I was actually at the arduino meetup group, I’m Sorry I didn’t meet
you and didn’t manage to talk with you about this.
I work in testing and developing electronic products and one of the
items I have tested in the past for shops is something called a
footfall device. Its a people sensor! Its actually a calibrated
scale hidden under the welcome mat which weighs people as they step
onto the mat. The weight is stored and from that an average
calculation of the number of people who come into the shop is
achieved. Most shops, supermarkets and football stadia use a similar
system. Infra red PIR sensing is possible and might work but it can
easily be affected by external things and not necessarily people (it
can be affected by sunlight, TV remotes, mirrors etc). You can
actually fool an infra-red sensor with a piece of cardboard!
This is the thing about electronics and engineering in general - there
are several ways to achieve the same thing. So lets break the issue
down and then try and work out where we would begin in trying to
design a solution to your problem:
- How much money do you have to spend? If the budget is tight then
it rules out multiple sensors and some off the shelf kit which might
speed things up. I call this Budget!
- Which sort of sensor do you want to use? Infra red LED laser,
Passive Infra Red Sensor (PIR) like those used with house alarms,
weight, ultra-sonic…there are plenty of different ways of achieving
this. - I call these the inputs
- Which micro-controller do you want to use? I’m guessing you would
like to use the Arduino as you have some familiarity with that. This
is what I call the processing.
- How do you want to display the information? How do you want to
show how many people have come into the shop? - Calculator display
(16x2 LCD) or Seven Segment LED display (back to the future style
digits!), output via bluetooth or wireless or ethernet to a PC (or
Raspberry PI…hint hint)…These are what I call the outputs.
- How much time do you have to make it? Months, weeks, years…Set
a time and then you have something to work to.
Once you have answers to these questions then the real fun can begin -
If you wouldn’t mind email back with the answers so we can discuss further,
AlexOn 20 August 2012 22:04, Biscuitnapper email@example.com wrote:
Firstly, I have to come clean. I am an utter ignoramus when it comes to
actually making things but I really want to start working on practical
projects. At the moment, I volunteer at my local Oxfam and our main problem
is security. We lose quite a few donations to thieves but we can’t really
afford to set up CCTV in our shop. That aside, we would also like to get
quantitative data about our customers - how many come in on average, how
long they stay etc. - which will be really helpful when we redesign our
Now somehow I suspect developing a fully fledged face recognition system is
a bit beyond me at the moment, so I was hoping to start with something
small, like installing a system we could use to find out how many people
come into our shop. I discussed it a bit at the Arduino meetup and the
simplest idea involved an infra red LED and a beam splitter/lens set up that
would divide and focus the beam onto two photo-transistors. If the
photo-transistors were connected with an arduino, then we could use the
disruption of the beam to drive a motor which would be attached to the
My main question is how do I get started (beyond the sketch stage I mean -
there are quite a few of those!).
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