the struggling motors, and this styrofoam-shielded quadcopter would seem like a magical object for which gravity would be opening an exception everytime we wanted to. There is no magic, just technology, but still there is a sense of victory in tricking gravity in a brute force manner. Not in a magnificent scale as Howard Hughes H-4 Hercules, or lighter than air as Bartolomeu de Gusmão's flying bird, but still admirable for mimicking birds in the size and ability to fly (in a cumbersome way however), and for hovering like few of these animals can.

Monday, June 25, 2012

Multicopter Madness

R/C airplane modelling exists for several decades, but with late improvements and reduced cost in microelectronics, energy storage, and RF communications, products in this domain have suffered a significant improvement in quality and innovation.

Sunday, April 1, 2012

Sensing the Heart Beat

Among the most basic forms of biometric data we may collect from ourselves is the heart beat.Wether to control our body response to sports activities, keep track of our health or to observe involuntary response to external interaction, this is one of the important parameters that is collected by physicians, and specialists of a multitude of health-related areas. What I am describing in this post is just the implementation of one of simplest forms of obtaining a waveform that represents the heart beat of an individual.

Tuesday, March 27, 2012

New layout

After way too much time with the same layout, finally and in sync with Blogger restructuring and connection to Google+, I present you with a bit of a nicer look, which is at least is clearer for reading. Stay tuned, as some new posts are on the pipe, with updates on various topics, such as:
  • Geiger Counter - full schematics and firmware source code will soon be posted;
  • Time Lapse Photography - some new scenes of nature at its best will soon be made available.

Saturday, March 24, 2012

Simulation mode for the Geiger Counter

While obtaining samples of materials radioactive above background is not an easy task (fortunately for the sake of human health), I had to find a way of testing the dose measurement algorithm in a different way. As I have explained in a previous post, the device is divided in two modules: a UI module, and the detector device. Each has its own digital logic, and communicate with each other through an I2C bus. As such creating a simulation mode would be a simple mather of programming a new function in the detector that would allow randomly spaced pulses to be generated, instead of being triggered by the Geiger tube. This have been done simply by using the Atmel standard libraries random() function. Using the interrupt generated by the watchdog timer overflow, the following code is executed periodically:

Saturday, March 10, 2012

More in Time Lapse

And to add to the party, another bit of playing around with time lapse. This time zoomed in on the Tagus river, and obtained this interesting sequence. To achieve it, the intervalometer was set to take a picture every 10 seconds. Again, automatic settings such as ISO sensitivity and aperture were chosen. Only the focusing was kept manual.

Sunday, March 4, 2012

The timelapse intervalometer - the technology behind the device

With the results having been posted in a previous post, it is now time to flesh through the details that led to the creation of this simple yet useful device.

I started with the optimism that my Fujifilm S9600 camera would have some form of remote control possibillity other than the mechanical shutter release that is supported in the shutter button itself.

Saturday, February 25, 2012

Time lapse shooting - moving into more professional results...

While the first videos seemed pretty cool in spite its mediocre quality (maybe because of the time domain wonder of perceiving things that we normally wouldn't given the different time scale we live in), now I had to move one step further.

The idea was to use a better camera, one offering photographic quality in every single frame.

Friday, January 27, 2012

From morning until dawn - and entire day described in seconds

Time lapse video sequences can render exciting results, for the visual impact these provide. While simply being a sequence of frames more separated in time than in a conventional video, once played back at the rate the human vision considers smooth (30 frames per second) these provide a view of the world that a human cannot easily perceive directly, given the comparatively fast rate at which he summarizes and retains information. For instance a cloud in its pass has very complex yet slow changes in shape and trajectory. These are very hard for average humans to perceive, memorize and mentally reconstruct as an animated sequence of events. In general, slow changing processes are inherently hard for humans to characterize in its dynamic nature.

As such it is not surprising that a video containing nothing more than a reproduction of the real world can be appreciated by humans as being somewhat surreal, when simply the only difference is the rate at which information is sampled and later reproduced.

The first video contains about 20 hours of footage shrunk to 32 seconds. It reveals one angle of the Almada city at the south of Lisbon, where part of the 25 de Abril bridge and the Cristo Rei can be seen. It is a typical winter day in Portugal, where the fog floods the morning and a passing of dense clouds fulfills the entire afternoon. This typical day is however solitary in a atypical winter month padded with bright sunny days and mild temperatures.

The second video taken during the 27th January 2012, reveals a clear night transition to a bright winter day in the city of Almada, just south of Lisbon the capital city of Portugal. At the bottom right, the horizon is cut by a huge rectangular crane belonging to a long time decomissioned shipyard.Its name was Lisnave and would once be an important maritime reference for large ships and oil rigs which would stop by for major repairing and overhauling.