[8.20.11] SHARK KITE: Kite aerial photography [on the cheap]

A quick adventure in kite aerial photography, built on readily available parts in an afternoon

This project documents the mixing of a cheap craigslist digial camera, a semi-broken atmel dev board and a shark shaped kite to obtain low altitude aerial imagery

What? Components How To Imagery References IMAGE DIRECTORY

What? Image/ Media
Building a lightweight kite imaging platform can be done on the cheap!

The following documents a walk through of a quickly built sequential imaging setup for a low cost camera. The intent of this setup was to complete building and testing in the same day, using readily accessible parts.  The effectiveness of the kite photography system is drastically dependant on  the craft's mass and the prevailing winds.  A lack of wind can be substituted by running about up and down a beach front with kite chasing comrades.

What do I need to make this work Image/ Media Image / Media
Low cost / old digital camera
Camera was purchased off craigslist for 20$, it is a knockoff 'OPTIMUS' camera, apparently sold by radioshack in the early 2000's

The camera functions well, however it  eats its AA batteries rather quickly.  It has no external shutter input, and modifications are necessary to take images on a kite

Microcontroller DEV board / 555 Timer
An Arduino development board was used, found in an unknown state labeled 'bad'

For the purposes of this test flight we could have used a 555 timer and a pile of passives, however this was far more convenient 

KITE [AMAZON] A Large kite was chosen for the test flight, to lift the camera payload. There are a number of varieties available, generally a local corner store has them hidden somewhere.
Battery Pack (preferably lipo) A lightweight cell-phone lipo bag cell was used to power the imaging electronics. The lipo was fed directly to the 5v rail. The atmega168 has an operating range from 2.8 -> 5.5v, so it was well within the operating voltage of the IC

How to:   Image/ Media
Open it up
The camera in this project did not have an external shutter trigger, so a more 'direct' approach was used. After removing the batteries, the external housing was carefully opened, and the screws / fasteners were placed on a tray to prevent loosing them.

Examine the shutter button
The camera was torn down  to reveal the membrane pushbutton to enable the shutter. There are 4 contact points for this button and they connect in 2 stages. The left 2 pads connect when the button is slightly pressed, to inform the camera to begin focusing, and the right two pads connect when the button is fully engaged, triggering the camera to take a picture. This was determined by first using a multimeter to determine if a potential was available across the pads, and then observing how that potential changed as the button was pressed. You will look for a voltage delta (~3v) changing to 0V when the button is pressed. Connect 2 wires to the pads that present this characteristic
Carefully solder wires to the trigger pads

Verify that the selected wires trigger the cameras shutter by carefully powering up the camera and connecting the two wires selected from the previous step, observe that the camera does take an image.
Tying to a microcontroller / timer.

The I/O lines on the micro  in question (atmega168) can source and sink 15 mil-amperes, we were able to take advantage of this and have an IO line  'ground' out the trigger line, causing the camera to take an image. The worst case image-taking time was recorded as slightly over 3 seconds. A delay loop, listed below, was used to trigger the camera to take an image every 5 seconds. The camera and microcontroller setup now will take an image every 5 seconds until the cameras memory card is full.
Admittedly, the arduino is overkill and a half, however it was mighty convienent.
An astable oscillator with a 5 second time constant could have sufficed
Tying Everything up and sealing the camera

The two trigger button was removed (plastic insert) and the two IO lines were routed out of the camera. As this was a low cost camera that lended itself to be modified, these are semi-perminant modifications, and as such its easier to select a used beaten up camera that has a defect, versus an expensive state of the art canon / leica
Constructing the camera-holder

After the camera & controller are tied together, building a 'holster' on the kite begins.
The desired size would hold the camera in place, but allow it to be removable in case of 'field debugging'

Sewed-on camera holster

Using ninja sewing skills, the camera holster was sewed together. The advantage of sewing on the holster directly to the kite is twofold.
It provides a very effective distribution of mass while also being extremely lightweight.
A plastic insert was glued to the front of the fabric to reinforce around the area where the camera lens leaves the holster.


After a quick verification that the camera was indeed taking images once every 5 seconds (listening to auidable click of the shutter), the SHARK KITE was launched
Get it to FLY

Run around with kite flying comrade and attempt to take high altitude imagery!


(There's other photos in the photo gallery)
Concluding Remarks:
Mass of the craft and wind speed are crucial to the effectiveness of the craft. Initial testing with a dummy mass was helpful in determining the optimal positioning of the camera subsystem. If this project were to be reconstructed, a lighter camera, possibly with a waterproof housing would be chosen. A number of canon cameras are supported by chdk which allows for a firmware upload that preforms the sequential imaging without the need for an external trigger.


Wikipedia: Kite Aerial Photography  [http://en.wikipedia.org/wiki/Kite_aerial_photography]

Testing with Video
A small video camera was also tested on this kite, this [link] camera was used. Note that the kite platform bounces around and jiters back and forth, resulting in some fairly bouncy video. The camera used is extremely lightweight, running from a tiny internal LiPo module and storing data on a micro-sd card. Note that this version of the camera had a noticeable rolling shutter [link]     The view from that height is excellent!

Who made this project? 
Dane Kouttron Emily Krupczak

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(be careful, im not responsible for your exploded battery pack / submerged camera )

Rensselaer Polytechnic Institute 
Electrical & Electrical Power