Motion sensors and graph

Dear all/any,

I am working on a project using a series of screens and digital film cameras and motion sensors. I am interested in having the data from the motion sensors (analogue input) be processed into a graph in a computer. However would like 5 graphs showing the differences between 5 motion sensor arrangements. I am not well versed in arduino yet and am seeking some help coming up with a schematic. I think the code will be the easiest part. But if you disagree and can offer some help, or would like more information on the exactness of this project I would like to hear from you.


well for creating a graph here is a example it also uses analouge sensor so a lot easier :)

My first question is what kind of motion sensors are you talking about? Do you have a link to them? Most I have seen are just digital on/off in nature, they either detect something moving in their detection zone or not. There would be no analog variable value to graph in that case. Perhaps you are considering or using some other more advanced motion detector?


Motion sensors that detect a person walking in between two points.

The set up involves 5 plinths in between two walls in a room, in a line. I would like to have this set up such that when some one walks through any of the spaces between plinths or walls, the motion sensor/s detect this, the data is sent to the arduino which in turn shows it on a graph.

So I think I would need a motion sensor detects a change when a light beam is blocked. I don't know much about motion sensors but Ill do some reading now.

Thank you very much for your replies.

So what are the graphs going to show, as you only have blocked / not blocked information?

Show the how many people go through a given point against time.

Im going to make visual patterns from the data and try extrapolate some kind of statistical regularity (if one exists) concerning crowd dynamics. So this project (or experiment) will be set up in a variety of different places, (we can ignore the cameras and screens for now for they are irrelevant to my question. They will only be using in the exhibition of the project).

I want to explore the uses in deriving mathematical formula from patterns. Of course I could just see some kind of correlation in the graphs but Im currently doing an illustration course, so Im exploring what I can do with images especially. I used to study physics at university, so perhaps you can guess the inspiration for the 'concept'. Also I recently read an article about crowd dynamics which I found fascinating.

Anyway, thats the whole thing and why Im using arduino, seeing as I was rubbish at digital electronics, I am seeking help and suggestions.

where are you going to place the setup ? cause....

So I think I would need a motion sensor detects a change when a light beam is blocked

then if you place it a a crowded place the light beam might be blocked the whole time ;)

Thats fine! Ill try it in all sorts of places, perhaps evn places were there are very few people. Preferaly somewhere where it varies. But the more places the better!

Thats fine!

then you cant do this

Show the how many people go through a given point against time.

Ahh I see! How helpful!

Hmm, well perhaps I will have to choose places carefully then?

Yes to monitor how many people cross a given point you will need to make sure that where sensors are placed more than one person can get through but again i guess it will not be anymore monitor crowd....something ;)

Aye, as has been said - if there's a constant stream of folk close together, the signal will always be blocked, and when they finally pass through, it will record as one person.

One way you could estimate it (albeit crudely) is to time how long it takes for a person to walk past the beam. You can do this yourself by writing a program to add to a counter every millisecond that the counter is blocked. You'd then walk through it a few times at average walking pace, noting the time recorded each time. Take an average of the time taken. Lets say the beam is blocked for 300 ms when one person walks through the beam.

Then maybe you could write a program that has the following condition does the following (the lads on here might better advise on how feasible this is):

if TIME >= 300 ms then set NUMBER_OF_PEOPLE = NUMBER_OF_PEOPLE + (TIME / 300) else set NUMBER_OF_PEOPLE = NUMBER_OF_PEOPLE + 1 end if

So if your person walks through faster than you, it'll record one person. If the signal is blocked for a period of time, it'll divide that time by the time it took you to walk through, giving a rough estimate as to how many people were in the line walking through (assuming they walked in single file). How many corridors are only single file? :-?

Maybe a better way would be to have some sort of sensor on the floor which would add to a counter every time a person stepped on it. This would be ideal on a stairwell as every 2 footsteps would equal 1 person (except those two-at-a-time-bastards).

Another way to go would be to look at foot pressure sensors. You can get these commercially as sensors for bugler alarms and scatter them throughout the space or even under carpets. You can also make your own like I did in this project:-


And yes stairs would be quite good! Also pressure pads, excellent.