Lobster Bath Alarm

2025-12-29

Or: How to Put Way Too Much Effort into Something Frivolous

Rob and I bought a home together in the spring, and among many other nice features, it came with a Jacuzzi tub in one of the bathrooms. I like the occasional bath and I've used it a few times, but Rob took a strong liking to it and uses it much more frequently than I do.

One of the downsides of taking a bath is that it takes so long to draw the water for it, and many months ago Rob said in a passing comment that it would be nice if there was some sort of alarm that detected when the bathtub was full, so that he didn't have to constantly check back or rely on a timer that was unreliable due to fluctuating water flow rates. Well, we have some water leak detectors in a few strategic locations around the house, which let out an obnoxiously loud alarm should they ever touch water, so I figured that such a device with a less annoying noise must exist. After searching the web for a few minutes, I didn't find anything compelling; everything I found let out some variation of loud beeping, which runs counter to the relaxing vibe that one wants before soaking in hot water.

The two of us have a long history of making things for each other as gifts, so when I was thinking about what to make him for Christmas this year, I thought of that offhand statement a few months back and my brief failed search. Why not just make him a alarm that went off when the bathtub was nearly full, and wasn't obnoxious?

I was very into hobby electronics as a kid. For some reason, this is a penchant that runs back numerous generations along my paternal line, pretty much back to when electric power became available to my ancestors in Shanghai in the late 1800s. I remember that at some point in late elementary school, my dad came home with of those 100-in-1 electronic project kits with a bunch of components that you could attach together via springs and wires, and I was immediately enraptured, spending pretty much an entire summer working through every single project from the first blinking LED all the way through to a basic piano that played a scale. From there, I rapidly graduated to a breadboard and a little pile of electronic components from RadioShack, learning the language of resistors and capacitors and basic circuit physics. By high school, I had a whole little station permanently set up at my desk with a soldering iron, helping hands with a magnifying glass, and so on. The AM/FM radio I made the summer before senior year still hangs in a bedroom in my parents' home today.

The basic proficiency with electronics I gained from all of those projects has certainly paid off in my adulthood. Any wiring work that I ever have to do in a house is no problem; even if I don't immediately understand what's going on, I know that I can figure it out without too much trouble if I just draw out the circuit diagram. With a multimeter and soldering iron, I've diagnosed and fixed the broken control panels of aging home appliances like dryers and vacuums, and rewired and resurrected old power tools that had languished in disrepair for decades. But actually tinkering with hobby electronics for hobby's sake had fallen by the wayside as I pursued other interests.

Anyways, I digress. I wanted to make a nice alarm that was triggered based on water level. I have worked as a corporate software engineer worker bee for over a decade, and with that experience comes a fair amount of exposure to product design and user experience that has rubbed off on me, so I started off by defining the requirements. The bath alarm should:

Okay, cool. From here, I could work backwards.

I figured the most important part of this alarm was some sort of component with a speaker that I could load an audio file onto. I quickly found that these are sold online for cheap, so I ordered one. It was more advanced than I needed it to be, but I figured the parts of it that mattered for my budding project were:

The core audio component.

At this point, I ran into my first minor hurdle. The Amazon page said that the component was compatible with MacOS, but when I tried plugging it into my laptop, my laptop charged the component but failed to recognize it as a storage device. Looking at the reviews, I saw that other people had run into this issue and stated that it was only usable with Windows before Windows 11. By some stroke of luck, I just happened to have an extremely old MacBook lying around that I had installed Windows onto many years ago, in order to play games that were only offered on Windows. When I plugged it into this laptop, it worked, and I saw that I was able to load mp3 files onto the device, and additionally configure it so that a song played when the provided switch was pressed, and stopped when the provided switch was released. Furthermore, the provided speaker seemed decently loud.

This was pretty much the core functionality, so at this point I breathed a little sigh of relief. Little did I know that there would be a number of further hoops to jump through before I had a device that I was happy with and felt I could present as a Christmas present.

With the audio component working at a basic level, I now had to make it trigger through water. I cut the provided switch off and verified that by simply touching the two wires together that had previously gone to the switch, a song would play, and that when I removed contact, the song stopped. It was at this point that I learned an extremely basic physical fact that had somehow eluded me my whole life. I, like everybody else, grew watching movies and shows where people got electrocuted through water. So, I naively assumed that water could complete a circuit, which, with the low voltage of the battery, would not pose any real risk to a human being if they were to also make contact with the water. Much to my dismay, I dipped my two wire ends into a cup of water, and instead of a song playing, absolutely nothing happened. It turns out that pure water has high resistance! It made perfect sense when I thought about it a little more: there are very few ions in pure water. Maybe if Rob added lots of epsom salts to his bath like he sometimes did, it would be sufficient, but I didn't want to assume that this would always happen. So I had to figure out another way to make a circuit close when water rose.

After a bit more searching, I discovered the existence of a switch used in plumbing systems, with a piece that would float up and close a circuit if fully submerged in water. I ordered the float switch and tested it when it arrived; it worked but felt like it had the potential to be a little flaky, so I decided that I would wire in two in parallel, making it so that if either one floated up then the alarm would trigger.

Next, I stepped back and thought about the requirements I had set out for myself again. Unfortunately, the on/off switch on the audio component was tiny to the point of being unusably inconvenient, and also didn't indicate whether it was on, if the song switch wasn't also triggered. To address this, I decided that I would buy a larger switch with an LED, splice it in right at the battery, and leave the audio component's tiny switch permanently on. This was another part I could order for cheap online, and with a little bit of rewiring and soldering I had it in place as well. It felt like I was nearing the end: it was a mess of wires, but I had a device that would play a song when I submerged part of it in water, and could also turn on and off easily with a huge button that also had a power indicator.

I couldn't present my husband with a mess of wires, so I had to find housing for all of it. For some reason, what came to mind was a hollow plastic cartoonish frog bath toy that I could stick everything into; I must have had one as a kid or something. However, a search both physically in a store and online didn't reveal one that I was aesthetically happy with. Instead, I opted for a hollow plastic lobster. With this choice, the song for the alarm followed naturally: the lobster would sing "Rock Lobster" by the B-52's.

Lobster surgery in progress.

I also still had to figure out how to make the alarm easy to place. I wanted Rob to be able to just hang it on the side of the bathtub, with the float switches set at the optimal bath level. I didn't have an immediate solution to this that I was happy with, but as is often the case with these things, my brain worked on the problem subconsciously and I realized as a shower thought the next day that a custom PVC frame was easy to construct to exactly the correct dimensions, and would solve the problem entirely. So the next day, I went to the hardware store and came home with a pile of PVC pipe and joints.

It ended up taking a bit more trial and error than I anticipated to get the PVC frame right, but it ultimately wasn't too painful. Mounting the float switches on two caps that went through the frame to the lobster's mount point wasn't bad either. What did suck, however, was installing all of the electronics inside the lobster. I put the speaker in the right claw, the switch on the head, and the USB-C cord going out of the tail, but the body cavity was a little smaller than ideal, and it took a lot of really careful finagling (and honestly a lot of just crossing my fingers that I wouldn't break a component or connection in the process) to get all of the wiring into the lobster. I did manage to get it all in, and I was almost done. Right?

It was on this supposedly final evening of working on this project that Rob serendipitously decided to take a bath. My workspace was right next to the bathroom containing the bathtub, and when he turned on the water on and walked away, I realized that the water was loud. Really, really loud. Like, probably drown-out-the-alarm-speaker-on-max-volume loud. Indeed, I ran in to test it out real quick and I couldn't hear the song over the sound of the water filling up the bathtub at all. Shit! Christmas was just around the corner due to multple rounds of shipping for all of the project components, and here I had a bath alarm with the extremely fatal flaw of being completely inaudible while the bathtub was filling! I was completely despondent and felt like just scrapping the whole thing, but I told myself I would sleep on it and see how I felt about it the next morning.

Well, the next morning (Christmas Eve) came around, and while my initial despair and frustration had subsided, I was still disappointed about the whole project. I felt I had to obtain, wire in, and test out a more powerful speaker, which had unclear compatibility with the audio component, whose speaker specified an 8 ohm resistance with a 1 watt power draw. Was there anything I could do with the speaker that I had and that I knew worked?

Pacing around the house, I looked up and saw a component of the house that I had paid almost no attention to until that moment: a box on the living room wall near the ceiling, which housed the alarm component of an obsolete home security system. My mind grabbed onto this and started racing. This box was one room away from the bathroom. There was likely already wiring going to this alarm somewhere that I could repurpose. There was a cabinet in the bathroom, literally right next to the bathtub, that I could hide wires in. Could I hide my alarm speaker inside this old speaker box, wire it through the bathroom cabinet, and figure out how to make it easy to connect to the lobster when needed?

First things first, I learned from my previous mistake and immediately tested the concept out by shooing Rob out of the house, putting my whole existing lobster on the wall near the speaker box, and triggering the song. Indeed, the nautical tones of "Rock Lobster" sounded clearly throughout the kitchen and living room, into the main bedroom, even when I had the kitchen sink running and the living room speaker separately playing a song at reasonable volume. This crazy workaround just might work!

The biggest question mark in my mind after this was how to connect the lobster to a wire that emerged into the bathroom cabinet, using a component that I could run out and buy locally, because I had one day before Christmas. It had to be easy to use: in my mind, this was non-negotiable. I didn't want Rob to have to literally be twisting wires together to use the alarm every time, because if I were in his position I'd likely find it too onerous and just not use it at all. The solution to this was a 2-pin trailer connector that I could buy at my local auto parts shop. These were designed to be easy to plug and unplug; I simply had to chop it in half, connect one half to the lobster, and connect the other half to my speaker wiring.

Finding the existing wire going to the obsolete speaker and wiring it invisibly into the bathroom cabinet ended up being a whole complicated side quest involving attic hijinks and crochet hooks, which took a few hours, and I won't get into the details here. But in the end, I did get the correct wire through into the bathroom cabinet, and I wired up one half of the connector and made it easy to pull out and connect, and store. I got the new speaker wired into the obsolete box, completely invisible. I got the lobster rewired and repackaged with the new connector also coming out of its tail, and I filled in the hole where the speaker had been with a little love note. Most importantly, I managed to keep Rob in the dark the entire time by forbidding him from being in various wings of the house at various times.

I didn't have time to actually test out the final product in full, because at the time there was simply no way to do so without spoiling the whole thing. I only knew in theory through my multimeter tests that all the connections were good. But, I hid away the bathroom wiring, packaged up the lobster, and put it under the tree.

Watching Rob unwrap the lobster was priceless. He's extremely intelligent and good at figuring things out, so I asked him to take a stab at figuring out what the hell this lobster with a switch on a PVC frame was supposed to do. He immediately saw that it was supposed to connect to something and further surmised that it looked like it was supposed to mount on something. He actually gravitated into the bathroom and stared at the bathtub, but gave up on it because he couldn't see what it might possibly connect to there, all of which I was pleased with. Shortly after that, I revealed that his bathroom suspicions were correct, plunked the lobster down on the bathtub edge, and smoothly pulled out the hidden wire and connected it to the lobster.


The finished lobster.

At this point, he realized it was a bath alarm but still had no idea where the actual alarm was. I didn't want to actually fill up the bathtub right then and there, so I put the connected lobster in the bathroom sink, turned on the water, said "This better fucking work!", and directed us back into the living room.

Lo and behold, much to my utter relief and his utter confusion, about 10 seconds later, we heard the opening riff of "Rock Lobster". I got a lot of joy out of watching him triangulate the source of the music and realizing where it was coming from: an obsolete home component that we had talked about removing in passing when we first moved in, and then completely forgotten.

And so, my husband now has a whimsical little gadget that will marginally improve his quality of life once or twice a month. Was this necessary? Absolutely not. He could have kept on setting repeated timers and life would have been just fine. From a pure labor standpoint, the total amount of time that he saves in not setting alarms will perhaps never sum to more than the amount of time that I put into inventing the lobster bath alarm. But I don't think that matters at all.

For me, this was the first creative project I've done in a very long time that was pretty much just hobby for hobby's sake, and not because I had to do it for some other reason. My personal life has been an absolute doozy these past few years and I spent a lot of 2025 feeling burned out, which manifested in a pretty extreme lack of motivation with personal endeavors, and a fair amount of crying from sheer mental exhaustion. I recognized this early on (unfortunately, this is not first time life has put me through the wringer) and placed a lot of emphasis on therapy and self-care, which I think were invaluable, but I also think recovering from burnout necessarily just takes time.

To me, the lobster bath alarm represents recovery. I found joy in making something for the hell of it again. I felt the frustration of running into repeated obstacles, and I felt the satisfaction of figuring out creative but solid workarounds, ultimately ending up with something that I find much cooler than what I had originally envisioned. I felt the desire, with this blog post, to write and share my thoughts again. Moreover, I thought this project drew from a wide variety of knowledge that I've been picking up since I was a kid: electronics, software, product management, and even some of the home improvement and plumbing skills I now have. It feels very much like me, and I felt like myself again doing it, and I'm very happy about that.

Mid-project component explosion.