Funnily enough I saw an ad for water detecting bed protectors for incontinent people at the hospital just yesterday. They seem to run a material like aluminium foil under the sheet in a pattern. Maybe worth looing into as these seem to fit the bill for what you need.
The ones I saw fit to a system to alert a call centre via the phone if the person wets the bed. I didn't see the price though as no need for one (not yet anyway!).
Or, maybe something like this:
which is 75v, still single phase, water cooled, but it has a recognizable ER8 on it. Costs around $175, delivered.
I'd probably opt to pay more, though, to get something with less runout, like maybe this:
which claims a runout of just 0.004mm, because whatever spindle runout there is will get amplified at the tip of any bit that gets inserted. I just have no way of knowing by how much it will get amplified, so for that reason I'd lean toward minimal spindle runout. They also claim to be the spindle manufacturer, so in theory they should know what they're talking about. Since the spindle itself is rated for only 75v, hopefully I could find a VFD somewhere that runs from 110v input voltage, which here is a lot more convenient, without having to wire for 220v or step 110v up to 220v just to meet the more typical Aliexpress VFD input requirement of 220v.
high speed 300W water cooled spindle motor 36000RPM 60000RPM 75V ER8 collet diameter 75mm milling spindle
300w Spindle kits For Intricate Carvings Water Cooled Spindle ER8 60000rpm spindle motor 1000Hz water cooling & 1.5kw inverter
I have MySensors node with 5 moisture sensors - work without problems for one year.
Arduino Pro Mini 5 V
RFM69HCW powered by 3,3V voltage regulator + resistors on communication lines
5x FDRobot moisture sensors
3x DS18B20 temperature sensors
powered by 5V, 1A power supply