Hi,
Does anybody know how to make an ultrasonic range finder like the ping sensor? I have bought two Long-Range Ultrasonic Sensors (Ultrasonic Sensors the third one down) and am clueless as to how I should hook this up to the arduino. I tried connecting one end to the a Pwm Output and the other to a pwm input.
Thanks
Try searching the forums. There are plenty of topics on this.
You can't just hook them up directly to the Arduino. The transmitter portion needs to be amplified (think 15- 18 volts... looks like those are 20 max) Also the received signal needs to be amplified before the Arduino can be able to detect it. Along with that you may want to add some filtering.
You can use the design for the SRF-04
http://www.robot-electronics.co.uk/htm/srf04tech.htm
Thank you so much,
the link helped a lot, ill try it out tomorrow.
hi, im new here, and if you are interested yet. I m develop my own ultrasonic range finder. Here the url to download the schematic.
http://rapidshare.com/files/420291560/ultras.pdf
PD: Sorry my bad english 
I posted this in another forum: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1283933873
For about $20 in parts and an Arduino you can build an ultrasonic ranger that you can configure to your exact needs.
There are plenty of Ultrasonic Range finder modules available on the market, few if any provide a “full range” image of the echo complex, merely providing the range to the closest target. Moreover, most lack a true analog representation of the return echo, i.e. echo range and amplitude. The following project provides all of the above, can be modified to meet the user's exact needs, and is relatively inexpensive.
Quick Start: http://majolsurf.net/wordpress/?page_id=829
How It Works PDF: http://majolsurf.net/projects/documents/100830%20Build%20Your%20Own%20Ultrasonic...
Parts:
(1) Maxbotix-UT Ultrasonic Transducer (sparkfun)
(2) OpAmp Modules BOB-09816 (sparkfun)
(1) 64 Logic Cell CPLD (or Amani/Kemani Dev Kit)
(2) 0.1uF Ceramic Capacitors
(1) 4.7k Resistor
(1) Breadboard