Outdoor tracking

If you took the heavy battery, motor and wheels off the device, you could sling it over your shoulder, and it is hard to imagine it following any closer than that.

I'm halfway through a golfbag project of my own. I'm using a wii made wireless to control the speed of the cart, and one of the buttons as cruise control.

so the robot/bag knows to stop before running down the user

Oh Richard you have spoilt the surprise. :wink:

Yes the sun will be an issue with IR detectors. You could try modulated IR. The best solution could be a GPS receiver on your belt transmitting your position to the bag robot. Then the bag robot has a GPS so it knows where it is and then it can plot a course to you.

P.S. In the UK the term Bag Lady is used to describe a female tramp or bum. So the term Bag Robot might have different meanings in some parts of the world.

Yes the sun will be an issue with IR detectors

Someone should have told this well-known, self-agrandising professor of cybernetics:

Yes i known that i can carry the bag, i can also walk to work and walk to the TV to change the channels! This is not a project i want to do because i am lazy (cough: i guess i am, but innovation is made by lazy people!)
This is a project i want to do because it is fun and challenging -> everybody can make a led blink........
And it has been done: GoGo "follow me" golf trolley. http.//www.omgsrl.it - YouTube

Problems with different sensors:
IR -> can be disturbed by the sun
Maybe some kind op blinking IR transmitter and the receiver should detect that "code" - and the direction could be 2 (or more) receivers separated by a plate parallel to the straight forward direction -> so that if the left receiver sees the signal, but not the right one the bag has to go left!
But my "worry" is that the IR receiver cant see the blinking IR transmitter, but only "sees" the sun!

ultra sound -> maybe not so good in rain and wind !

Gps -> expensive! and is it accurate enough? i meen what is best case 2,5 meters ?

But my "worry" is that the IR receiver cant see the blinking IR transmitter, but only "sees" the sun!

By blinking do you mean modulated?

The ides is that the amplifier of the incoming IR signal is tuned and only amplifies the modulation. Of course that doesn't help you if the receiving sensor is saturated.

Gps -> expensive

Yes

i meen what is best case 2,5 meters ?

No much more accurate than that. You can get accuracy down to about 1cm. Then you trade off price for accuracy.

Hehe!

Yes! accuracy can be under 1 cm (with a price of 20k$)

In everyday GPS handheld units its about 4-6 meters!

(with a price of 20k$)

Being ripped off here, don't need to spend more than $3k

In everyday GPS handheld units its about 4-6 meters

Yes but you want relative accuracy not absolute accuracy in your application.

So they are 4-6 meters out in the absolute coordinate system, but more precise relative -> that was new to me!

How precise are the cheap gps units relatively?

And can you recomende one?
Remember i need 2 if i am going for that solution, so cheaper is better :wink:

So when i said that a GPS isen´t accurate enough it wasn´t untrue!

Hmmmmm! There must be some kind of "sensor" that can do the job!

You need to notify the general area that you have an autonomous golf bag with a mind of it's own... maybe you need to have it wear a T-SHIRT when it moves on its own.

Like maybe this:

The major causes of error in a GPS system is the difference in propagation through atmospheric cells. WSS compensates for this locally. I would disagree with what Richard said

A small child could do it

OTOH, an autonomous machine is unlikely to get bored and start hitting its sibling with the contents of said golf-bag

LIDAR

I would love to see a practical, real-world example.

Well, WAAS has already been mentioned.

Differential GPS does the same thing, on a smaller scale. It uses a fixed station at a known point which calculates errors and send them to the mobile unit for corrections.

An obvious example would be one of those spiffy military GPS units, like those used on JDAMs, cruise missiles, etc, that use the second (still encrypted) GPS frequency that's far enough away from the ~1.5Gz signal we mere mortals use that the atmospheric distortion can be compensated for onboard.

-j

http://cgi.ebay.com/Arduino-GPS-Netduino-GPS-receiver-w-tutorial-Sparkfun-/250686123796?pt=GPS_Devices&hash=item3a5e0eaf14#ht_499wt_1048

Get two of these and xbee's, you can easily have your cart follow you.

So you think that theese gps units are precise enough relatively??

What is the purpose of the xbees?

Ok i wasn't totally awake when i wrote this.
I was still focused on "ir tracking" but using gps the cart off course need to know where i am :wink:
This is an expensive solution, i need to know if it is stable enough.

Perfect. All Mr. Pulse has to do is increase his GPS budget by 20x

I'm not sure of the cost of a DGPS rig. I'm sure comercial is expensive because of its applications, but I don't know if one can be homebrewed.

and then have his robot and the target both stand stock-still while they make a precision fix.

Wrong.

-j

A cheap and quick solution:

A thin rope attached to you, and to a joystick on your bag.
When you move it will pull the joystick on your direction and then let know to the Arduino where to go.

Another way could be a 360° coverage based on ultrasonic long range sensors + a button to start and stop the stracking (and avoid your bag to follow a rabbit crossing arround)