X-band motion sensor clarification
Larry Molter
Posts: 28
I know that there have been some discussions about the output of this sensor. And I think there is still some confusion. So... can I clarify how I think it works? I haven't scoped it yet, so I'm gonna guess a little.
The spec says that it transmits 10us pulses at a nominal frequency of 2KHz, right? What I don't know is what it sends back through the output pin. Will it be a series of pulses at a 2KHz rate with the amount of pulses proportional to the amount of motion (more reflection, more pulses coming back)? Or will it be pulses whose frequency is proportional to the amount of motion (more motion, the closer the pulses)? I have to develop a detector for this but I can't count pulses as you would do with the Basic stamp or the Propeller. For now I just want to know if motion was detected; I don't really care how much. I was thinking about triggering a retriggerable monostable. In this way, I would get a single pulse whose duration was proportional to the amount of motion. Am I off base here?
Of course, once I get the scope (or logic probe) on it, this post is a moot point.
The spec says that it transmits 10us pulses at a nominal frequency of 2KHz, right? What I don't know is what it sends back through the output pin. Will it be a series of pulses at a 2KHz rate with the amount of pulses proportional to the amount of motion (more reflection, more pulses coming back)? Or will it be pulses whose frequency is proportional to the amount of motion (more motion, the closer the pulses)? I have to develop a detector for this but I can't count pulses as you would do with the Basic stamp or the Propeller. For now I just want to know if motion was detected; I don't really care how much. I was thinking about triggering a retriggerable monostable. In this way, I would get a single pulse whose duration was proportional to the amount of motion. Am I off base here?
Of course, once I get the scope (or logic probe) on it, this post is a moot point.