Heli robot ?

I think you'll have your work cut out with that Heli. I've got the one
before it, and whilst it's a bit of fun it's really not cut out for
modding, it simply don't have enough lift (A couple of sensors and
it'll never get off the ground). Check out this forum for heli-bot
projects...most impressive!







Dave wrote:

These counter-rotating blade helicopters make the flying easier, so it
stands to reason it would be easier to automate the thing. I've had it
on my to-do list, but like so many things...

As long as you keep the weight down it should be doable, so the weight
is the real challenge. The Bladerunners already use lithium batteries,
but maybe you could find a more efficient motor (and a higher price)
that would give you a better weight-to-lift ratio. Your electronics will
probably need to be constructed on a small carrier without a PCB, as
even a small PCB would add too much weight.

Look for segments of the body you can remove or cut out to give you a
little weight benefit.

-- Gordon


Dave wrote:

There are lighter LiPo batteries available. I'm not so sure about the motors
(it uses two for the main drive, plus a really small one for the tail
rotor). The body is foam.

You need to determine your approx distance from walls in six directions, but
if you assume that the room does not change in size whilst you are flying,
then you only need three measurements. It looks like a good application for
ultrasonics, but using multiple sensors adds weight (A single Tx or Rx is
3g, SRF04 is 10g) I wonder about a single sensor pair, with some kind of
rotating 'horn' to provide directionality.

PCBs don't have to be 1.6mm thick ! You can even get flex pcb stuff for
prototyping, which is nice because you can bend to fit in available space.

Still looking for ideas about heading 'lock' - a magnetic compass near high
current stuff doesn't look ideal ...

Dave


Gordon McComb wrote:

Now here's a challenge!

http://www.trendtimes.com/picco-z-rc-helicopter.html

ha ha..seriously this is the one I was thinging of modding:

http://www.trendtimes.com/drrchebabopa.html

or possibly

http://www.trendtimes.com/6chdrrche.html  not sure about the 6 channels
thought - a bit much to start with I think!

Mark




Dave wrote:

I can tell you from experience that the larger they are, the harder they
fall - I guess that they really make their money on the spares !

Dave

markwod@yahoo.co.uk wrote:

So have you got this one:

http://www.iwantoneofthose.com/Blade-Runner-2-Helicopter/index.html

or this one

http://www.trendtimes.com/smallest-rc-helicopter.html

I have the v1.0 version of the first one...not the most stable of
things. Reason I ask is because you mention a gyro....

Mark

Dave wrote:

I have the first version (BR2) - I think the critical difference is in the
two counter rotating main rotors - the tail rotor points up and down, and
merely tilts the body for forward/backwards. I haven't verified that there
is actually a gyro, but from the behaviour there must be one.

Flying is fine unless you spend too long near an obstacle - if you do there
seems to be a circulation set up that sucks you towards doom ...

Dave

markwod@yahoo.co.uk wrote:

I would think that you should keep as much of the electronics off-board
as you can.  Perhaps put a surface-mount LED infrared beacon on the
heli, and determine its location from two (or more) cameras watching
from the ground.  If there were 3 beacons on the helicopter, then all 6
DOF can be calculated.

I've seen plenty of projects using the LED beacons at universities.
They are use as a 3-D pointer for Virtual Reality setups.

Another idea, which doesn't seem as good is to use the noise the
helicopter makesas a means of location.  An array of 3 microphones
could be used, and this wouldn't requiring any modifying of the heli at
all!

If the sound from the helicopter doesn't put out a distinguisable
element (a "ping" type sound) then you can identify it with a computer.
If it doesn't put out such a sound, perhaps some mechanical means can
be added by putting someting that touches a gear and generates a sound.

The idea is to calculate the time it takes for a sound to get from the
heli to each of  the 3 microphones.  Each mike would calcuate a
distance from the time, and narrow the location to the surface of a
sphere around that particular microphone.  The final determination is
made from the intersection of the 3 spheres.

I am not certain how you do this without knowing the time the sound
first eminates from the Heli. Though, I am sure there is a way.  But,
one source of that time could be electrical noise generated from the
brushes on the main motor.  By comparing that electrial static burst to
the time of the sound, you can get distance.

However, this would only give you a location, and not the kind of
detail you would need to truely fly a helicopter unless it had
significant on-board stablization ability. I don't see any possibility
of extracting roll,pitch or yaw information from sonar.


Joe Dunfee