Hello,
Sound travels at roughly 340.29m/s. D = vt. Using these two basic concepts I
want to build a navigation system for a robot.
What I've already done
Built a PCB with a condenser microphone that can pick up desired
frequencies. At the moment my PCB or beacon can pick up a 1500 kHz tone.
I am using some code I found on these forums to generate a 1500 kHz tone
through the computer speakers.
I am using a PCI-6229 and a SCB-68 where I have setup a 100 kHz square pulse
and am feeding it back into the PCI-6229 where I am count rising edges.
I've written some code that will store the number of counts when the beep is
sent, and store the number of counts when the sound beacon picks up the sound
and transmits the data via radio signal.
Working backwards, we know that 1 count equates to 0.00001s. Using d = vt We
know v = 340.29m/s. t is the function of the difference in counts divided by
the 100 kHz giving us the time. Therefore we should be able to calculate d.
The Problem
From 1m away the results always indicate 60 meters. I am pretty sure the discrepancy
in the counts is due to interrupt priority issues, labview is windows based and
processing power is being used else where, and that my code takes time to
process causing delays.
This is a time critical application and I have no idea where to go to next.
Things I have been suggested to look at.
- Look at
the lower levels of the language and try counting clock cycles for each
function. (would have a clue how to do this in labview)
- Using FPGA.
Can this be done in labview and with the equipment I already have?
Can someone shed some light on the matter please?
Thank You
Kamilan
P.S.
my current code and sub vis can be viewed here
http://forums.ni.com/ni/board/message?board.id=170&message.id=361796#M361796
