Server robot -- Background, purpose, and approach

Bob Smith wrote:


If you are building something from scratch,
have you thought about humanoid type robots?
Apparently they only take 4 days to design and one day to make
these days.  http://www.enemygadgets.com

I would be very pessimistic about the odds of building a reliable
humanoid robot that would be steady enough to carry a glass.  Unless
there's a compelling reason for humanoid, stick with wheels.
--
As we enjoy great advantages from the inventions of others, we should
be glad of an opportunity to serve others by any invention of ours;
and this we should do freely and generously. (Benjamin Franklin)

Joe Pfeiffer wrote:



Wheels can't get over steps without spilling.
That is a very compelling reason.

Three legged humanoid robots - now there is something
worth thinking about especially if you can custom build it
in 4 days.

As to where you might put the third leg...

ok ok back up a bit...

..don't even think about where that 3rd leg could be fitted.

Instead seriously think about where it should be fitted.

Could a motorized dynamic suspension be used controlled by motion
sensors?

JC

Only in an environment with lots of steps, which basically lets any
ADA-compliant environment out.  The robot really only has to be able to
get over anything the OP's boss can.


A mobile three-legged stool isn't particularly humanoid.  And you've
still got to keep from spilling.  And you've got to convince the OP (not
me -- I almost made that mistake!) it's really do-able in four days, or
even just in some reasonable time frame.


Umm.... what?

Something I noticed on the first post, but decided not to ask at that
point:  since your email address is from the enemygadgets.com domain,
and your first post included a link to that site, what exactly is your
relationship with that site?
--
As we enjoy great advantages from the inventions of others, we should
be glad of an opportunity to serve others by any invention of ours;
and this we should do freely and generously. (Benjamin Franklin)

Would a second hand motorized wheel chair be a good option?

It could still be used as a wheel chair only with a pc bolted on
controlling the toggle control with stepper motors.

And to keep it simple if a line following method was used where
the line is on the ceiling?

JC

casey wrote:

   This is a good idea but maybe for later.  Some of the doorways
in his house would be difficult to navigate with a wheelchair.



   This is a good idea.  You can't use a simple photocell but a
webcam could probable pick up a ceiling line well enough.  Using
IR visible paint would make the lines inconspiciuous.  Drawing
the lines on the ceiling would be a pain but should only need to
be done once.  I'll suggest this as an alternative if the 6 bit
bar code on a sheet of paper does not work out.

thanks
Bob Smith

I have never head of "IR visible paint".  Can you tell more about it.

I know that decades ago, there were some commercial inside mail
delivery robots that followed lines on the carpet. The lines were
drawn with invisible fluorescent ink, that only showed up under UV
light.  It was like the invisible stamps they put on your hands at
certain events to allow you reentry.

If this interests you, then there are some other considerations. I've
played with applying invisible UV ink on various surfaces with varying
degrees of success. A dark or even medium-dark surface doesn't work
well. And, you would also need a surface that doesn't already
fluoresce.

Joe Dunfee

Isn't this the wavelength that heats things?

They have expensive cameras that show humans and other animals
that "glow" in the dark with infrared radiation. They use it to find
hot
spots on walls to reveal termite activity.

I guess you would need a wire that heated up without glowing red
in the visible range.

JC

My initial guess about the post is that they either really meant UV
fluorescent paint that glows under UV light, or perhaps IR fluorescent
paint that glows under IR light (this is not as common as UV
fluorescence, but it does exist).

However, I don't think either is viable for use on a ceiling.  The
fluorescent paint I was suggesting was for use on the floor, where the
robot can shade it from the visible light, and so allow the sensors to
get a good image of the invisible paint line.

For the ceiling one alternative is to use retro-reflective tape.  You
can purchase vinyl non-adhesive tape intended to be sewn onto
clothing.  If applied to the ceiling, then it would provide a way for
any camera to see a very bright line.  E.g. if the camera were
surrounded by a set of IR LED's, the camera would get a bright
reflection of IR light from the line. It would be easy for the
processor to distinguish this line from other minor objects in view.

What is nice about applying something to the ceiling, rather than the
floor, is that it will always be in view, and will not be worn out by
people walking on it.

As for a method of making this line... I would want to avoid paint,
because it would be difficult to cover up later.  It tends to be a
thick paint that would leave a ridge.  I would also be nervois about
using an adhesive tape, for fear that it might not stick over the long
term, or if agressive enough, might not come off so well.  Maybe the
vinyl strip can be applied to pieces of wood strip (perhaps 1/2" wide
x 1/8" thick x 48" long) that is nailed to the ceiling at perhaps
every 24" (or where the rafters are).

Joe Dunfee

[...]

[...]

A simple method I used for a couple of toys I made for the grandkids
was based on the "the ceiling is easy to find" idea.
Basically, to locate yourself in a room find a couple of corners
(just look up at a roughly 45 deg angle and the corners will be
visible most of the time -- just look for the "Y") and estimate
distance using the upper angle. Even a piecewise linear approx turned
out to locate the toys within about 1 m even in reasonably large rooms.

The kids were happy for 10 mins, anyway. What can I say -- gen Z. ;)

--

If your ideas are any good you'll have to ram them down people's throats.
  -- Howard Aiken

That's a great idea.  I'll need to locate the robot in a several
room apartment but the corners idea should still work.

Do you any code available for it?

thanks
Bob Smith

[...]

The corner recog was done using OpenCV, if C++ will run on your platform.
If you have an x86 to do at least the crunching (I use "on bot" intel atoms
with cheap usb vga webcams rather than long wires or wifi) you can
probably get it working pretty fast.

But the code may rely on the kinds of interiors you find around colleges
and some of the more college-like factories -- i.e. walls off-white,
ceilings brighter white, and cheap fluro lighting that doesn't turn the
ceiling into a uniform (reflected) light source.

--

If your ideas are any good you'll have to ram them down people's throats.
  -- Howard Aiken