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Thursday, April 2, 2015

Drone Recovery Parachute

Failure is a concern that is always present in the operation of a drone. Given the continued increase in acquisition and use of these devices by the general public, safety is of paramount importance. Even the smaller devices of about 2 kg of total weight, in case of total failure at altitude, will fall like a brick and cause damage to whatever is below.

Most configurations such as quadcopters, don't offer any intrinsic redundancy (in spite of having 4 motors). The failure of a single motor will prevent the quadcopter of maintaining level and yaw-locked flight. Some enhanced control algorithms are being developed to provide level and controlled descent in case of single motor failure. Naturally, yaw control is lost, but the on-board inertial sensors and magnetometer are capable of keeping track of the orientation, therefore knowing how to distribute throttle by the surviving motors.

Monday, March 30, 2015

More UV light photography

It is interesting to discover in everyday objects, the specific fluorescence of each one. The particular wavelength (i.e. color) of visible light which is irradiated depends on the characteristics of the substance illuminated by the ultraviolet light. As such a very interesting combination of colors can occur, depending on the varieties of materials the object has. The following dolls is an example:


Sunday, March 29, 2015

UV Photography

Exploring light wavelengths beyond what our eyes can see constitutes an interesting domain, because in a scientific perspective it can reveal characteristics of the imaged objects, that our eyes and/or visible light based cameras cannot see.

For example UV photography can reveal the story of our skin. Solar UV burns leave scars that are practically invisible to the naked eye, but through long wave ultraviolet these are clearly distinguishable from untouched skin (for example see http://www.huffingtonpost.com/2012/06/22/cara-phillips-ultraviolet-beauties_n_1606131.html)

While not having specialized gear for UV photography I decided to give it a try with a UV power LED that I had laying around:


Saturday, March 28, 2015

Custom Camera for Image Stacking

On the expectation of obtaining different and better astronomical images I have taken the oportunity to build custom gear for that purpose. The camera itself is an analog Sony CCD HAD 700 TVL based on the Effio chipset. I had it in my quadcopter, and decided to transplant it to this application. It has excelent low light sensitivity (indeed it outperforms the human eye in that respect!), being an interesting candidate for astrophotography.

My task was to adapt an aluminium enclosure to contain the camera sensor and the control keypad: