Each flight log entry usually represents a launch or test day, and describes the events that took place.
Click on an image to view a larger image, and click the browser's BACK button to return back to the page.

Date:  10th July 2011 8:30am - 9:40am
Location: Doonside, NSW, Australia
Conditions:  Blue skies, 40km/h wind, temp ~12C
Team Members at Event: PK, Paul K, John K, and GK

Pan Cam

Last week I watched a couple of pyro rocket videos of the LDRS29 launch from the US, and saw a very unique shot of a rocket flying past a camera at the top of the tower and the camera tracking it as it went past. So we thought we would give it a go too. Tracking it optically or thermally would have been difficult, so we opted for setting up the camera so it would just move according to a predicted path of the rocket. Knowing the rate of the servo movement, the acceleration profile of the rocket and a bit of trigonometry, we worked out roughly where the camera needed to be.

The original concept of the panning camera for a water rocket triggered by launch was first developed by wyldbytes. He presents his idea here: http://www.wyldbytes.co.uk/?p=225 as a part of an automated and servo controlled launch trigger. A video demonstrating the concept is here: http://youtu.be/F284FmfZuMI

We mounted the servo timer II, battery and an RC servo in a box and put it on top of a tripod. We also attached a bracket to the servo horn so we could attach the Casio high-speed camera to it. The start and end servo positions were configured so that the camera would start out pointing at the nozzle and end up pointing about 85 degrees from the vertical as the last position. We ran a pair of wires from the STII's external trigger to a micro-switch mounted under the rocket's fin. This ensures the camera only starts panning once the rocket actually starts moving. This made it a lot easier to synchronise as rockets can be quite unpredictable as to when they actually start moving when you pull the string.

Launch Day Report

We arrived at Doonside at 8:30am, but the wind was really starting to pick up. Pyro rocket launches were cancelled for the day and so we decided to downsize one of the rockets to just over 3 liters to stop it going too far since we were really only interested in trying out the Pan Cam.

We set up the Pan Cam fairly close to the rocket and launched it at 100psi. The first part of the flight was good but the camera just missed the rocket as it was leaving the launch rail, but caught up with it quickly again. After the parachute opened the rocket drifted a long way down range in the strong wind.

For the second launch we put the camera back about 1 foot, and adjusted the start position to have the nozzle nearer to the bottom of the frame rather than at the center. This time the camera followed the rocket well and the video turned out great. :)

While setting up for the third launch we again pressurised the rocket slightly to make sure it was popped up in the launcher so we could set the microswitch properly under the fin. As I was pushing the switch up to the fin I accidentally pulled on the release mechanism and launched the rocket. Because there was very little pressure in the rocket, it didn't go very high, but since the timer was still turned off the rocket just came down nose first in the grass. The nose fairing was bent, so we swapped the nosecone and reloaded the rocket onto the pad. Other than the bent fairing nothing else was damaged.

The third flight was similar to the second one and the camera again tracked the rocket really well. With the wind speed increasing we packed up and were heading home before 10am.

Overall we were really happy with the results, but didn't get to test it with pyro rockets like we wanted to. We'll try that during the next launch. If I get time I'll have a look at updating the firmware by the next launch so you will be able to set a particular pan velocity profile for the Pan Cam so it will be easier to match a rocket's expected flight profile.

Here is a video from the day including an explanation of how it works and videos from it.

Flight Details