A computer mouse unexpectedly became wet during the night.
A computer mouse unexpectedly became wet during the night.
I woke up this morning and found my Logitech M705 mouse on the kitchen counter where I had left it. I picked it up and set it on the table for later use. When I sat down to operate it, it was sitting in a water puddle shaped like a mouse. There was no water on the counter, and the table wasn’t wet when I placed the mouse down.
Before going to bed, I turned off the mouse using the switch beneath it and placed it on the kitchen counter as usual. I avoid leaving it on the table because of my cat, and I don’t want to search for it on the floor in the morning (good boy stays off the counter).
The mouse turned on fine and clicked the right-click button without any issues. However, tracking was affected due to water inside. The batteries are 2 Energizer AA alkaline cells. They were intact and working properly, but there was a small amount of water inside the compartment (on the underside). After drying out, the mouse is fully functional again.
The mystery remains: how did water end up inside the mouse overnight?
As mentioned, it wasn’t powered on, and the switch was off. Also, I live in the Arizona desert, where humidity stays around 18% even with the humidifier running. It rarely exceeds 50% even at night. Any ideas or explanations are welcome.
How much water is there?
Is anyone else in the house apart from the cat?
Does the cat land on the table?
If the counter was chilly, then the base of the mouse would probably be cool too.
After the mouse was put on the table, any dampness close by would probably have condensed beneath it.
It seems it might have been around four tablespoons of something. I’m living alone. The cat likes the table but not the counter where the mouse was. Both the counter and the mouse were cool. The humidity was low to normal most of the time (perhaps around 25% when I went to bed), which is why moisture could form under the mouse like that. This has never happened before, and I always put the mouse in the same spot each night.
I don't really understand.
4 tablespoons seem like a lot of water. Maybe just a few teaspoons?
My curiosity won over me.
A small but practical test here gave me about a 3-diameter circle of water using one tablespoon on my counter. It was roughly the size of my mouse—Logictech M310.
A teaspoon poured out into an oval shape measuring about 2" by 3".
And a bigger point: you can be sure it's water, not cat pee. You'd probably tell if that was true, especially since the mouse would have been wet on top. Still, I'm curious.
What I can do is try to stick to your usual routine and see if it repeats.
It wasn't a precise measurement, but the water began to spill off the table when I lifted the mouse (the table isn't completely flat). There was more still inside. The mouse surface was dry and odorless—no signs of cat pee or any liquid dripping from above. From now on, I'll store it in a Ziploc bag at night.
Check out more about Gremlins – not only the films.
Keep the guesses to others.
A sprinkle of rice here, a dash there.
Wow I've never, ever seen this this bad before. To drive condensate in a manner to cause this you'd have to remove the mouse from a freezer and put it on the bench in a high humidity environment, or use it right after, heavily, and then shelf it. There's no water in an alkaline battery that could leak even when corroded, and even with the most extreme temperature and condensing humidity conditions I cannot imagine the mouse could require enough thermal energy to *not* match the environment temp within half an hour or so driving minimal condensation. I've got an M325 and an M280 - never had this issue...there is no source of moisture within a mouse.
However.....
Depending on the operating conditions prior to you placing the mouse on the bench, it's possible that evaporated sweat and and non-sweat moisture exuded from the skin has condensed inside the mouse during operation - in volume - and had run out on the bench overnight.
I have in the past had a mouse that got wet inside - not enough moisture to run out, but enough for a film of condensate to coat interior surfaces, the bottom of the mouse, and the desktop immediately around it. Had I not noted it and dismantled/cleaned out the mouse it might have come together and run out the bottom. This was caused by an extended period of operation during a system implementation done in a very cool airconditioned office but with a nervous and frantic implementer using my mouse (me). So the mouse was cool enough to condense out the moisture from my hand and accumulate it inside the mouse but not in volume on the desktop (the hint for me was a patch of misty condensate around where my hand was resting on the desk). If you are confident the cat didn't decide your mouse is a good litter tray, and with utter conviction you can conclude there is just no other physical way moisture got to the mouse such as dripping from above or being used in a condensation pool from a drinking glass (water will wick upwards through the case joins) - it will be condensate. Deductive reasoning can apply here with success. Therefore if on the same night you placed the mouse in a ziplock - you still would likely have woken to water in the bag. Smaller mice like Logitech wireless ones tend to drive the operator to use the mouse with fingertips rather than cupping the body of the mouse like with a full size mouse. Cupping the body would increase it's temp pretty quickly, but driving it "palm off" would mean the mouse body stayed pretty cool (close to the ambient temp) and would be the first nice place for airborne moisture from your hand to condense.
My conclusion without personally examining the scene and mouse - condensation!
EDIT: I just re-read your post and noted your location in AZ. Temperature swings even with low RH% and human hands will definitely cause condensation in places you might not expect. So I'm about 10% more confident in the condensation root cause, with the moisture source being your otherwise dry hand. As I type, there are two small patches of consolidated moisture droplets on the palm rest of my laptop. Indoor temp is currently 19 degrees celsius and RH is 38%, the laptop palm rest is probably 3-4 degrees above ambient - but still I have this condensate. It evaporates rapidly if I remove my hands but that would not be the case if the moisture was accumulating inside an enclosure.