sensor to detect amount of movement

Hi,

I am looking for a sensor that can detect "amount" of movement, it should be simple. Digital on/off output. Maybe some pulses.. it should have fast response that is, if there is one person in the sensed space and it moves fast it should produce more pulses (or if there is more people in the space). Also, it should have fast response so the signal is ready to detect new movement (even if there is people still in the space) pretty fast few ms.

Cameras are not an option as we need simple data to process. Also, PIR type sensors they don´t produce fast enough response.

Any ideas? Thanks in advance for any help, I know it might be a little bit too demanding..

juanpi said:

Also, PIR type sensors they don´t produce fast enough response.

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Are you talking about a light that turns on when something moves in front of it? I was going to suggest this. Some (or all) work by infra-red.

The ones I've seen have a translucent lens over the sensor. The lens is multi-faceted. A moving object produces changing brightness levels on the sensor (or sensors).

The lens is essential. Without it, the sensors become low-resolution. They get the same light level.

I think the store-bought lights turn on about a second after something moves into its field. You say you want quicker response, however.

I believe you could construct a grid of photosensors (3x3 maybe), and mount a lens over them, and you would have what you need. Monitor volt levels on the sensors. The more objects are moving, the more rapid the voltage changes.

Hi,

First of all thanks for your reply. Yes, I thought of constructing the grid but using standard outdoor (needed for the characteristics of the project) although I would prefer something which is already packed. In fact, I have been researching about some IR array sensors but they usually give out measurements and I would need basic on/off values.

Of course is possible to create discrete values from continuous data in software but I need simple data at the sensor side since that data will then have to be transmitted in a complicated environment.

Anyway, that photo sensor array with a lens could do the job.. good point about the lenses by the way.

Thanks again.