magnets are expensive

Indeed, world wide demand for rare metals is zooming in now years. This was not the situation in prior. Sadly, the problem is that rare earths are well very rare. Due to need for magnets for electric cars. Also, for hybrids like the prius. What we see is soaring prices.

Barium oxide bar magnet is what we use. Those magnets are not affected by the shortage, but they do not have as much power. Hope that in the future we find a way. Yeah, to make magnets less expensive.