Whilst interested in the restoration of the Scottish Lowland Canals, I noted that at many of the opening events a company called Hawkeye provided unusual photographs from odd angles, mainly from pump-up masts (examples are linked from here). Being a Scotsman I thought, how could I do that - cheaply. So came my first foray into KAP, total cost about $2, plus some scrounging. Read on how you can start experimenting too.

Scrounging round the house got me my son's Air-Craft kite. Single string, parafoil style, about 2ft². 

A little persuasion of a friend and he lent me a AIPTEK Pencam, shown right. I assured him I wouldn't break it. A promise I guess I'd have difficulty keeping! He had limited use for the Pencam because of it's low resolution, 352x288 pixels, and poor sensitivity from it's CMOS detector. However at just under 2oz, with a 80 picture memory, and USB download, it sounded just the thing. Also if I trashed it, it looked like e-bay could conjure up a replacement for about $15.

To get airborne, the limiting factor was a mechanism to press the shutter when the camera was in the air. It needed to be light, simple and cheap, what follows is a description of a modification to the Pencam that adds to it's functionality a 5 second repeated automatic shutter release. With an 80 image memory, that's nearly 7 minutes flying time. As long as you keep taking pictures every 5 seconds the camera doesn't auto shutdown.

Component List
R1    147Kohms
R2    8.25Kohms
C1    47uF tantalum (6 or 10 volts)
C2    0.1uF decoupling
D1    any schottky or germanium diode
U1    CMOS 555 timer

The circuit is a variation on the 555's standard astable operation. R1 charges C1 until pin 6 reaches the threshold point. The  open collector output, pin 7, is at this point used to trigger the camera, and the pin 3 output discharges C1 till pin 2 reaches the trigger point. D1 ensures that when pin 3 goes high again R2 doesn't recharge the capacitor, R1 does this. The cycle repeats. This is an unusual arrangement for a 555 timer, and only works where R2<<R1, however it does leave pin 7 free as our open-collector output to the Pencam. With the values chosen the period is 5 seconds. To a first approximation R1 varies proportionally with the period, but timings over 25 seconds are dangerous as the camera will auto shutdown. There is no reason why this circuit could not be used to trigger any electronic shutter as long as the shutter is activated by shorting a line to ground.

The inside of the Pencam is shown right.

The optical sensor on the left, battery compartment on the right. The black circle in the centre is the beeper. There is a small space in the case between the sensor and the beeper, above the main logic IC.

The additional circuit was built as a tiny rat's-nest, using surface mount components connected to a through hole 555 timer.

The 555 is "legs-up" on the left, the 47uF capacitor is on the right. All other parts are soldered to the underside of the 555 timer.

The additional circuit in situ. A spot of epoxy holds it in place.

The GREEN ground wire is connected directly to the battery negative. The RED supply is connected to the battery positive via a two pin hard drive selector link. One pin is soldered directly to the battery connector. The connector is epoxyed to the case bulkhead and is accessible through a small hole filed in the case beside the USB port. The WHITE wire connects to the non-ground side of the shutter switch (out of shot), the bottom of the picture as you look at it.

The re-assembled camera, showing the two pins sticking out beside the USB, with the link in the foreground. I used a piece of thread to tie the link to the camera so it didn't get lost.

With the link removed the camera works as normal, with the link inserted it takes a picture every 5 seconds.

Normal operation is to switch on the camera and set it up using the mode switch, then insert the link just before take off.

It was attached with a simple 2 cord harness, along the kite line. One of the cords, made of 85% polypropylene thread, is shown on the right. From left to right

• Loop attached to the camera pen clip or battery compartment, a little sticky-tape helps.
• Length adjuster, cut from a plastic pot.
• Miniature clip attaches round a loop in the kite line.
• Paper Clip attaches round kite line as an emergency device

...and here is the result, taken on the 6^th September 2002, during the maiden flight. In lightish winds the kite just managed to lift the 2oz load. 

The picture is the stand of trees round the White Gate entrance to Dundas Castle, South Queensferry, Scotland. The famous Forth Rail Bridge can just be seen top left.

Cairnpapple Hill

The 3^rd January 2003 saw another outing for the Pencam, this time in the Scottish snow.

The images are of Cairnpapple Hill in Central Scotland. This was an important Prehistoric Burial and Ceremonial location between 3000 and 1400 BC. The site is maintained by Historic Scotland.

The image shows the small Nissen Hut visitor Centre left and the main burial mound to the right.

 This vertical shot shows the main cairn and satellite burial chambers and ditches. The original cairn has been replaced by a concrete dome, entered through the smallest of the 3 rectangles on the top, just below the steps. The larger rectangles are 2 windows.

The images were taken using a Sutton Flowform 16 (massively overpowered for the 2-3oz camera rig used - described at the top of this page). Images are a team effort by James Gentles and Peter McCulloch.

PENCAM VGA, June 2003: With the original Pencam returned to it's owner, I purchased another for my own use, despite the low resolution this is a fun addition to the kite bag. This time the Pencam VGA was purchased for $15 on ebay. This model takes either 107 QVGA or 26 VGA images.

This model is more roomy inside than it's predecessor, mainly to make headroom for a standard USB connector. This allowed me to include a small preset to vary the timer from 5 to 20 seconds. I also included an improved switch for enabling the timer.
This shot shows the inside of the Pencam VGA. As before the camera lens is on the left and the battery compartment is on the right. Unlike the last modification the large USB connector means there is no room for the additional circuit between the beeper and the lens, however there is enough headroom for the circuit on top of the beeper.

There is also headroom for the white trimpot at the top of the picture. The 500Kohm trimpot in series with a 100Kohm resistor replaces the original R1, 147Kohms. The detailed image on the right shows a small 3mm hole in the casing which allows the delay to be altered. Note the marks for 5, 10, 15, and 20 seconds.

Finally note the tiny switch (to enable the timer) to the left of the USB port (it has two orange wires to it above). The switch sticks through a small slot cut in the case (as shown in the detailed image on the right) and can be operated with a fingernail when the USB is not connected. The switch was salvaged from an old 256Kbyte memory card, it was the write-protect switch. The switch is marked N for normal and T for Timer operation.

Although giving VGA resolution for less than 3oz, the disadvantage is that this camera only has a 26 picture memory. To get round this I also bought a "Pencam" clone (unbranded) which has the same feature set but includes jpeg compression of the images. I don't recommend this route, the optics are poor, supplied software is a bit tacky, and the internal construction doesn't lend itself to these modifications.

An improved harness was also employed. Thanks to Peter McCulloch for most of the ideas in this area. Although again slightly heavier this reflects the fact that I now have better kites and more room to play with even on calm days. 

This is a fun camera and doesn't warrant a picavet, so I use a simpler 4 cord harness as shown left. 

The harness cord is tied off at one of the fixing points to the line (BLUE), and runs through the other and the grey cross as shown.

The harness is attached to the kite line using a modified cord lock as shown right. The line is pulled through the cord lock and looped round for security. A crochet hoop is used to do this, and also to store the harness so that it doesn't get tangled. The cord lock illustrated has been modified to allow the harness cord to be attached but some cord locks have attachment points built in.

Finally there is a Brooks Horizon Helper^TM  on the end that isn't tied off (shown right).

Finally the camera attached to the harness, with a large rubber band. It can be orientated in any direction using this method.

The Horizon Helper^TM  and the way the cord is passed through the "cross" allows you to deliberately set the camera facing in other angles other than straight down as shown here. Note the loop in the bottom left arm that can be used to force a non-level cross in conjunction with the Horizon Helper^TM

Finally note the hand strap is tied with a "snap" to the harness in case of elastic band failure.

James Gentles July 2003 HOME PAGE KAP HOME PAGE