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
My 60k rpm is ER8, I guess the lighter collet/nut combo is less prone to vibrate, never seen a decent priced 60k rpm ER11.
ER 11 good is for heavy endmills, big collets, more than 3.175mm (1/8") shaft diameter, maybe 1/4" for table flattening.
The 60k rpm spindles are usually 300W, not a lot of power at lower rpm to do tough milling, so no use for larger endmills, ER8 is a good choice for fine milling with 1/8" shafted endmills.
My VFD is a Sunfar one, pretty decent I might say, I ran it for a few dozen hours now without issues.
PS. The best way to check for runout is the sound test, run the spindle empty, then with collet+nut, then with the endmill inserted. If I "tune" the position of a new endmill I can reach 60k rpm without any vibration at all, so I get almost no runout.
Yes, it is possible to contribute your own tutorial by creating a project on openhardware.io (it shares the same database as mysensors.org) and submit it for review. After publishing, I can "move" it to the mysensors.org site and you can continue editing it.
For long time contributors we can offer full editor rights which means you can update any article on the site. It's a bit scary to hand out this right to anyone so you'd have to prove yourself first
If something is wrong in the current articles, you can of cause pm us the error to be corrected.
There are a bunch of non-contact voltage detector videos on youtube:
Homemade Non-contact Voltage Detector – 04:19— Thomas Kim
Most are of a 3 transistor design, which from this video looks like it would be good enough for your purpose. If you wanted something even more sensitive (or greater range), you could use op-amps instead.