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I have always been fascinated by the precision mechanics present in mechanical hard drives and every time I have a broken one I try to find a use for it.
This, together with the fact that I think it’s a shame to throw away such a precious piece of technology, made me think of this project.

The main idea of the project is to use the mechanics related to the movement of the magnetic head of an old hard disk to create a display showing the current time (it can be easily changed to display whatever you want).

By replacing the Hard disk magnetic head with a bar of leds and by turning on the leds at the right time it is possible, using the persistence of the human eye, to form an image. For the led bar I used one equipped with the well known LED WS2812B that gives the possibility to control the leds with only one pin (besides the power supply of course).

It should be noted that the flickering that you see in the video is not real. It is is probably due to interference between the scan frequency of my camera and the refresh rate of the display. Even the noise isn’t as noticeable as it sounds on the video.

I’d also like to point out that this is my first instructable, please forgive my inexperience.

A mechanical hard drive
An arduino board (e.g. Arduino pro mini or WAVGAT)
Two PMOS, e.g. AO3401 ( or any PMOS that can be driven at logic levels
Two NMOS, e.g. AO3406 ( or any NMOS that can be driven at logic levels
A real time clock module operating at 5 volt (e.g. RTC Mini module
Two 100 Ohm resistors
Two 4700 Ohm resistors
One capacitor (>220uf, > 10 volt)
Two M2.5 screws and nuts”

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