In this web http://www.cl.cam.ac.uk/research/dtg/attarchive/bat/ a group of the Cambridge University Computer Laboratory develops a way of 3D positioning using 433MHz and complex algorithms. This was on 2002.
I researched a bit about RFID but I think they don't locate exactly the position, they just know wether you are inside a certain room or not, I need certain position inside a room.
I'd like to know if any of you knows if today, 2014, are there easier/cheaper ways to achieve this and using Arduino as the controller. I know it's kind of an open question, but any help is well received, also it doesn't matter if it not on 433 Mhz.
That website talks about a system using ultrasonic transducers on the ceiling, not 433MHz for position location. The 433MHz is purely for a data link. It merely looks for the strongest signal and places you somewhere in the vicinity of that ceiling mounted transducer.
Time of travel in a short distance is not an easy thing to do.
Rather, send out an RF signal that is sweeping across a short frequency range, compare the reflection with the transmitted signal. The further the reflections have to travel, the greater difference in frequency between the local and reflected signal. It is also called a chirp.
Otherwise, you can compare the phase of the local and reflected waveform. Not something you can accomplish with the analogRead() capabilities of an Arduino.
Time of travel in a short distance is not an easy thing to do.
That depends on the speed at which entities travel over that short distance, the accuracy of your clock and the means at your disposal to signal the start and end points of the travel.
In this case, a nearly one million to one ratio of signal speeds is a pretty good starting point.
I got confused, I though every signal over 20khz was ultrasound. I mixed up ultrasound and radio frequency I guess.
I'll chek out about the 27cm3 volume.
Thanks for replies.
It is only sound if it travels by vibration of atoms or molecules. If it travels by photon, it is radio or light, or ionizing radiation. You can have radio waves at 1kHz, and sound at 2MHz. It isn't the frequency that determines which it is.
polymorph:
It is only sound if it travels by vibration of atoms or molecules. If it travels by photon, it is radio or light, or ionizing radiation. You can have radio waves at 1kHz, and sound at 2MHz. It isn't the frequency that determines which it is.
That's what I wanted to hear! It isn't the frequency, instead it's the nature of the wave. Thanks a lot.
And talking about waves and comm links, I found not only RF can transmit info, light too (search for Li-Fi).
Someone at a makerspace I was at had printed and put up a miniposter illustrating hertz vs cycles per second, but on a lin-log scale. I laughed out loud, then I found out that the person who had posted it was dead serious and didn't get the joke.
Like this:
That particular image is from this website. To newbies: please note the date when the given formula was written.
Robin2:
Shoot .... I was looking forward to something that would find bats flying at night.
...R
Comedy aside , if you are serious maplin do a bat detector for 25.
I dont need one as i can see them, still trying to get a photo though for 3 year now.
