Sounds almost perfect to what I need, except for one thing. They state, "As the microwave radiation penetrates many materials, such as plastics and ceramics which are opaque to light, the sensor modules can for many applications be located hidden from view. ". This is great for human presence detection in automatic door opener applications, but I have no way of telling what kind materials will come in front of the sensor system. Have you tested it with many objects and surfaces? What kind of results do you get? What are you using it for? Thanks. Sebastian >-----Original Message----- >From: Gordon Varney [SMTP:varney@CLAS.NET] >Sent: Wednesday, August 25, 1999 4:15 PM >To: PICLIST@MITVMA.MIT.EDU >Subject: Re: Signal filtering through code > >If you want something different, I don't know your cost restrictions, but >for $25.00 each and $18.00 in small qty. Siemens offers a 2.4 GHz Doppler >radar sensor, with antenna built in. (Part number KMY 24) A complete sensor >that will determine distance and direction by monitoring 2 sensor outputs >with your A/D microcontroller. Up to 15 feet possible,and very small in >size. (1.125"x1.5"x.375" approx.) I use them there are great. The Marshal >distributor in Kansas City MO. has stock. > >Gordon Varney > > >----- Original Message ----- >From: Dwornik, Sebastian >To: >Sent: Wednesday, August 25, 1999 1:08 PM >Subject: Signal filtering through code > > >> My current robotics project requires me to design and build an accurate >> and stable IR proximity detection sensor system. It should give feedback >> of objects up to 5 feet. My chosen tools are the PIC16F84, the >> LTC1298 12-bit ADC, and the VTR24F1 optosensor from EG&G. >> The sensor simply contains an IR LED and a photodarlington in a single >> package. >> >> My current solution involves simple noise filtering through code. The >> opto proximity method is through the use of intensity or signal >> strength, >> reflected off an object. >> >> Algorithm: >> Pulse HIGH! ; LED ON. >> Read ADC ; Result A = Signal + Noise >> >> Pulse LOW! ; LED OFF. >> Read ADC ; Result B = Noise >> >> SUB A-B ; Result C = (Signal+Noise) - (Noise) >> >> C = pure signal strength. >> >> This has proven to work well for distances up to 8 inches using an 8-bit >> ADC. This is the first time I'm trying to extend the range, with a more >> sensitive sensor and a 12-bit ADC. >> >> Is there a better algorithm of filtering which would provide greater >> results? A better sensor, or maybe a better method to the entire >> project. I have played with Sharps' GP2D02 module as well; and have >> gotten rather unsatisfactory results. If the current method cannot be >> improved upon, then my next step is to try one of those 40 khz >> Sharp IR modules. They won't give me proximity ranging, but >> maybe reliable object detection; and atleast that's a start. >> >> >> Sebastian