Sunday, November 17, 2013

Film yourself!

Motivation

In preparation for the upcoming Snowboard class for carving, I took the software from the GPS Tracker and tweaked it a bit. Now it works like a remote release and supports two modes

  • Laser light barrier: Whenever anything passes through the camera is turned on for a selected number of seconds
  • GPS fencing: Whenever I am - carrying the GPS receiver - inside a defined area the camera keeps filming/taking pictures
So for the snowboard class I will put the Laser barrier somewhere at the edge of the slope and position the camera to see as much as possible of the snowboarder, without being too small. Given that the remote trigger is sent via XBee, which has a radio range of up to 1000m, I can move the camera multiple times to get different angles.

If I am going for snowboarding for myself, I don't need use the laser, it is enough to base the trigger on the GPS signal. If I am within a certain angle and distance from the camera, then it will be turned on. 

Here is the sequence of images I have just taken.
It was really dark outside already.


Implementation

All of it is based on the OpenPicus Flyport for Wifi. The Flyport provides a Wifi AccessPoint you can connect to and a webserver. Using this webserver you can configure everything, e.g. in GPS mode the area the recording should be kept going, and using the laser barrier the time you allow for the autofocus and how long the recording should take place.
Control Screen


Control screen as shown on the browser

You can also select if the camera is in video or photo mode, because in photo mode the micro controller will keep the shutter pressed the entire time, in video mode the first shutter press is for turning the video on, second press stops the video capture.


The Laser and the remote

The Laser is an industrial device that usually costs around 400.- EUR. Reason is, this is much more than a light sensor plus laser as it would not work outdoors then. In broad sunlight, the light sensor would be maxed out and not recognize the little additional light coming from the laser. Instead it does use modulations, turning the laser on and off at a high frequency. As long as the sensor keeps seeing such modulation it knows the beam is reflected still.

Laser reflector
The stand I milled yesterday - nice, isn't it?

What's nice as well is the speed and reliability of the entire thing, e.g. checkout this picture


The camera setup I will use normally is to position the camera, set the aperture to be hyperfocal or at least cover most of the area without too much distortion and once the image is sharp, turn off the autofocus to avoid losing images because of searching the focal point.

More to come next week, after the snowboard class ;)
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