HI James and everyone, thanks for the prompt reply. I am using both sonar and IR for my collision detection. Is it advisable to have sonar sensor as its only form of detection?? Anyway, do u know what the photodiode reacts to?? Normal light or IR?? It is an important point for me. ----- Original Message ----- From: "James Burkart" To: Sent: Wednesday, December 27, 2000 4:37 PM Subject: Re: [OT] Sound Detector > 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 > > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu