Lead Author: Mauricio Ayllon Unzueta
The cameras used and installed in the payload are the GoPro HD Hero 960 and the Canon Power shot A2200.
Performance in Cold Temperatures
The GoPro HD Hero 960 is specifically designed to withstand extreme conditions. According to the specifications found in the manual and website, there is a heating system built into it in order to keep the battery warm. Furthermore, the camara is enclosed in a perfectly sealed case that will provide insulation as well as strength. This is necessary since the payload will be exposed to temperatures as low as -60 ̊C. The Hero 960 takes full high definition video at resolutions up to 1280x960 pixels at 30 frames per second. The battery lasts up to 2.5hrs, which is enough for the duration of the intended flight. We will use this camera to take video throughout the whole flight.
The Canon Power shot A2200, on the other hand, cannot withstand harsh conditions as well as the GoPro. Moreover, it is originally set to turn off after some predetermined time, and its battery does not last the two hours needed when running continuously. Therefore, these original setting were changed using a firmware. The firmware used is the CHDK (Cannon Hack Development Kit), which is free software uploaded to the camera’s memory card in order to enhance certain capabilities. More specifically, the UBASIC script was uploaded with the purpose of doing time- lapsed photography and to disable the automatic turn-off. This makes it possible to choose the interval of how many seconds in between pictures being taken. After this first issue was resolved, in order to save battery life, the back LCD screen was disabled. The firmware for our specific camera is still in beta so that function does not work. To get around this, a 3.5mm headphone jack was plugged into the AV ports. In this way, the screen turns off but the camera remains running. This works because the camera “thinks” it is outputting its display to another source. That is how we resolved both issues.
We did not expose the Cannon camera to very low temperatures because the LCD screen might have cracked and any additional last minute changes would not have been possible. This is not a problem since even if the screen gets cracked during flight; all we need is the SD card where the pictures will be stored. For final adjustments, the Cannon will be in the insulated “hot” side of our payload were a small hole was opened for the lens, and the GoPro will be outside of the payload attached to it with screws.
The final step is to make sure the lenses do not get obstructed or fogged. In order to avoid this, we can spray the lenses with RainX and cool them down before launch.