GigaPi Project
by Tim & Jack Stocker
Objective:
To build an automated panoramic tripod head for use in photography, the main
purpose to accurately produce an image using many/hundreds of separate
photographs, enabling very high detail and the ability to zoom in on minute
details.
Components:
After some research we decided to build our GigaPi using the following:-
Main camera support/gimbal: MDF frame, providing controlled tilt around
the camera nodal ( no parallax) point. Lego Turntables
to provide the pivot points and gearing.
Tripod Head/Pan
control: Cheap laser level kit (Tribrach), Modified with a worm and gear
drive.
Camera/Mount: MDF
frame designed around a Canon 5DMKII, and a adapter plate top allow Lumix FZ100
to also be fitted. 'Fotomate' Focus Rail fitted to allow the no parallax point to be set for each
camera and lens combination, connected to the frame using a bolt.
Drive: Two 5volt DC Stepper Motors, one for panning
and the other for tilting, with worm drive gears
fitted.
Control:
Raspberry Pi to provide the computer control, including pan, tilt, shutter
operation etc. Stepper motor
driver circuit board attached directly to the Pi and shutter control circuit designed and built by us to
operate the shutter electrically. Modified remote release cables for both cameras to enable easy
connection to the board via a 3.5mm jack plug. USB hub connected to the Pi, to enable connection of a keyboard,
memory stick etc. A rechargeable battery
pack to be used to power the PI.
User interface: A 12 volt 5 inch display screen (actually a
car reversing camera display) and a touch pad
to provide the interface. All housed in
a project/instrument box, with outlets for
shutter, stepper motors, USB and charging point.
Software: Bespoke programme written by Jack to control
every aspect of the operation of the GigaPi. The programme is
required to calculate the horizontal and vertical angles required, the camera sensor size, the length of zoom used
and the image overlap required, it then needs
to calculate the total photos required to complete the task, operating the
stepper motors the required amount in
the right order and fire the shutter at the right time, allowing for focus and shutter activation time etc, a
tall order indeed.
Build details:
One inch thick MDF cut with a jigsaw and filed and sanded to
a smooth finish, two lego turntables fitted to allow it to tilt, the pan/pivot
point is set to the center of the camera lens.
A cheap 5volt DC stepper motor was fitted with a worm drive
to turn the 56 tooth lego gear, an MDF block made to provide the correct
spacing for the gears.
A cheap laser level kit brought off the internet provides
the panning control, even comes with a tripod for around £20. the three plastic
screw adjusters were removed as they had too much side play in them, replaced
them nuts and bolts. A 40 tooth drive gear fitted on the center bolt which had
to be modified to provide a 4mm shaft for the gear to fit onto. Another 5v
stepper motor fitted to a hand made bracket and a worm drive gear press fitted
to the shaft. Both motor wires were then fitted with an RJ45 jack plug to
enable quick connection to the control box later on.
The completed framework was painted yellow to match the
laser head, and a focus rail bolted into place to allow the nodal point of the
camera lens to be set.
Raspberry Pi computer, you can also see attached the Stepper
motor driver circuit, and two RJ45 sockets to allow easy connection to the two
stepper motors, you can also see in the bottom right hand corner 4 wires
soldered on to the back of the stepper motor board to provide the power, earth
and activation of the focus and shutter
control relays.
This is the shutter control circuit, designed by us and laid
out on Vero board. it's is basically two 5v solid state relays which are
activated and powered by the Pi. One controls the focus/exposure function, and
the other controls the shutter. The relays close the circuit on the shutter
release cables, starting with the focus/exposure function and this remains on
whilst the shutter is activated a split second later.
This is the completed circuitry. The Raspberry Pi at the
top, the stepper motor driver circuit fitted, the shutter activation on the
right, the USB hub on the left and the touch pad and display screen.
The project/instrument box, was cut to allow fitment of all
the components, plus the Anker Astro 3
rechargeable battery pack. A hole was made in the bottom of the box to allow
access to the power button, and an on/off switch fitted to the front panel to
allow the screen to be powered on and off.
The battery pack provides enough power for several hours
work, provides both 5volt for the PI/stepper motors, and 12volts for the
display screen.
This is the completed
setup. It is fully portable and all the control cables can be unplugged easily.
LINKS:
The bespoke Raspberry Pi programme code: https://github.com/Frankincense/GigaPi
Stepper motor: http://www.ebay.co.uk/itm/290850433156?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
Stepper motor C code: http://unicorn.drogon.net/step.c
GPIO Stepper motor: http://www.raspberrypi.org/phpBB3/viewtopic.php?f=32&t=10483
Auto login scripts: http://www.raspberrypi.org/phpBB3/viewtopic.php?f=5&t=5225
GigaPi
Panorama Calculator:http://photos.yves.over-blog.com/article-panorama-calculator-mise-a-jour-61831164.html
GigaPan Images: http://www.gigapan.com/gigapans?query=timstocker
