Story is, my university is next to a hospital and last semester they asked us - Illustration students - to propose some form of improvements to the hospital (Art, way finding system etc). Last year I did some electronics for a project, this forum helped me out immensely, so I felt cocky with electronics.

What I proposed was a change to the Hand wash stations. To add LED's above them that give off a little fanfare whenever it's used. I vaguely planned out how it would work, made some after effects videos for it, but basically didn't really wanna be picked. I was and now I have to make it for October. And I'd love any advice for this that I can get.

The initial plan is to use am infrared proximity detector under the station to set it off. Then have 3 16*32 LED matrix displays to light up and say "thank you!". I'm unsure how to power the displays though, hoping an arduino due would be powerful enough? The displays wouldn't need any colour.
Also, I'd like to know if the prox detector needs its own micro controller?

I priced up all the parts I think I'll need to be around £180, the hospital say's they want to bring that cost down. So I was thinking about loosing any precise video, like the words "thanks", and wire up the LEDs myself. But I don't know if that is feasible?

I'd be grateful for any help and advice I can get for this. Also I could link to the video proposals if it would help.

Thanks everyone!

 

any cheap arduino can do that.
Just need one, a prox sensor, led matrix.
prox doesn't need its own micro..
Costs should easily be under $100 USD including enclosure.

There are TONS of tutorials/examples online..
Simply google "arduino proximity led"

 

The link would help.

Hardwiring the "Thanks" message with individual LEDs is feasible, but using the matrix would require a MCP to drive.

The sensor does not necessarily require an MCP, but if you're using the matrix you have one already.

Also, you probably need a timer to keep the display on while the station is in use. That is, once you trigger the message, it stays on long enough to be noticed and read. This can be done with external components, but if you have an MCP…

Do you code? I did something similar with an Arduino (not recommending one here) in a few minutes. Driving the matrix is a little more complicated, but still should be accomplished on an MCP simply.

 

Based on your description, I immediately thought of this. The idea was to encourage people to wash their hands by playing random sounds for fun.

If you're allowed to drop the display, you can easily do with with a sound module and a PIR sensor. Might need a 555 or two depending on how you want to handle the sometimes long ON state of the PIR. Or use something like this with the display.

Might find some inspiration here.

How many of these are you going to make? As djsfantasi mentioned, you could make your own sign by forming 'thank you' with through-hole LED's and a piece of plastic or a box. Then there's no need for microcontroller (uC) and the lack of matrices will bring the final cost down considerably. A timer

If you want to change the message or have it scroll, then using a matrix with a uC is the way to go. I'd suggest using an LED controller between the uC and the matrix as you're talking about a lot of pins. Or use a pre-built panel ready for an Arduino interface. Having a uC detect a signal from a PIR is easy.

If you use LED's, you'll definitely need a wall power supply. Batteries won't last long. If you go with a PIR and sound module only, then a battery option is feasible if wall power is not available.

 

That thing is going to become incredibly annoying very quickly.

 

$11.50 for a sound card. Amazing.

That gets my vote - maybe with a couple of LED's that blink to the sound. I don't know how you would package the switch to the dispenser, but it could be replaced with a cheap proximity sensor.

http://www.ebay.com/itm/HC-SR501-Ad...711?pt=LH_DefaultDomain_0&hash=item5d48b24eff

 

That thing is going to become incredibly annoying very quickly.

+1 I worked in a hospital. Dump the sound idea. That will not only be annoying to the users of the hand washing station, but everyone around it. Hospitals are too noisy as it is. Spend 24 hours in one trying to sleep and you will realize that. Just add a sensor to the automatic (hopefully) faucet and create some kind of countdown timer display, like a string of LEDs, to let the user know that they are doing the full 20 seconds of scrubbing. And make the display ambient-light sensitive. At night, you don't want bright lights when the hall and station lights are dimmed.

Run your ideas by hospital clinical and facilities staff for dealing with the real world issues.

But, it sounds like a good project.

Ken