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Arduino Project: Interactive Shop Window. Help needed.

herrlichakafool

Hello element14 community!

 

I want to ask for your opinions about an interactive shop window controlled with an Arduino, but first I try to give you an idea about my technical knowledge.

 

Me and my roommate are studying Games Engineering at the Technical University of Munich, and a friend of ours owns a small clothing shop in Munich.

Since we have sucessfully finished an Arduino project before, he asked us if we can create something special for his shop window.

Our knowledge about circuits and Arduinos is between basic and advanced, so i thought it would be great if some more advanced users can help us out a bit.

 

Here is the idea:

 

The shop window will display 8 to 10 wooden racks, each with 3 slots. In these slots we will put in shoes that we want to promote.

 

                         image

 

Every rack has its own IR sensor, and each slot has 2 LED bars. (bottom row green, middle yellow, top red)

Now when a passenger walks past our window, the IR sensors detect the position of where he stands, and illuminates

the shoe rack in front of him up in all 3 colors, while the once left and right are either yellow and green or just green, which

makes an equalizer effect when you walk past it.

 

Now, what we thought was to control the lighting of each slot with transistors, which are controlled by an Arduino Mega.

 

Now our questions to you guys:

 

1. Is it possible to use IR sensors through a glass window? If the answer is yes, how can we locate a passenger correctly without getting

    signals from more than 1 sensor? If it is "no", what other technology can we use?

 

2. Lets say we use two 12V LED strips, what sort of transistors do we need for that? Or is it dependant on more specifications like resistance?

 

3. What problems can occur during our project? We don't have much experience, but we have all the tools needed.

 

 

I hope that someone can give us a helping hand in this, and that my crappy sketch didn't scare you away image

Also thanks to Ben Heck, otherwise i wouldn't know about element14!

 

Sincerely,

Theo

  • Just a couple of comments:

     

    1.  Infrared radiation generally does not pass through ordinary glass.  This is not an absolute and depends chiefly on thickness of the glass and wavelength of the incident IR.  You can do a simple experiment with an Arduino, an IR sensor, a piece of glass and a TV remote. 

     

    2.  What you use to drive the LED strips depends on the CURRENT they draw.  Best bet is to use a DC relay like this one.  Each relay takes 15-20 mA on the drive pin and will pass up to 10A DC through the contacts.  Find out how much current each LED strip draws and search for a relay that works.  This will likely require an external DC power supply to provide power to the LED strips.  Read the specs on the Arduino digital pins to find out how much current they can source and sink.  Generally digital output pins will sink more current than they source.  A digital pin 'sinks' current when it is low, and 'sources' current when it is high. 

     

    3.  I think your biggest problem will be getting the IR sensors to work as you indicate in your diagram.

     

    Kevin H.

  • in reply to kjhart0133

    Thank you Kevin for your quick response.

     

    1 & 3. I already expected that IR sensors are not the right way to do it. Is there an alternative with similar costs? A Kinect won't work too then... image

     

    2. Thank you for your suggestion, i will get myself informed about that.

     

    Anyone with an idea? I hope there is a way without installing hardware outside of the shop to prevent vandalism...

    Maybe some simple webcams could work, but this would require a computer with software running for many hours a day, which is not really energy efficient.

    Microwave sensors could work too (http://www.amazon.com/Wireless-Module-Doppler-Microwave-Motion/dp/B008P683RI/ref=sr_1_6?ie=UTF8&qid=1365694687&sr=8-6&keywords=microwave+radar),

    since they go through glass. They only emit 5mW, which is good, but is it possible to regulate the angle of sensoring by placing metal grids infront of them?

    image

     

    How can i reduce areas where 2 sensors trigger at the same time, or none at all? Is there a type of sensor which detects not only a movement infront, but also the position, and ideally even the distance of the person?

    Or is it more useful to ignore the signal if 2 sensors detect something, until the person walks out of the sensoring area of one of them?

    But if i reduce the blind areas, i also increase the areas with 2 sensors triggering...

    image

  • in reply to herrlichakafool

    Theo

     

    If you mounted your IR sensors inside a metal tube that ran along the top (or the bottom) of the window (outside) you could angle them to reduce the range.

    You could also try mounting a TX that flooded the area and have directional receivers, that would achieve the same.

     

    IR sensors inside mice are modulated at 38KHz, and you may be able to use different frrequencies to help isolate areas.

     

    The vandals wouldn't recognise it as anything but a black tube (IR passes through dark perspex), so it wouldn't be a target.

     

    Sorry Kevin but relays would be a pain.

    Use Mosfets to switch the ground side of the LEDs. (30 by your drawing)

    (This would also allow you to PWM if required which some tricky switching)

    There are some that are optocoupled as well.

     

    I would look at some of the single LEDs and diffusers as an alternative to strips. It will be easier to mount and probably cheaper in the end.

     

    You might want to consider what happens when there is more than 1 person.

    I saw some illuminated steps at a nightclub once, that worked really well when the place was empty....

     

    Mark

  • Hey,

     

    First i try to clear things a bit up image

     

    @Mark: I had the same idea with the IR sensor pipe, it would make things alot easier, but since these sensors have to be placed outside, i first have to ask if we need to drill a hole for the cables.

    I don't think that there is a way to lay the cable without drilling.

     

    We found a suitable sensor for this, which works through glass (http://www.parallax.com/Store/Sensors/ObjectDetection/tabid/176/ProductID/606/List/0/Default.aspx?SortField=ProductName,ProductName)

    The pricing for 10 sensors is a bit high, and it would be alot cheaper if we can use 10 of these (http://www.ebay.com/itm/Microwave-Motion-Sensor-Doppler-Radar-Wireless-Module-/270738971902?pt=DE_Autoteile&hash=item3f094cdcfe)

    and build a circuit for them.

    The downside of these radar sensors is that they only trigger when an object moves, which might cause problems if a person stands still in front of the window.

     

    I will ask around a bit and will update you if we get the informations needed.

  • Okay, here's an outside the box idea for your project.  Put a puppy in the window!  It tracks the people and the sensors track the dog.  No drilling needed.

  • Hey guys,

     

    I like the idea of your project. Looked good in the sketch. So how did it all go in the end? Did you manage to work it out and turn it into practise?

     

    As I'm currently working on a motion sensor for a shop window installation I'm trying to figure out what sensors would work best; ultrasonic (probably doesn't go through glass), Infrared ....etc.

     

    Looking forward to hearing from you. Mattia