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.

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.

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.

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.

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:

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.

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.