remote sensor project

bpcwhite

Hello All,

I am working on a project for a biology class and need to setup a remote motion sensor that basically records the time that motion was sent. I am still going through the basic parallax tutorials, but I'm trying to plan ahead on what I'm going to need as far as a circuit to setup. I've figured that there are two ways to do it. One way is to have RF transmitters on each of the motion sensors, and those send data back to the main parallax unit (hopefully I could do this without having a parallax microcontroller at each remote sensor). Also, I could use the USB memory stick data logger attached to the motion sensors, but I believe each datalogger requires a parallax unit directly connected to it. I am really trying to keep the cost down as I won't have a very high budget. Worst case scenario I can have cables running directly from the motion sensors to the parallax unit, but then I'll have issues with distances of cables, as my distances need to be between 10 to 15 meters. Also, this is in the field if I can do it without cables that would really be the best.

Any tips on how I should go about this project? What method is better, usb datalogger or RF transmitter?

Thanks,
Bryan

LoopyByteloose

Wikipedia 'networks' as the project as you approach it is about designing an appropriate network. Wires are not only cheaper, but less prone to problems of interferance. The more hardware you buy, the more the whole thing costs. Instead, see if you can time network communications to no require local storage of lots of data. The BS will store a few bytes in a buffer.

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Ain't gadetry a wonderful thing?

aka G. Herzog [noparse][[/noparse] 黃鶴 ] in Taiwan

Larry~

You did not give all the info needed will these be different rooms or not.
if not, you may with the right unit, get 30 feet distance mounting them back to back you could get 50-60 feet and the stamp could be in the same box.

bpcwhite

Hi, thanks for the replies.

The motion sensors will actually be outside, and possibly obstructed by shrubs or trees, therefore anything that requires line of site is probably a bad idea. (So I'm leaning towards wired.)

Larry, when you say those distances are you talking about these things being connected by wires, or RF transmitters? And I'm not sure by what you mean the stamp could be in same box? Do you mean at each sensor there would be a STAMP? Or you are saying wire them in series with STAMPS in the series to extend the range. If so, that's not necessary as I will be placing them in a circle around the STAMP so that each center is equidistant from the central unit.

Loopy, it seems like you are saying that it would be most effecient to have the motion sensor just send a signal back to the BS as soon as it picked up a signal, and then have it go into a buffer (since there will be multiple sensors). I wonder if there is any way to have a large buffer, or if I can set up the sensors so they somehow won't overload the BS buffer?

Thanks,
Bryan

Larry~

here are some pictures of the one I made 12 years ago. This was version one prototype using an old alarm sensor.
Version two the serial port not only was used for download of info time,date,temp, but was hooked to a serial digital camera and took pictures,
And the new pir sensor was going to make this a lot smaller.

all the cameras switched to usb, usb·protocols were hard to come by back then, things just started moving too fast for me to keep up.

Larry~

They would use one stamp have two pir's and be read using more that one pin each one could see 25 feet so from the center they could reach 50 feet. but now that we know there will be obstructions scratch that.

Are they going to stay in one place always, or will they need to be moved to other locations someday?

bpcwhite said...
Hi, thanks for the replies.

The motion sensors will actually be outside, and possibly obstructed by shrubs or trees, therefore anything that requires line of site is probably a bad idea. (So I'm leaning towards wired.)

Larry, when you say those distances are you talking about these things being connected by wires, or RF transmitters? And I'm not sure by what you mean the stamp could be in same box? Do you mean at each sensor there would be a STAMP? Or you are saying wire them in series with STAMPS in the series to extend the range. If so, that's not necessary as I will be placing them in a circle around the STAMP so that each center is equidistant from the central unit.

Loopy, it seems like you are saying that it would be most effecient to have the motion sensor just send a signal back to the BS as soon as it picked up a signal, and then have it go into a buffer (since there will be multiple sensors). I wonder if there is any way to have a large buffer, or if I can set up the sensors so they somehow won't overload the BS buffer?

Thanks,
Bryan

Larry~

Here is an excel graph of some test data I think it was the Fox den·below the house

Larry~

Now don't ask too many questions it took me 45 minutes just to find this thing.
it was made with a pic chip but the testing was done using the BS2

bpcwhite

I appreciate you taking the time to show me your project. That's really cool that you used this in a fox den to see what times they were active. That's actually really close to what I'm going to be using this for. To answer your quetsion, yes I would be using this at different sites (setting it up and taking it down). Also I attached an image of how I plan to setup the sensors in proximity to each other. I'd like to have at least 3 sensors per 1 BS.

Thanks,
Bryan

Larry~

I would not use RF, each RF sensor would cost almost as much as a BS chip. By making them as individual modules you will have more control over placement and downloading. If you need one unit at some other site you can still monitor the old site as well. Maybe to cut costs you could use BS1 but I used a 1302 clock chip and I don’t know if the BS1 talks 1302. If wires work and will not get tangled up in your subjects then go for it.