Well, If you use something like a super-bright blue or white LED the spectrum they emit is very narrow, no IR. But I really don't think that they are bright enough. The light emitted by the "beacon" would ideally be diffused or at least a wider dispersion than the calumniated beam of an LED. The best light source should be an incandescent bulb. They do produce a lot of IR, but the IR LED would be much brighter in comparison. You could also do some things to make the IR sensor less sensative to the "beacon", like a filter of some kind. Have you thought of using some kind of sonar for the collision detector instead of IR? Jameco has a kit that might be able to be adapted. It's the kind of thing that is used in newer cars to let you know if you are too close to something. It would be easier to use "sonar" this way, then to use it to home in on a specific something. James -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Henry Low Sent: Tuesday, December 26, 2000 9:44 PM To: PICLIST@MITVMA.MIT.EDU Subject: Re: [OT] Sound Detector hi james and everyone, I wonder if the strobe light will false trigger my IR sensors and prevent my robot from getting close to it?? Is the strobe light just a normal LED?? I am not too sure how to generate this strobe light. My IR sensor module consists of an IR emitter and a receiver (i am using a photodiode). Isn't the photodiode sensitive also to the strobe light?? or any normal LED shining directly at it?? Hope to hear from you soon. Henry ----- Original Message ----- From: "James Burkart" To: Sent: Saturday, December 23, 2000 1:12 PM Subject: Re: [OT] Sound Detector > What about using a strobe light instead of a sound? Mount two CdS photo > cells facing the same way (eyes for the robot), and put a card between them. > Design a circuit to compare the difference of light levels between the > detectors. When the levels are equal you are facing the strobe. An easy way > to compare the input from the CdS's is to use an op-amp as a comparator. > It's sooo much easier to measure the difference between light levels than it > is to measure sound. I suppose that if you were to stay with the sound > instead of using light you might want to use a similar method to direct your > robot. > > James Burkart > > -----Original Message----- > From: pic microcontroller discussion list > [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Henry Low > Sent: Friday, December 22, 2000 2:54 AM > To: PICLIST@MITVMA.MIT.EDU > Subject: [OT] Sound Detector > > > Hi all, > Seasons Greetings. > I was thinking of implementing beacons in a robot testing arena that > emits sonar signals or a buzzy sound for the robot to move towards. And the > beacon will be turned off upon sensing the robot's presence (which means the > beacon has got it's own sensor too). My aim is to see how fast the robot is > able to disable say 10 beacons in a reasonable robot testing ground. Is this > idea feasible?? How can I make the robot move closer to the buzzy sound (can > be modulated)?? Does it involve a complicated algorithm for it's decision to > move towards the beacon?? Any help, comments are most welcome. > > Regards, > Henry > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu