Inspired
by the dropping costs of video camera technology, one intrepid
member of
the Web Wombat team has taken to mounting a You-Tube compatible video
camera in his bike. Take a look at the pics from the video:
Attacking the C-grade
bunch!!
Garbage
truck forces 40k riders into RHL. Cars move into oncoming traffic lane
-
6am Beach Road ride. Good driving! Things were tight and no warning.
Judging
by the interest created
by this simple camera, our Wombat Cyclist has shared the technical ins
and outs of exactly how you can build your very own WombatCam and where
to obtain the parts and their cost. A full inventory of parts is shown
in the right hand panel.
How cheap can a CamCorder get?
Amazingly
enough the
price
of a video camera recorder has plummeted to an astoundingly low level.
You
can get
your own 320x240 pixel (QVGA) camcorder by
performing a search for "camcorder" on eBay. The cheapest unit at the
time of
writing is sub $50 Australian.
After pondering the
possibility of creating race-day cycling videos for a week or two, the
bid was placed! The project was born.
Research on the
web produces an incredible array web pages showing all manner of very
costly camcorders. These are attached to all sorts of jigs mounted to
various bicycle parts and in one case even on a bicycle trailer.
Fortunately,
the Chinese-made camcorder (based on the Sunplus Technology SPCA533A
IC)
used here has no moving parts.
All video is stored on an SD flash card (limited to 1G max - cost $17
at www.msy.com.au). No
moving parts makes for a vibration resistant solution which is a must
for
bike use. Racing bikes, in particular, run on very high pressure tyres
(145 psi in this case) and have no
suspension other than flexing of the carbon fibre frame
components.
Experience from WombatCam's first
outing reveals that a recording of more than one hour of exciting CCCC
criterium racing (only C-grade so don't get too excited)
produces a 390Mb
file. Sunplus have certainly done their homework on video
compression.
More than 2 hours of racing can be crammed into this tiny handlebar
mounted unit.
Editing the resulting file proved to be
challenge as the file format (Microsoft .avi format) used the
new Motion JPEG or mjpeg codec (different from mpeg). Most flavours of
Windows can play the video directly though, as can Linux. However, most
current video editing software will send the would-be director
scurrying to
the search engine to find that new encoder.
Sound
recorded by WombatCam
is completely useless however. All you get to hear are
the wheel bearings, road noise, and the freewheel hub sounds which are
transmitted up through the frame and occasionally broken up by the
Shimano
DuraAce shifters changing gears. Even those loud
uncontrolled outbursts other
cyclists are prone to only barely register.
Would a
professional
cyclist consider this? Well the camera weighs in at 135 grams!!
(without batteries.) Look carbon Keo pedals weigh in at 115 grams each.
So, perhaps.
Mountings
Mounting
the camcorder turned out to be far simpler than anticipated. In a
remarkable stoke of luck, it turns out that the Chinese
manufacturer provided
for a tripod bolt mount on the base of the camera.
In
a further stoke of luck, your Wombat Team Cyclist discovered
that the type of bolt used on a standard tripod is
coincidentally within half a millimeter of the bolt used to
secure an aftermarket mud-guard. It
just turns out that the seatpost and the handlebars are similar in
diameter and both are carbon fibre making this a perfect
solution.
Simply unbolting the guard and
using
the mount together with a 1/4 inch tripod bolt produces a very solid
professional looking camera mount. A slight reaming of the bolt hole
with 6.5mm drill produces a perfect fit.
Supplied by Bentleigh
Bicycles
this mudguard has two "elbows" with knurled knobs. With a bit of filing
it is possible to get the camera bolt hex head to sit neatly into the
original plastic knob recess making for an even more professional
finish.
Stopping the camera from
rotating on the plastic mount was overcome by using a pair of thick
rubber dunny
washers. These grip the bottom of the camera and also the plastic mount
allowing the camera to move and spring back into place. Bunnings Hardware
supplied the camera tripod bolt and the washers (from the plumbing
department).
Results
Racing
video promises to be an invaluable training aid if discussion
at Cafe Racer in St. Kilda is any indication. Those far more
experienced in the art were able to identify strategic moments in the
race where your Wombat Team member allowed emotion to overcome racing
common
sense.
Essentially, in a criterium race, the rider
must conserve as
much energy as possible, only using it when opportunity presents
itself.
Those skilled in the art are able to see the tell tale signs of
vulnerability in a peleton where we lesser
riders obliviously
pedal on. At the moment of weakness (and only at that moment) brains
give way to brute force (provided the rider possesses such a power)
and propels himself in to the winning position.
Landing at Cafe Racer
where "The Coaching Panel" deliberates err perhaps pontificates over
these videos?
And
therein lies the true value
of WombatCam. It's one thing to theorise about strategy over a coffee,
but it's entirely another to have the wiley old medalists (or "The
Coaching Panel") point out actual examples of what to do and when (also
over coffee however). And in the case of this Wombat Team member, what
not to do...
Where to from here?
The
next most obvious step is to superimpose data from the Polar Cycle
computer
onto the image (heart rate, road speed etc). Polar data is also
time-coded so that matching it to
the
video time-coding on the computer after the race should be
possible.
Heart rate, cadence, speed,
lap-times, power and more can all be
sub-titled on the screen for later viewing and analysis. Once this data
is available The Coaching Panel will
recognise that your Wombat Team member also needs a significant amount
of fitness training to
capitalise on peleton weaknesses. But does one do interval training or
strength training and in what proportions?
The
data mixed video may be
able to reveal all.
Technical (Geek) Stuff
"The
SPCA533A is a highly integrated solution
for DSC (Digital Still
Camera) application. It consists of image processing engine, image
compression engine, the storage interface controller, TV encoder, LCD
interface controller and USB interface. The SPCA533A supports a wide
range of sensors, including most-commonly used CMOS and CCD sensors.
Flexible control of the internal buffer allows the SPCA533A chip to
support up to 4-mega pixels image resolution. It also supports many
flash memory card interfaces, including CFC, MMC, SMC, and SD. The
SPCA533A can also interface to both TFT LCD panels and STN LCD panels
for preview. With full support to a DSC's major
peripherals, customers can realise a DSC system with the
minimum
cost." from
SPCA533A datasheet - General Description. For dummies, that
means
a
single
Integrated Circuit or IC for the whole camera that does all these
wonderful things - and it's so darn cheap!
See also How to repair a carbon fibre frame
