New Google Classroom update makes it harder to cheat on quizzes | 19mm Momentary Push Button

If you insure that your HV and LV systems are completely separate, and joined only by UL registered galvanically isolating components, only then can you be prepared to say that the logic portion of your system is safe. And doing that maybe won’t make fewer things capable of going wrong, but at least fewer things capable of spectacularly dangerous failure.

A clean filter is vital to a well-functioning air conditioner. During the summer it is good to check your filters once a month. If you have pets, leave windows and doors open, or have allergies, you may need to change your filter more often.

I probably ought to be dead, or have some scars at least, but apparently I’m a very resistant person.

I don’t know about anywhere else, but in North America, power enters the home via two 120V hot and one neutral. The two 120V hot legs are out of phase with each other, and when combined, you get 240V. So, from the breaker panel, you can pull 120V or 240V, depending on the type of breaker you insert at a given position. Some large appliances (water heaters, central AC units, electric stoves, large power tools) are 240V in North America, but most everything else is designed for a single leg 120V feed. Then just to make things even more complicated, large industrial businesses often have three phase 480V for the really big equipment.

If you wrap your own coil, consider wrapping a thermistor or thermocouple into the windings. Insides may heat up before outsides. Expoxies have limits. You don’t want failure halfway up 50 stories, whether mangni-shoes or a load of pig iron.

Dust particles are often flammable, in high densities this means they’re explosive. https://en.wikipedia.org/wiki/Dust_explosion

If you have an older system, you might like to see more of a pool system rebuild. If you are interested in controlling the pool chemistry, we’ve seen that before, too.

Gardner Minshew II threw two touchdown passes and ran for another score and No. 12 Washington State stopped No. 25…

Zaprodk bitches about the absence of a fuse — which is clearly explained to be located on a separate power entry board.

A fun read is the Boeing’s space station power system document that describes the DC power system on the ISS: http://www.boeing.com/assets/pdf/defense-space/space/spacestation/systems/docs/ISS%20Electric%20Power%20System.pdf

First off, I would set the system up more like a safety-critical system. I would have an independent, segregated processor running the heated bed. I would have checks in the system processor and re-checks built into an independent circuit built from discrete analog/digital circuits on the system. I would use two, independent temperature sensors on the board, plus at least one thermal fuse, as well as one overload protection mechanism (most likely a fuse).

I neither would recommend the mains power approach (230V in Europe), the power of 120W is very well to be handled with 24V, even 36V is necessary. This 3D printers are in many cases still some kind of “hacker toy”, often are modifications or experiments done.