I currently have a SRF05 ultrasonic sensor (PICAXE) which does a great job in measuring distance. However I now want to be able detect if I can go around an object so I get my servo to move 45 degrees each side and try and measure the distance.
I have now found the ultrasonic beam width is very wide at about 10" from the sensor thus difficult to find out if its a wall or object I can navigate around.
The question: Does an IR sensor have a more focused beam at smaller distances. Could I have ultrasonic for long range and IR mounted on the same servo for closer detection of object edges. I have now realised I don't care about accuracy just repeatability and beam width considerations.
You could purchase a ultrasonic rangefinder with a narrower beam, look at the Maxbotix series of ultrasonic rangefinders, I believe the LVEZ0 has the narrowest beam.
The answers to the questions are: yes IR rangefinders will have a narrow beam compared to ultrasonic, and yes you can use both types of sensor at the same time. Doubling up your sensors could allow you to take advantage of the strong points of each sensor while helping to mitigate the weaknesses. There are other factors to considering in addition to the question of beam width. The SRF05 will give good results up to several meters, while any of the Sharp IR sensors I’m familiar with are only good up to half a meter or so. Also both the sonar and the IR methods will miss certain objects depending on such factors as the angle, shape, and composition of the object. Using both types of sensor will give you a hedge against false negative readings.
