Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: superchiku on March 18, 2008, 11:58:14 PM

Title: other circuits for distance measurement
Post by: superchiku on March 18, 2008, 11:58:14 PM
can anyone plzz tell abt a schematic that can be used in distance measurement as sonar and sharp ir are not available where i live??
Title: Re: other circuits for distance measurement
Post by: airman00 on March 19, 2008, 06:21:47 AM
What is your application and also we need more details !

Like what range do you need, what objects are you ranging , your robot setup, etc.
Title: Re: other circuits for distance measurement
Post by: superchiku on March 19, 2008, 06:22:49 AM
robot must range between 3cm to 2m i have to use it in a sumobot to find the victim
Title: Re: other circuits for distance measurement
Post by: Ro-Bot-X on March 19, 2008, 11:41:08 AM
In a sumo contest you don't need to know the distance to the oponent. All you need to know is what direction the oponent is located. Take a look at the VCR robot, those IR sensors can detect the oponent and give you Left-Center-Right directions. If you need more precision in finding the exact angle the oponent is located, mount only one pair of IR LED and Sensor on a servo and use it as if it were a Sharp sensor (but like a digital On/Off sensor). To narrow the detection angle, use a narrow beam LED and a piece of tubing in front of the Sensor. Then you can use Stampy code for oponent detection.
Title: Re: other circuits for distance measurement
Post by: superchiku on March 19, 2008, 10:57:45 PM
yes simple ir can help but still the range will not be much and i need good range
Title: Re: other circuits for distance measurement
Post by: Pratheek on March 20, 2008, 12:31:00 AM
If you need good range with ir then use modulated ir and any of the sensors of the TSOP series. You will get good range and your readings will not be affected by ambient light
Title: Re: other circuits for distance measurement
Post by: superchiku on March 20, 2008, 12:36:04 AM
TSOP cant be used for distance measurement or is it ? i think they are only used in remotes

if u have any schematic for distance measurement then plzz do post it here
Title: Re: other circuits for distance measurement
Post by: Ro-Bot-X on March 20, 2008, 12:47:12 AM
Check out the Parallax BoeBot manual. You will find out how can a sensor like TSOP (they are using a similar sensor made by Panasonic) can be used to find range. The same method I was talking about in my previous message.
Title: Re: other circuits for distance measurement
Post by: superchiku on March 20, 2008, 01:20:45 AM
ill check it out then
Title: Re: other circuits for distance measurement
Post by: Steel_monkey on March 20, 2008, 03:52:40 PM
TSOP "measurements" are highly affected with color of an obstacle, so black chair will be seen much closer than white fridge door. Freequency sweep will help, but IR receiver works more statistical then linear- at the boundary of sensivity ( object is far ) it will not just stop working, it will rarely "blink" ( I say so because I monitore it's output with LED), so statistical data processing is required for proper analisys. I personally would prefer sonar  ;D 
Title: Re: other circuits for distance measurement
Post by: superchiku on March 20, 2008, 10:29:55 PM
ill go with ir coz sonar is costly :(
Title: Re: other circuits for distance measurement
Post by: Steel_monkey on March 21, 2008, 03:11:39 PM
I think, nobody stops you from making it yourself.
Title: Re: other circuits for distance measurement
Post by: superchiku on March 21, 2008, 11:08:45 PM
well i did some reserach TSOP isnt taht much trustworthy it wont be able to differentiate colors so i have to get a sharp ir for best results