Here are some video things I've been working on.



Camera overlay:


If we are including ATV on the first flight, we're required to include a
visible amateur radio call sign (Glenn?) in the transmitted image.


To do this OSD (on screen display) we bought a couple of "BOB-4" boards.
I've got them in my basement.  The image quality isn't fantastic, but it's
about the only unit we could find that fits in the airframe.


According to the BOB-4H documentation, we can store the FCC Amateur Id in
its boot script, which is held in Flash and executed on power up and on
reset.  If the documentation proves to be true, we can pre-program the unit
with our desired call-sign and mount it in the avionics module.  Then, we'll
only need +5VDC, GND, video in and video out.  That should be EASY to put
into the first flight.


I have a breadboard and connectors and I might be able to show it next
Wednesday.  The main thing to remember is really good shielding of the
entire BOB-4 -- the documentation specifically says that it can interfere
with GPS receivers.



Camera rotation:


This is definitely NOT required on the first flight, but may be relatively
simple to implement (IMHO, but I'm a SW writer and an artist, not an ME).
At the least, we could design a fixed camera mount that can accommodate a
rotating camera in a future flight.


Why talk about rotating the camera?  It'd be useful to look down for launch
and ascent, up for parachute deployment, and straight out for the rest of
the ride down.  And maybe look down again prior to landing.  


Previous flights had a mirror or prism that looked down until the parachute
deployed.  Then the prism was blown off so the camera could look outward for
descent.  Since the camera was rather large, it had to stay inside the
airframe to minimize drag. 


Andrew, Glenn and I have had ongoing discussions about using multiple camera
images to look down, out, up and show data.  But using separate cameras
would require multiple ATV channels and/or screen multiplexing.  I think FCC
has a limit on the number of ATV channels that can be used simultaneously in
one geographic area.  The only multiplexers I've been able to find are
wither rack-mount devices or built into a TV monitor.


With the really small cameras and lenses that are available, such as the
ones we just bought, placing most of the camera outside the aeroshell
becomes conceivable.  The camera we just purchased is about 36mm x 36mm.
Its lens is about 14mm in diameter.  If we stick the lens against the
aeroshell, the camera body would extend about 25mm.  The area that
contributes to drag would be 36x25mm: about 900 sq mm, or about 1.4 sq in.


The camera can be rotated by a servo inside the airframe without too much
trouble and driven by a PWM signal from an ARM7 node. I've cobbled something
together that I'll try to bring in on Wednesday. 




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