View Full Version : When is IR better than SONAR ?

12-28-2005, 07:00 PM
I have always implemented obstacle detection and avoidance using SOANRS but I have heard that a lot of people prefer Ir.

So can anyone tell me what are the advantages of Ir over SONAR except from being cost effective?

12-28-2005, 07:20 PM
None if both are availible .

12-28-2005, 10:35 PM
Only difference in IR and sonar is color differntiation capabilities of IR exploited in making Line followers..

but when it comes to obstacle avoidance, then ditto what Vikas said


12-29-2005, 08:53 AM
There are differences between Sonar and IR - Each has its merits and demerits -

Sonar is good for long range obstacle finding/avoidance where as its hard to get that range from IR.

BUT - IR has much higher resolution due to smaller beam-width.

Since the beam-width of Sonar is very wide, its hard to distingush between obstacle and freeway in long range - whereas the narrow beam of IR is much better in this case. for example if the robot is trying to turn into a narrow passage with a corner of a wall in begining, the corner might reflect the Sonar beam back and the robot might never "see" the opening of the passage.

Sonar may have multiple reflections...and the calculated distance from angular obstacles will be different..in IR multiple reflections is almost practically impossible phenomenon.

ofcourse the best way is to have both kind of sensors...sonars for long range and a rough idea of envioronment, and IR for higher resolution + side-looking sensors.

moreover, the response time of sonar and IR is known to all.

and for very short distances, sonar will not work well

i had both senors in one of my robot because sometimes sonar used to miss seeing the thin leg of a chair, whereas the IR could.


01-03-2006, 02:27 PM
sonars ll not work for very small distance....
they cant differentiate b/w black and white surface{contrast}
u need gud filtering technique's at the receiver end if u r making ur own module....
but they work really well for obstacle avoidance....

09-20-2006, 08:21 AM
can anybody say what is meant by short distance in cm ??

12-10-2006, 01:24 PM
ir can be use as beam sensor with the help of some convex lance assembly