PDA

View Full Version : Building long range IR sensors



counter_struck
03-12-2008, 12:56 PM
Hey

I am a student from South Africa and the required components I need are either not avaliable here, or are too expensive to source overseas. I want to build a long range sensor that can detect up to 2 - 2.5 metres.

It would take too long to build and debug an ultrasonic sensor. I want to build a long range IR sensor. I have researched about robot wars, and a concept of using Infrared detector modules....like those used in TVs was used. Each bot had a receiver....the detector module and a IR LED as a transmitter. The transmitter acted as a beacon and Bots used their detector module to detect other bots. Ranges can reach over 30ft.

I want to use this concept in navigating my bot through a circuit in my universtiy. I want to use a transmiiter and detector pair on either side of the car....to keep the car equidistant from the walls.

Is this a suitable solution to my problem? is there any IR sensor circuit that can do the same range of 2 -2.5m?

docel
03-13-2008, 09:01 PM
This forum is full of solutions for this. Search TSOP1738.

The TSOPxxxx is your cheap and best bet.

But read the datasheet THROUGHLY before you use it :!:
It needs a whole lot of monkey tricks for short distance, though.

docel
03-13-2008, 09:03 PM
This forum is full of solutions for this. Search TSOP1738.

The TSOPxxxx is your cheap and best bet.

But read the datasheet THROUGHLY before you use it :!:
It needs a whole lot of monkey tricks for short distance, though.
The simplest thing is to use the TSOPxxxx with a broken-off TV remote control.......

shreek1123581321
03-22-2008, 08:23 PM
tsop is a solution, but its a digital sensor, so it will only give zero or one. but if you want to drive your car iquidistant from both the walls you need to implement some correction taking algorithm such as PD or PID, and for that you need analog data (in short you want to know whether there is wall or not, and in addition you want to know how far it is!) so for that you need to have analog sensor.
sharp sensor do this job. but long range sharp sensors are expensive and you will have to purchase them from outside.
there is one more possibility if you want to try, the problem with simple IR sensor is that the range is small because the intensity of IR emitter is very low, for its dc current is small. we can increase current (in turn intensity) by giving supply in pulses. in that way we can pass around 1 to 1.2 amp current through the emitter giving haigh intensity( and thats what they do in tv remote controls so it is detected from long range also) but then the received signal will also be in pulses so rectify it. simple. you wpuld also like to put a band pass filter in between to eliminate ambient light effect. by doing this i ve achieved a range of about 1m. but dint try for more distance than that... i guess it should work,...