Urinal Splash Danger Meter




Introduction: Urinal Splash Danger Meter

About: Robb was once an Artist-in-Residence at Autodesk's Pier 9. they went to Carnegie Mellon to study Art. they mostly do tangible artifacts that are often complex. they can be reached at www.robb.cc

Here at Instructables HQ on San Francisco's Pier 9, the men's restroom had a problem.

Particular pier peers persist as poor-precision pee-ers. The result of which is photographed above. (Emphasis added).

Solution: Positive-peer pressure for proper peeing posture. The Urinal Spash Danger Meter

A solar powered electric apparatus for displaying pee-stance quality* and correlated splash risk.

The concept is explained in this excellent video.

*Pee-stance qualityis directly proportional to distance from urinal. Closer is always better.

Step 1: Aquire Parts - Begin Tuning

How does it work?

It is deceptively simple. It is just a solar panel and a analog meter. The more light that hits it, the more danger it indicates. The closer a person is to the meter, while properly lit, the less danger it indicates. Being solar, it requires no batteries or plugs.

Meter/Panel Selection

This is a somewhat difficult process. I got lucky and had a bathroom with a strong directional light source directly above the users head. Because of this, a stark shadow is cast on the solar panel which causes the needle to drop. I do not know if there is a good reason to use a ammeter vs a voltmeter, as both increase as light increases. I was more confident in an ammeter as I was getting noisy results on voltage.

  1. Start with a solar panel and a multimeter that can measure amperage.
  2. Measure the current on a panel in a dynamically lit part of the bathroom.
  3. Note the amperage both with bad urinal posture
  4. Buy an ammeter that approximately goes to the high limit

Note that if the difference is smaller than 20 microAmps, you will need to either get a bigger panel or change the lighting in your bathroom. I have not been able to find any analog meters that have precision less than 20 microAmps.

Once you have your parts on hand, hook the panel up to the meter. Red to + and Black to -. You should have immediate response to changing light levels. Find a place on the bathroom wall that works with your parts.

My Parts list:

Note that your parts may differ, as your restroom is non-identical to mine.

  1. Black Acrylic Sheet 0.118 Thick 12 x 12 (We will cut it in a later step)
  2. 50 microAmp Ammeter/Galvanometer (Analog)(eBay)
  3. Small Solar Panel (I used a RadioShack I had on hand)
  4. 3M Dual-Lock

Step 2: Design the New Meter

The μA label is not going to cut it if we want people to know what is going on. Time to make our own!

The finished files are attached, so these steps are only needed if you want to design your own.

Making Template

  1. Take a nice straight-on photo of your meter
  2. Measure the original label width
  3. Bring the photo into Adobe Illustrator or similar and scale it to be the exact size that it is in realit
  4. Put that photo on a background layer and lock it so you don't accidentally move it around or scale it
  5. Optionally, you can print at this stage to ensure your scale is accurate

Designing Gauge Face

In order to make this thing look official and sciencey I decided to use DIN, a nice german font. After a lot of thinking and math, it was determined that the scalar quantity being measured by this solar apparatus is μDroplets/cubit² (microdroplets per square cubit). The meter reads in a exponential fashion, with an asymptote at infinity. Demarcating the danger zone requires testing your panel and your meter ahead of time. I got lucky and had a pretty even spread.

  1. Draw a circle around the pivot point of the needle until it crosses the existing tick marks. (Hold Alt-Shift on the Ellipse tool and drag out)
  2. Open the Stroke menu and increase the stroke width for a thick bar encircling the meter. I used 11pt.
  3. Still in the Stroke menu check Dashed Line. Make the Dash about 8pt and the gap an absurdly large number like 1000pt. This gives a partial arced bar that can be easily resized and colored.
  4. Make the Stroke green and rotate it until it is lined up with zero on the original meter.
  5. Copy the circle, paste-in-place, and repeat for Yellow and Red.
  6. Use the Text on a Path tool to write CLEAR and DANGER
  7. Use the Text on a Path tool to write the numbers for the tick marks.
  8. Add logos and labels
  9. Print it out, trim it with an X-Acto, and see if it fits. Minor adjustments will likely be needed.

Trim and glue

The design can be cut out of regular printer paper and glue-sticked to the old face. Simply force the cover off the gauge and slide the sticky print behind the needle. Once set, reassemble the gauge.

Step 3: Design the Plastic Chassis

The meter needed to be mounted on something. A project box would have worked too, but I wanted something sleeker. There are thousands of ways to do this, and I'd love to see how others solve this problem in the comments.

I decided to use black acrylic plastic(Plexiglas) as it is easy to heat bend and easy to laser cut. Don't have a laser cutter? Don't fret. Simply print the stencil and drill the holes. There are two components and they can pretty much be mounted to anything.

  • Measure the panel
  • Measure the gauge
  • Place the components in Illustrator
  • Add the mounting holes in Illustrator
  • Print a stencil

Step 4: Cut, Bend, Populate Chassis

  • Laser cut the chassis from 1/8" acrylic
  • Carefully bend it along the seams with a heat gun
  • Pop in the meter
  • Double-stick tape the panel to the acrylic
  • Re-connect the wires, Black to -, Red to +

Step 5: Install, and Wash Your Damn Hands

Now that you have a fully tuned and assembled Splashometer, stick it to the wall with the 3M Dual-Lock (Velcro) and wash your damn hands.

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    Getting rid of the urinals and going unigender bathrooms will only cause more angst, as the men will pee all over the toilet seat, and you will hear all the ladies scream.

    It doesn't address the root cause - apathy. If they don't have to clean the floor/walls, why should they care how far away they are or how good their aim? "Put targets in the urinal and light up when they hit it" is a better approach because it encourages focus on the task at hand.


    Reply 7 years ago on Introduction

    I am not sure ungendered restrooms would help, as ladies have a particular trick called "the Stance" in which they hover over a toilet without touching the seat and proceed to spray everything.

    Some of the public bathrooms in Ukraine have a toll; when you go in the bathroom (even the men's room) there is a grouchy lady at a card table collecting about $0.50; if you don't pay you don't use the restroom. When nobody is using the restroom they are supposed to clean it.... doesn't happen though.

    I was at a men's room in a Ukrainian hospital; it was free to use it, but there was a very loud (female) nurse who would check the stall immediately after anyone came out and yell at you if you had "sprinkled", not flushed properly, or left any sort of mess.

    I like the electric shock ideas people are posting here. :-)


    7 years ago on Introduction

    I would add an electric fence wire around the perimeter of the urinal to promote concentration on aiming.

    I've seen a simpler solution.....

    A sign in a public toilet, simply stating:

    "We aim to please,

    You aim too, please"


    7 years ago on Introduction

    Hmmm, I would have used conductive paint to paint a set of varying footprint sizes on the floor, the smaller being closer to the urinal, not that there is any correlation... Terminate each pad to be spliced into the cut end of a spare extension cord which is plugged into a nearby wall.outlet or tapped off the wall mounted megawatt turbo hand dryer. Oh, is there any danger of electrocution?


    7 years ago

    Love the idea. Now just upgraded to a "simple" LED display, add an audible alarm, more power supply options, and adjust for use on a regular household toilet and you can sell them to everyone with a little boy. (And if they learn not to sprinkle from a young age at home maybe we need them in public toilets)


    7 years ago on Introduction

    I imagine this in a night bar bathroom, the splashometer won't handle it :-)