My "Swallow"

Prologue

I decided to give my friend a sysadmin for his birthday a clock from a hard disk, which I read about in a habr. Attempts to create a normal, reliable device did not lead to anything. As I understand it, everyone has the same problem with balancing the rotating mechanism. I decided to destroy this problem in the bud.



Under the cat a few photos and videos created by the device, plus a description of the work. If the topic is interesting - I will definitely write about the development and show the source when I brush them.

At first I tried to repeat the famous Habra watch on the hard drive, but as a result I realized that the durable of that idea would not work because of the impossibility of perfect balancing. I decided to create my device.
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I bought several hard drives from different manufacturers, once again made sure that all the drives inside are exactly the same, except for Hitachi, and chose the internal design that I liked the most. It turned out to be a Maxtor hard drive.

It took 2 days to develop the board. Then he ordered a fee on the "Rezonite". To my surprise it turned out that they refused to make an urgent order with a black mask, I had to wait 2 weeks. After that, I saw my mistakes and the operation had to be repeated, but the time was already pressing and I found another company that agreed to fulfill my order in 3 days. To the pleasant surprise, the mask turned out to be more matte and less supported by slapping, which in the future was a huge plus in relation to the first device with a glossy mask.

I collected all the necessary. Small bugs still remained. To my disappointment, the reed switch had to be installed radially to the board due to double positives. Because of the small savings, making the mainboard one-sided, I did not provide for the inconvenient mounting of the compartment for a small battery. But only he who does nothing is not mistaken.

The sideplate consists of two 74HC595 shift registers and 16 LEDs with resistances. I thought it was the golden mean. Not very square font and not very zamorochennaya assembly.



Placed on the main board is a simple PIC16F1823, a real-time clock DS1307Z and the rest of the placer, a transistor and a button to raise the future tuning interface.



The program was written in MPLAB. There are no hidden pitfalls. Interrupt by timer counted the turnover period, then divided it and into the maine blew into registers by SPI. As soon as the frequency decreased, the controller fell asleep and removed power from the DS1307 and registers. And so on until the next impulses from the reed switch.

The interface is raised on a single button - long clamping "mode", quick "set".



The result of the work was a good manufacturability of the device and the reliability of the brick.
A friend was delighted with the gift and stuck for an hour spinning them.



UPD1:
Swallow Settings: