K-Dog

Hello,

I've been working on a few ideas on a Indoor Position System. I am still in the reasearch phase of my Masters. Whilst I know my idea is not novel, I still wish to presue my IPS which is based on angles not distances.

Can someone please point me in the right direction for RF based beacons and communcaition. My idea is simple, but is based on the robot being able to search for a beacon, and once found stop so that the robot is facing that one particular beacon.

Is there such a thing as a mono-directional rf antenna or locating system? If so can you offer me some help?

Cheers

K

Nigel Goodwin

A parabolic dish is probably the most directional, but yagi's aren't bad.

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Krumlink

I was thinking of attaching a SHARP IR detector to a servo, and have it scan the room until it picks up something moving. Just a idea.

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MechTronics

Nigel Goodwin

Have you looked at the operating range of those detectors?.

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PIC programmer software, and PIC Tutorials at:
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Krumlink

You can use the analog versions of them and a ADC to select what values to react upon

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MechTronics

Nigel Goodwin

Yes, I was thinking of that one, but what's the range of it?.

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PIC programmer software, and PIC Tutorials at:
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Krumlink

http://www.acroname.com/robotics/inf...arp/sharp.html

near middle of page.

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Nigel Goodwin

Exactly, so you're well aware of their limitations?.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

Krumlink

You could use 2 of them (far range and close range) or ultrasound sensors (bit more expensive)

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K-Dog

Thats exactly what I wanted to know. Thanks for your help Nigel Goodwin. The trouble with the IR Rangers is that line of sight is required. I did not mention it in my first post, but the system cannot be line-of-sight.

Mainly because if the robot is in an office or something, a person, computer, or some object may block the path to the beacon.

Rf is the solution as long as I get a fairly decent transmitter.

Cheers

jpanhalt

Sorry to come late to this thread. If I get the picture you propose, the robot will search for a narrow RF beacon. How will it know the beacon is on and in which direction to search initially?

From the 1960's to about the present, aircraft navigated by an OMNI system. Older systems (NDB, non-directional beacon and AN) were also used. And of course, GPS is replacing Omni. The Omni system allows one to determine position (azimuth from the transmitter) by determining a phase shift of the transmitted signal (AN used Morse code). John

Edit: Here's a reference for omni (VOR):http://en.wikipedia.org/wiki/VHF_omnidirectional_range
Corrected technical aspect of the NDB and AN systems.