Recommendations: Proximity Detector for Car

Greetings! I have a project in its nascent stages and I’d love input from minds more experienced than mine.

Context:

I am a programmer, but have little experience with robotics. I have acquired a beat-up old car I intend to take down some dirt roads out in Utah. These roads can have rocks capable of busting valuable parts underneath the vehicle. Merely watching out for these obstacles is not wholly reliable. I’d like to integrate a system onto the car that detects objects that are tall enough to pose a threat to the car’s oil-pan or axels. Ideally, detection can take place over two stages: 1) as car approaches an obstacle; 2) a back-up system: as the object passes under the very-front of the car.

I was thinking a combination of a Maxbotix sonar and LIDAR laser rangefinder (or something along these lines); perhaps the former could detect objects the car is approaching, the latter could be used to detect objects that are passing under the car that are too close to critical vehicle areas.

Thoughts?

Really happy you’re a programmer since it will be programming intensive. Since you want to watch out for obstructions in two dimensions, you’re best with a 2D sensor:
robotshop.com/en/lidar.html
Ex: robotshop.com/en/hokuyo-ust- … ction.html

However, most of these are not meant for outdoor (all weather) use, and dust / water will damage them (check the specs). Anything that can block the laser will cause issues with the readings.

This unfortunately means several 1D sensors which are dust / water resistant might be best:
robotshop.com/en/benewake-tf … -10-m.html
robotshop.com/en/benewake-tf … -22-m.html

These two are optical, so anything which causes obstructions will create issues.

A weather resistant set of ultrasonic sensors might be good, but they don’t have a focused beam. Examples:
robotshop.com/en/maxbotix-wr … range.html
robotshop.com/en/maxbotix-xl … inder.html