tracking systems and PIC programmers [TANKS]

[anvilus9-at-comcast.net]

Gene,

> Gene Burbeck wrote:
> > Because it would be fun! I also think the tracking system could work
> > WITHOUT the assistance of the other tank, just not as well. I like your
> > idea about using  sonar. Do you know any of the specifics about how that
> > worked? I too was considering sonar a while back, but I couldn't figure
> > how to do it with the wide beam width of most sonar sensors. 

1)  About two years ago, I built a prototype turret that used a 1/4 scale servo
hacked for continuous rotation.  The servo had a small pinion that drove a
larger gear on the turret ring.  I used a standard Futaba yaw gyro to provide
turret rotation stabilization and it worked great.

The main issue in regard to turret rotation stabilization is - Who cares?  Our 
battles are conducted at such close range that short driving distance changes
the rotational firing solution dramatically independent of rotation stabilization, 
and the TARGETS move constantly.

2)  If you want to play with gyros, I strongly recommend vertical stabilization.
I have been hit many times in the upper body, throat and mask by opponents who
have excellent aiming skills and had adjusted a good firing solution at my tank.  
Unfortunately, if they drove their tank toward my tank and their vehicle hit a 
bump or rise in the ground, it caused their gun to point higher even though they 
did not change the vertical firing solution.

I must confess that I too have hit numerous people rather than their tank, but 
mostly because of my poor aiming skills.

3)  Triangulated sonar could work well for RC warships because the surface of the 
water does not cause spurious returns.  However when outdoors, medium and long 
range sonar in proximity to the ground provides dubious data due to echoes returning 
from the grass.  It could work at close range about 10 to 15 feet, but a paintball
hit from an opponent to a sonar sensor at that range would shatter it.

Place a Polaroid camera about 10 inches above the ground and try to take a picture of
a 14 inch tall object on grass at various distances.

4)  Near IR (around 1000 nm wavelength) can work well outdoors for tracking if you 
modulate the intensity at 38 KHz similar to television remote controls.  You can 
buy IR photo pickups such as the Panasonic PNA4602  that have narrow 
bandwidth about 950 nm wavelength and only respond to 38 KHz IR carriers.

Unfortunately, this means that your target must carry a very bright  omnidirectional 
IR beacon.  Most IR LEDs only have effective beam angles of about 20 to 40 degrees 
so the beacon would need 10 to 20 IR LEDs.

Alternately, I do not believe that your idea for using a swept IR beam to identify 
targets 
carrying "reflectors" would work either.  The reflectors would need to be 
ominidirectional.
We do use small omnidirectional IR markers (3-10 mm DIA balls covered with 3M 
reflective
tape) in photogrammetry for sports and clinical gait analysis, but you really need
bright IR illumination and a high resolution IR camera to see them.

About the only way near IR could work is similar to actual anti-tank missiles 
and smart munitions.  If you had a spotter who "painted" the target with a VERY 
bright IR beam, your IR tracking system might be able to lock on.  Unfortunately this
requires a second operator wearing IR goggles and carrying a military grade
IR laser.

Thermal cameras using long wavelength IR may or may not be able to identify
our tanks.  Although motors often get hot, the external thermal signatures of our 
tanks are probably not significantly above ambient on a hot day in St. Charles MD.

5)  After four years of active battling and numerous experiments with gyros, 
lasers and cameras, I do not believe that tracking systems will work in our 
hobby "WITHOUT the assistance of the other tank".

They could be great fun in the backyard but dubious on the battlefield.

From: Frank Pittelli <frank-at-rctankcombat.com>
> The winner will be the one with the better PIC software programmer on 
> his side :-)

I disagree.

Even the very best programmers cannot make tired antiquated hardware
perform better (e.g. Tiger T001).

More importantly, beware of NOVICE programmers who have not learned 
the "tricks of the trade" through the "school of hard knocks" because their 
code will  "lock-up" or get the "jitters" at the most inopportune moment.

Joe

--
Joe Sommer, Anvilus Machine Works
2378 Nantucket Circle, State College, PA 16803 
814.234.4773     anvilus9-at-comcast.net
http://www.anvilus.com