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Topic: Car reverse backing obstacle sensor with sonic ranger (Read 10543 times) previous topic - next topic


This is for my wife. She deserves a tech gift for putting up with all my wires and tools lately!  :D

I made a car rear obstacle sensor with audio alert. You can see how far something is behind your car when backing or parallel parking on LCD, both analog bar graph and digital readout. Plus it beeps like a Geiger Muller sensor when it comes closer and closer to an obstacle. I've tested it with a 12 ft phone cord. It's good to go on my car for a field test!

I've made two versions of the code, a nutshell version which turns on and does what I said it does, then the fully interactive version with all the menus and adjustable parameters so if you want earlier audio warnings or want it off, choose from parameter list and customize it! This hopefully helps beginners (nutshell) and advanced users (full)! Leave some feedback!

If you like the shield, you can buy it here:

All details and codes are on my blog page:


Videos (watch the bar graph!):




Feb 13, 2011, 05:18 am Last Edit: Feb 13, 2011, 05:37 am by liudr Reason: 1
Update: it's warm today (by our local standard) so I got out and installed the sensor with my wife. It worked!

12FT 4-wire phone cord, about 10 pieces of wide tape and some masking tape later, the sensor is on my rear bumper sticker. I had it on my trunk first but it is angled and too high. It couldn't detect a car but a garage door was fine. So I moved it to the middle of the rear bumper cover.

Inside my car:

Between my car and some other dude's car:

The mounted sensor:

One video:

Several more videos are on my blog: http://liudr.wordpress.com/2011/02/12/arduino-parking-sensor/
I plan to back my car into a closed garage door blind-folded (hopefully in the near future) and put my trust in physics and the audio alert!


I plan to back my car into a closed garage door blind-folded (hopefully in the near future) and put my trust in physics and the audio alert!

Very cool project. Hope the blind-faith test goes well.

But seriously dude, you need to work on your sensor mounting skills.  :D

I say go with either hot glue or double-sided tape.  ;)




Thanks! Forgot to mention I got some 3M "velcro" stickers with adhesive backing. Will plan for next weekend. Too much exams to grade. With cold weathers like in my area, you gotta be able to remove these sensors at night. I don't have a garage, although with my arduino spending I could rent 2-3 garages :) You just have to stick to what's more important!  :smiley-mr-green:


Who's talking now lefty? XD

Front side:

Back side:

Original box:


Who's talking now lefty?

You talking to me, you talking to meeeeee ?  :D

Cool. Now work on that sound, it should be a nice soothing low frequency gentle gong gong gong, picking up tempo. Yours sounds worst then my wife's shrill warnings for me not to back up to close to something.  ;)



Feb 14, 2011, 03:05 pm Last Edit: Feb 14, 2011, 03:17 pm by liudr Reason: 1
You mean increasing pitch as the obstacles get closer? Just several more variables I can put in my parameter menu! I have length of beep, length of silence, audio alert on/off in there already.Now I can add pitch, pitch ramp rate, and ramp pitch on/off. It's rather nice to have a parameter menu so I didn't have to re-upload if I don't like the way the pitch ramps.

BTW, that black box was made from a $1 3X5 card holder. It was black plastic sheets. I tore it down to make a face plate for my other project:

This picture was taken with a black paper face plate before I made the plastic one.

I just used a blade to cut on one side not so deep and fold at the cut. Then I spent a few minutes with my hot melt glue gun. There were also three sheets of cardboard behind the sensor to hold it in place.


the shield is arduino uno compatible?

ps: you got MP  :smiley-mr-green:


The shield is compatible with arduino UNO, Duemilanove, MEGA and all arduino clones that are pin compatible with all that were just mentioned.  8) :D


I think that I am going to copy this project a bit, I already have an arduino in my trunk connected to ignition, and a nice monitor in the front (for alternative clock and temperature sensors):

adding a ping or something would be interesting!
Federico - Sideralis
Arduino &C: http://www.sideralis.org
Foto: http://blackman.amicofigo.com


Alright! I suggest you got get two sonic rangers. Since I've installed my sensor, I've grown an additional sense: every time I drive, I look at the rear bumper covers of the cars in front of me. I've seen cars with 2 or 4 sensors spread around the bumper evenly. I think you will want wide angular response as well but mine was narrow so it measures more or less things directly in front of it and not so much for things on its side. Having at least two will be much better than one. You can use your display to show two bars, one for distance to obstacle on each side.


I'd like to do some test, I have here 2 types of sonic sensor... A parallax ping and a cheaper i2c SRF02. Probably I will wait for warmer days, as here in Italy for our standars :-) it's still cold ^_^ I like your project a lot!
Federico - Sideralis
Arduino &C: http://www.sideralis.org
Foto: http://blackman.amicofigo.com


Thanks Federico. It looks like you're already modding your car. Have you posted your project on Exhibitions yet?


This project is now a featured project on instructables.com  8)

I just posted it last night. I guess arduino + car is a big hit! :D



nice work
you might want to make the tone go continuous once you get below a certain distance (12" maybe)
or have a LED come on?
there are only 10 types of people
them that understands binary
and them that doesn't

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