Triangulation using RF

[moinkey]

Hi All,

I've been reading the forum and its great!

However im still having troubles understanding exactly how RF triangulation works and how i would implement it. I'll explain my project im planning to do and what i plan to achieve.

Basically there is a user and a robot. The user wear a 'tag' and the robot has 2/3/4 sensors or receivers that triangulate the position of the user and move towards the user. So when the user walks the robot follows giving a fairly poor resolution of +-30cm and the user will be no further than 5m away.

There arent a lot of restrictions on the receiver side besides that it cant kill the battery too quickly. Having said that the battery will probably have a fairly large capacity. Something like wifi is prob too power consuming.

The tag should be a small box running off AAA batteries or a 9V battery.

After doing some research i believe some sort of RF would be the best choice as the environment is outdoors and there may not always be line of site.

Are there any projects/devices that have already done this that i could reference to. If not then is it possible to get a high level schematic of how this would work and what i would need to prototype this?

Thanks in advance.

Moinkey

 

[transistance]

An RF tracker can do what you are looking for. Here is a link to a **broken link removed**. (Stalk much?)

You can code your robot to act more intelligent to be able to find the source with 1 receiver (this would not be triangulation in the real sense), or use 2 receivers placed apart to pinpoint the source of transmission. You will not need a third receiver or more unless you have a flying robot that moves in three dimensional space.

 

[Mr RB]

An RF tracker can do what you are looking for. Here is a link to a **broken link removed**...

Hey, your web page is broken, trying to right-click the circuit .gif to save the image doesnt work.

 

[transistance]

it's not my website; it's a site I came across by googling. I just tried it and it still works.

 

[Sceadwian]

What's the range you're looking for?

 

[moinkey]

Thanks for the response transistance. Your link works fine for me and seems to be a good little device.

The range im looking for is no more than 10m. 5metres is OK too. Resolution of about 30-50 cm. Basically i would like to robot to follow. As long as its going the right direction and is a couple of steps behind me then its good enough.

Cheers

 

[new_member]

Hi, very intresting topic!!
Id like to read more about this, but the link is broken. maybe sombody out there could provide me with new links about this whole "robotor following people topic"

i appriciate it

 

[MikeMl]

RF is almost useless at these dimensions. Use Ultrasound at about 40kHz to 100kHz.

 

[mneary]

I found a link by searching for tx15trak.htm and it sent me here: **broken link removed**
It looks like it might be the new location for the user.

 

[moinkey]

So after a good few months of work on it we finally got it working using RF - if anyone is interested there is a youtube clip : YouTube - GUTS in action
Me and my mate did this as a final year project.

 

[Sceadwian]

What do you mean using RF? The video shows and says that it's using ultrasonic sensors. Nice project though, I like the gimbals.

 

[ericgibbs]

What do you mean using RF? The video shows and says that it's using ultrasonic sensors. Nice project though, I like the gimbals.

hi,
I also thought he said it was ultrasonic.
Ref the gimbals, I would just a taller [deeper] trash can for the rubbish.

 

[Sceadwian]

Yeah me too eric, but I didn't want criticize the design too much =\ It worked, and I have a fascination with gimbals =)