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?
Step 2: Step 2 List of Parts
I've listed the parts here:
1. One arduino Duemilanove or UNO (many vendors sell this) http://www.sparkfun.com/products/9950
2. One Phi-1 shield kit for arduino http://dipmicro.com/store/JL-PHI-1
3. One RJ11 jack and breakout board. I made some breakout boards myself and used the RJ11 jack from the Phi-1 kit. But you can buy from sparkfun: Rj11 jack http://www.sparkfun.com/products/132 and RJ11 breakout board http://www.sparkfun.com/products/193 . You have to observe which pin is which with a multimeter.
4. One four-wire phone cable. Just go to a dollar store and make sure you're not getting two-wire cables.
5. One Ping or other ultrasonic sensor from parallax http://www.parallax.com/tabid/768/ProductID/92/Default.aspx . Alternatively you can also buy this one from sparkfun http://www.sparkfun.com/products/639 . You will have to make sure you're connecting the PWM pins to arduino. I don't have this.
6. One 1uF 25V capacitor. You can get it anywhere you buy the other parts.
7. Either a car power adapter that outputs center-positive 9V to 12V or a 9V battery with a connector from here http://dipmicro.com/store/BH9V .
8. Maybe some tape to secure the sensor to the back of your car.
Step 3: Step 3 Assemble and Test the Phi-1 Shield
This instructable has the steps to assemble the shield.
After assembly, test the shield with test code found on this page: http://liudr.wordpress.com/phi-1-shield/
The test code will ask you to adjust LCD contrast, press all buttons, and test out the buzzer and real time clock. You can try the alarm clock code and Morse code translator code on that page too. they don't need any more hardware than you already have on the shield.
Connect phone cord between the shield and the RJ11 jack with breakout board.
Without plugging the shield on arduino, use a multimeter to test the continuity so you know which wire goes from the shield to which spot on the breakout board. Here is the picture of the sparkfun RJ11 breakout board:
Step 5: Step 5 Connect Sonic Ranger to Arduino
Stick a 1uF capacitor (cylinder at the left end of the red-black-white wire) between 5V and GND to filter out noise. Trust me, this is not optional! Observe polarity of your cap.
I have made two versions of the program, a fully interactive one with menu and adjustable parameters. Another version is a nutshell, if you're interested in learning how things work quick.
Full version - interactive with menu and parameters
Nutshell version - powers up and works no parameters to adjust
Step 7: Step 7 - Field Test
Step 8: Step 8 - Make It More Permanent
I made a small casing for the sensor so I can stick some 3M command stuff in its back with "velcro" so I can easily attach it to my car and remove it during a rainy day!
You are done!
For more projects with arduino and the Phi-1 shield, visit me at http://liudr.wordpress.com