Footstep Sensing ( Like Floor Piano Keys ) ? - Page 1
Forum section: electronics / projects

author: David_AVD
author_rank: Super Contributor
timestamp: June 09, 2015, 03:06:55 am
content: Has anyone done a project where you detected someone standing in a zone like the floor piano in the movie "Big" ?Each detection zone is to be around 350mm x 800mm and there will probably be 8 or so zones all in a line along a hallway of sorts.I've tried old school (alarm) floor mats, but they really don't give a reliable step on/off output and the available sizes are limited.Overhead sensing via a camera won't work as people may choose to jump over an area and not activate it.Another idea is a piezo disc on the underside of each step, but this would only detect the transitions, not the steady state of someone standing on it. That *may* be acceptable if I can reliably differentiate between the on and off steps.Lastly, strain gauges seem usable but I am concerned about the cost of the signal processing and how far it can be away from the strain gauge.Any ideas or comments?

author: Richard Crowley
author_rank: Super Contributor
timestamp: June 09, 2015, 03:32:40 am
content: What is the physical nature of the "zone" Can it be a "sprung" surface so you can put one or more mechanical switches under it to detect pressure of more than x kilograms? Note that many of these kinds of things (like the one in the movie) are illuminated from behind, so there is plenty of space for mechanical switches, strain gauges, or whatever.Or are you talking about something very thin like a giant version of a resistive touch-pad that can overlay an existing floor, stair-tread, etc. Those are also commercially available. They can be hidden under carpet, etc.

author: Corporate666
author_rank: Unknown
timestamp: June 09, 2015, 03:33:24 am
content: I did a floor that had squares all over it and each one was pressure sensitive.In this case, the panels were translucent so optical was the simplest and cheapest. The other idea was switches on each panel, but this required a raised floor and somewhat-carefully engineered support structure to actuate the switch upon foot traffic. Load cells are another way - the cheap ones used in digital scales can be had for a few bucks, but again you need to consider a mechanism where foot presses actuate the sensor.

author: abebarker
author_rank: Contributor
timestamp: June 09, 2015, 04:08:03 am
content: How about capacitive sensing. Aluminum foil underneath carpet, perhaps. There are several different geometries and sense methods that can be used.Here is a link to one of the simplest method I could find;http://playground.arduino.cc/Main/CapacitiveSensor?from=Main.CapSense

author: David_AVD
author_rank: Super Contributor
timestamp: June 09, 2015, 05:10:47 am
content: All good questions and suggestions guys.I believe the existing floor surface is carpet over concrete (or maybe wood). I think the idea is for the existing carpet to have rectangles cut out and replaced with another colour to indicate the zones.It's quite likely that they will use low profile metal strips where the old and new carpet joins. There is a small possibility of raising the zones, but that may pose a trip hazard.Raising the whole hallway up by 50mm would be better as that would allow room for cables / electronics / better detection hardware.I'm going to cut out a piece of 5mm acrylic to see how much deflection that has. Ideally it should trigger when a child steps on but withstand patrons on the heavier side too.

author: savril
author_rank: Regular Contributor
timestamp: June 09, 2015, 11:19:23 am
content: Is this this that you are trying to achieve ? :http://greenismything.com/2012/09/19/just-for-fun-the-piezoelectric-slide-electricity-on-the-dance-floor/A french article on Toulouse street floor that power public lighting :http://ecologie.blog.lemonde.fr/2010/04/14/a-toulouse-un-trottoir-produit-de-lelectricite/Those floor are made in Netherlands by Jaap Van Der Braak (Sustainable Dance Floor).

author: David_AVD
author_rank: Super Contributor
timestamp: June 09, 2015, 09:12:12 pm
content: No, I simply need to sense when people step on and off (as separate events) each zone.There's no illumination of the zone and no power reclamation going on.Sorry I can't talk about the exact end use due to an NDA in effect.

author: abebarker
author_rank: Contributor
timestamp: June 10, 2015, 07:13:52 am
content: I think this is much like you are looking for;http://www.future-shape.com/en/technologies/23QuoteMany microcontrollers have capacitive proximity/touch sensors built in to them but there are also dedicated chips that serve only that function. There are hundreds of chips that can be used.For example, here is one of the cheapest from mouser;http://www.mouser.com/ProductDetail/Azoteq/IQS127D-00000TSR/?qs=sGAEpiMZZMsVh0scArXy33KTkQUiErW7jN7yguCr1UQ%3dHere is a video of another being used;