Arduino reverse obstacle sensor for cars

This is an instructable for making your car reverse/backing/parking obstacle sensor. The full story in on my blog:
http://liudr.wordpress.com

With this obstacle sensor, you can find out your car's distance to another car behind it while backing. You can get as close to another car as a foot with the help of the sensor, yet not hit the car while backing.

The distance to your obstacle is displayed on an LCD monitor in foot/inch, mm, and bar graph. You will also hear an audio alert. As you get closer to your obstacle the audio alert beeps more frequently.

Step 1: Step 1 care for principle of operation?

As a physicist, I have to lecture on the principle of the sonic ranger a bit. It is a rather simple device, the small cousin of the police speed gun! The sonic ranger sends a few pulses of supersonic waves and waits for the waves to bounce back from an object in front of it. Once it detects the reflected sound, it knows how much time it took the waves to travel a round trip from the ranger to the obstacle and back. With speed of sound at around 340m/s, you can calculate the distance to an object. You can also find velocity if you measure distance at two consecutive times and do distance change over time. Bats use their sonic ranger to fly in pitch black caves or catch food! Mr. English also tried the same technique with no apparent training and failed miserably. One episode of Stan Lee's super heroes also featured a blind person using his tongue clicks to tell what's around! That's it for sonic ranger intro!

Comments

[liudr]

Wow, my first every instructables post became a featured project!
I will be mounting the detector with the new (black plastic housing) on my car this weekend and see if I can back towards a garage door within a foot, which I can never do with the high trunk and poor rear view inside my cabin, and then try it blindfolded!

[quatch]

how did it stand up to time? Did you end up waterproofing it?

[samwhiteUK]

As an arduino owner looking for innovative ideas and a soon-to-be learner driver, this may well be something I give a go!