Emily Velasco's Nev-R-Wet Pee Probe Screams When It Finds a Wet Metro Seat — Just Like You
Not sure if that Metro seat is safe to use? The Nev-R-Wet will let you know — and anyone else in the vicinity, too.
Self-described "arts-and-crafts supervillain" and science writer Emily Velasco has designed a device that takes the stress out of selecting a seat on the Metro — by figuring out whether it's wet with rain or other less savory fluids.
"A friend who commutes to work on the Metro asked if I could make a wand that would scream if pressed against a wet seat pad, so they can tell if a seat is wet without touching it with their own fingers," Velasco explains of the project. "From prototype to finished product in a little over one day."
The resulting device, initially prototyped on perfboard before being assembled into a handy 3D-printed portable cylinder, is the Nev-R-Wet Pee Probe. Its operation is simple: flip the power switch on the side and push the tip of the probe against the seat of your choice. If the seat's damp, a pair of exposed metal probes will have enough continuity between them to complete the circuit — and you, along with everyone else in earshot, will know it.
"A quick demo with a lightly moistened paper towel shows that the Nev-R-Wet Pee Probe sounds an attention-catching scream alarm when it detects damp surface," Velasco explains. "That is what my friend requested!"
The gadget itself is driven by a compact Arduino Nano-compatible microcontroller board, linked to an amplifier, a speaker, and the probes. An internal battery means it's possible to use it on-the-go — and never experience the horror of a wet seat again.
Velasco has detailed the project in this Mastodon thread.