[Richard100]

Use the LV-maxsonar-EZ sensor from MAXBOTIX. This sensor was included in last year's KOP. Using a single sensor is fairly easy to set up ... connects to an analog input. Using LabView, you would use the Analog - Get Voltage VI, scale the value obtained for your choice of units (like inches), and offset the scaled value to put the 'zero' position of the reading at your front bumper (or wherever).

Multiple sensors are a bit more tricky since they can interfere with each other unless you arrange them electrically in a ring configuration and can initiate them with a very fast pulse. (This isn't an issue if the sensing areas do not overlap, but sometimes this is exactly what you want.) The ring arrangement essentially time-shares the 'pings' by forcing the sensors to take turns. This should also effectively discriminate against pings that other robots are sending (using the same sensor), and will cut down on false reports.