View unanswered posts | View active topics It is currently Thu Jul 24, 2014 7:16 pm






Reply to topic  [ 3 posts ] 
Max. US sensor range? 
Author Message
Rookie

Joined: Sun Dec 09, 2007 9:00 am
Posts: 2
Location: Berlin, Germany
Post Max. US sensor range?
Hi,
i´m just starting programming with RobotC. So far it is pretty easy, also for a C-dummie like me.
After some curious behaviours of my rover i discovered that the US sensor reports only up to 160 cm valid values. After 160 cm the sensor reports only 255. I now noticed that the sensor reports 255 for not valid readings.
So, is 160 cm the max. distance? So far i know, Nxt-G supports up to 250 cm!?

regards and thanks,
Frank


Sun Dec 09, 2007 9:24 am
Profile
Expert
User avatar

Joined: Fri Nov 09, 2007 4:51 am
Posts: 121
Location: Hungary, Europe
Post Re: Max. US sensor range?
Frank Steinhauer wrote:
After 160 cm the sensor reports only 255.


The US sensor calculates the distance on the measured travel time of the sonic pulse from the sensor to the remote object and backwards. However, it requires a certain level of the reflected signal.

If the remote object reflects too little amount (because of its small size or absorbing surface) the US sensor will not detect reflected signal and will respond "255."

When I try to measure the distance of our ceiling (flat, plain and hard surface) the US sensor is quite good even if it is 240 cm from the ceiling. However, measuring the distance of the sofa is not that straightforward, the US sensor can detect the signal up to 1.5 m. The thin and round leg of the chair is detected only from 1 m.


Sun Dec 09, 2007 12:55 pm
Profile
Rookie

Joined: Sun Dec 09, 2007 9:00 am
Posts: 2
Location: Berlin, Germany
Post Max. US sensor range?
I tested now my US sensor with NXT-G and Robotc and yes, both comes up with results up to 250 cm. But Robotc delivered much more "255" numbers in the range 150-250 cm. The filter algorythm in NXT-G seems to be more "clever". I used in my test the standard "SensorValue" expression and the S1 jack.
Any hind to get better results?

regards
Frank


Wed Dec 12, 2007 1:19 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 3 posts ] 

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron



Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by ST Software for PTF.