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Have you ever wanted to know what your CPU usage was, but not wanted to use simple software like Windows Task Manager because it doesn't have enough lasers in it? Then you might like this thing I made, seen here inside my sister's PC:
It starts off with a Hall-effect sensor (the thing on the left of the photo below, wrapped in heatshrink and attached to some wires), which measures magnetic field strength. Since a wire carrying electric current generates a magnetic field, this can be used to indirectly measure current. Since the amount of current a CPU is using changes with how busy it is, this therefore measures CPU usage. The green ring is a magnetic core, which concentrates the magnetic field around the wire onto the sensor. There are some other parts to hold it all together on the CPU power cable.
The sensor is read by a microcontroller, and the microcontroller flashes some laser modules at a rate proportional to CPU usage. Both the board with the microcontroller and the laser modules are mounted on some lumps of ferrite magnet, so they can be stuck to a steel PC case.
And that's it. There's a more detailed description on my website, for anyone who still reads old-fashioned personal websites.
It starts off with a Hall-effect sensor (the thing on the left of the photo below, wrapped in heatshrink and attached to some wires), which measures magnetic field strength. Since a wire carrying electric current generates a magnetic field, this can be used to indirectly measure current. Since the amount of current a CPU is using changes with how busy it is, this therefore measures CPU usage. The green ring is a magnetic core, which concentrates the magnetic field around the wire onto the sensor. There are some other parts to hold it all together on the CPU power cable.
The sensor is read by a microcontroller, and the microcontroller flashes some laser modules at a rate proportional to CPU usage. Both the board with the microcontroller and the laser modules are mounted on some lumps of ferrite magnet, so they can be stuck to a steel PC case.
And that's it. There's a more detailed description on my website, for anyone who still reads old-fashioned personal websites.