Sensor use to detect obstacle

I have found many papers on using a sensor skin (large numbers of IR sensors) on a robot arm to detect an obstacle to avoid any collision.
I was wondering <b>whether it is possible to use minimal numbers of sensors to do the same purpose</b>, i.e, measure the distance from the robot arm to the obstacle which ultimately using the developed software to compare it to a threshold value? If the measured distance is less than the threshold, then collision is detected and the robot would be ordered to stop operation or change path.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.