Assignment 3: Testing for Aerial Mapping

Introduction

This exercise was to help us to prepare and experiment for two of our upcoming activities.  We will be making an aerial map of our campus using a weather balloon and a camera. The other activity is sending another balloon into space and videotaping its flight. We will have a tracker installed with the camera so we can find it after it lands.  However that’s in the future. First we needed to do research and some experimentation to get our rigs ready for the launch. There was a list of things that needed to be down. We all split into teams to work on a separate task. The tasks were constructing the mapping rig and high altitude balloon launch rig (HABL), the parachute needed testing, needed the payload for each rig, figure out how to work the continuous shot for the cameras and how to make sure they did so on the rig, testing the tracking device and figuring out how to fill the balloons and securing them to the rig.  We were encouraged to move between groups so more ideas could be discussed. I mainly worked with the group who was making the mapping rig.  

Methods

Before we started making the rigs, we first had to figure out how to get camera to take continuous pictures. There were three different cameras that we could use and each one had the continuous mode hidden in a different spot.  Once we found the modes, a few people split up to figure how to keep the camera shooting without a person holding down the button.

For instructions on building a mapping rig we were given instructions that were provided with the kit we bought. The materials that we were given was just a collection of random objects our teacher, Joe, thought we would need. Figure 1 shows several of us trying to decipher the instruction that were provided. The problem was that the instructions were basically pictures with very little words describing what to actually do. Click here to see the instructions that we used to help us build the mapping rig. The instructions told us to use a soda 2 liter bottle (Figure 2). It told us to split the bottle in half and use the top half to hold the camera. 

Figure 1: This shows several students looking at the paper instructions on how to build and aerial rig.

Figure 2: This is a picture of a soda bottle like the one we first tried to use for our rig

However we soon found out that this would not work. The cameras that we will be using are two big to fit inside the bottle. Figure 3 shows our group attempting to get the camera into the bottle. Once we could get the camera into the bottle, the bottle was completely deformed and would not suit our needs. At this point our group broke up into two different directions. One group decided to keep trying to make the soda bottles work. Instead of cutting the bottle in half, they decided to flip the bottle horizontally and cut open a hole so they can get the camera in. This rig was duped the Hindenburg.  The other group decided to go in a different direction.

Figure 3: This pictures shows Amy putting the camera into the soda bottle. It also shows Joe, Kent, and Bia looking at the continuous mode of one of the cameras.

We decided to totally forget the about using soda bottles and instead used a cleaning solution bottle that Joe brought in. Figure 4 shows me and Bia getting ready to cut the new bottle in half. As you can see the cleaning solution bottle is much wider than the soda bottle. This allowed our camera to float around in the bottle like it was supposed to. Figure 5 shows the bottle after it was cut.  Now that we had the bottle figured out, we had to work on using the rope to keep the camera in the bottle. 

Figure 4: This picture shows Amy and Bia cutting the cleaning solution bottle in half to build their new rig.

Figure 5: This is the bottle after it has been cut in two.

The instructions suggested using a meter length of rope to use, but this ended up being too short. We found out that using 2.5 meters was long enough for us but the length of rope would change depending on the bottle your using and the camera. Getting the rope on the camera so it could dangle was a little difficult. The first thing was that we had to make sure that the shutter was not covered so the camera could take pictures. The other important factor was making sure the camera was secure and would not fall out. So we first cut our length of rope and tied the two ends together.  Then we pinched it in half so that there were two loops at the end that would help cradle the camera. Figuring that out was not very hard but getting the rope so it would not cover the shutter was a little difficult because our camera’s shutter went all the way to the edge and left no room for the rope. It was decided to loop the rope around the shutter, the shutter was sticking out a bit, and tape it up that way. Figures 6-8 show our final construction of tying the rope to the camera. 

Figure 6: This is the front of our camera withe the rope taped on. It also has the first trigger we built for holding down the button. This trigger is the orange rubber band.

Figure 7: This is how our camera will hang inside the bottle. It will hang upside down just short of the lip of the bottle. Again the orange rubber band is our first attempt of a trigger.

Figure 8: This is what the camera looks like when looking down at it.

Once you have the camera attached to the rope you then put it in the bottle. Pull the rope up through the bottom and out of the top. The camera should be hanging just shy of the edge of the bottle. Say 2 or 3 cm at most. You don’t want the camera to close to the edge because then the camera will not have a clear shot of the ground. Make sure to tie another knot at the top of the rope so that there is a loop at the top. This loop will be used to secure the rig to the balloon.

The next step was getting the camera to take pictures without anyone holding down the button. Bia and others came up with the idea of cutting an eraser down a bit to use as the trigger. They decided to use a rubber band to hold down the eraser so the camera would take the pictures. If you look back at Figure 1 it shows Bia working on getting the trigger to work in the bottom left hand corner. Figure 9a shows a camera with the rubber band and eraser on it. Officially this did work, just not as well as they had hoped.  The problem was getting the eraser under the rubber band. It was quite difficult to get the eraser under the rubber band because it was so tight, but any looser and the rubber band wouldn’t hold down the eraser. When we finally got the eraser in place it would not always work. It would probably work every one out of four times. So instead we came up with the idea of using a larger rubber band and tying a knot in it. This knot would be used as the trigger instead of the eraser.  

Figure 10 shows our rubber band. We tied a knot about a third of the way down. Then taking we would loop the smaller of the loops around the camera first with the knot directly over the button. Then you would take the larger loop and loop it tightly over the knot. Figure 11 demonstrates the final trigger design. 

Figure 9a: This shows our first trigger. It uses a piece of eraser like the one shown below in Figure 9b. A rubber band is fastened around it and the camera so that the button is pushed to take a picture.

Figure 10: This is the rubber band that we will be using as our trigger. It has a knot tied in it about 1/3 of the way down it.

Figure 11: This is our camera with the final trigger in place. We first put the small loop around the camera with the knot over the button. Then take the larger loop and put loop it around the camera over the knot till it is tight and the camera is taking pictures.

After getting the camera and trigger ready to go, we had to finish with our bottle. We had to put some wings on it so the bottle would not spin in the air. The instructions told us to use the remaining half of the soda bottle to make the wings. The lower half of the bottle was not long enough to cut our flaps for our wings, so instead we used an uncut bottle. The instructions suggested using  20cm long and 6cm wide flaps. We were to position them on the bottle angled at a 30 degree angle. We used the measurements provided for us. Figure 12-13 shows our bottle with its wings on it. 

Figure 12: This is our bottle with its wings.

Figure 13: This is our bottle with its wings from a side view.

The instructions said to add another loop of rope to add more security for our camera. You tie a knot in the middle of the rope holding the camera. Loop the second rope through the opening between the camera and knot and thread it up through the opening of the bottle. Secure the end of the rope to a flap at the bottom of the bottle. Figure 14 shows this second loop. 

Figure 14: Rig with the final rope attaching the camera to the bottle.

Our rig is set to be hooked up to the balloon and take aerial pictures of our campus. Using these pictures we can mosaic them together to get a large aerial photo of our campus. This will be interesting because in the last two years we have built a new Student building, demolishing the old and is in the process of building a new education building. Figure 15-16 shows our final rig.

Figure 15: This is our final rig looking at it from the side. It does have the camera inside, you just can't see it very well

Figure 16: This is our final rig looking up at it. It shows our camera being suspended freely inside the bottle.

We will also be sending up anther mapping rig called the Hindenburg. This group used a soda bottle to make the platform. Instead of cutting it in half, they turned it sideways and cut a hole in the side for the camera. Instead of rope to secure the camera, they used zip ties. They also used zip ties to form loops at each end of the bottle so that a rope could be tied there. This rope would then be secured to the balloon.  Figure 17 shows this group cutting a slit in the bottle so that they can insert the zip tie. The Hindenburg has its wings at one end of the bottle. Figure 18 shows these flaps being added on. Figure 19 is a picture of the final construction of the Hindenburg.

Figure 17: The Hindenburg getting its zip ties for the rope

Figure 18: The wings are being added to the Hindenburg

Figure 19: The final design of the Hindenburg.

The video below shows some students testing out the parachute. The bucket has a simulated weight of what it should weigh for the real launch. They dropped the bucket out of a window and let it fall to the ground to make sure the parachute could slow down the weight.

Another group weighed out all the items we would be putting on the HABL. We need these weights to know how large the balloon needs to be. 

Figure 20: Students weighing out the pay load.

Discussion

It took us some time to figure out the continuous mode for each of the cameras. They were each a different kind of camera and had no instructions on how to find them. We eventually found the mode for each camera but it took a while.

 Another problem we ran into was with the instructions themselves. They were very unhelpful. While there were some pictures, these pictures were all in cartoon form and only moderately helpful. Then the words themselves describing the pictures were usually one sentence long and not at all helpful. So as a group we had to fill in the gaps and come up with ways of getting our rig working. This exercises emphasized the importance of working as team to get the job done.

We also ran into a problem with getting a functioning trigger that was easy to use and was reliable every time. The first idea of using an eraser and a rubber band was a good one and in the end it did work to a certain point. But it was not at all easy to use and not very reliable. So after putting our heads together we came up with another idea of using a larger rubber band with a knot tied in it. This idea turned out to be easy to use and quite reliable. This problem taught us if you first don’t succeed try, try again.

One of the main problems we came across in this activity was the lack of good tape. Joe provided us with all the materials he thought we would need. Unfortunately he forgot good tape. He did have some packing tape but it was not very sticky and will not be used for the actual launch. The tape was good enough for use in experimentation though. It was difficult to get our camera attached to the ropes securely. If we bounced the camera around too much the tape would fall off and down goes the camera. For the real launch we will be using much stronger tape like duct tape.

Results

We did all this prep work so that on the day of the launch we will have everything ready to go. There most likely will be some problems that arise but they will be minimized by the fact that we did all this testing beforehand.