Reviving a classic secondary split-flap clock with Arduino

On this planet of computing, many interfaces make the most of a main/secondary mannequin of uneven communication, through which a main host machine controls a number of secondary shopper units. This mannequin is, for instance, frequent amongst PATA and SATA arduous drive preparations. It’s also frequent in clock networks, with a central time server updating a number of shopper clocks. iSax had a novel instance of such a shopper clock with a classic split-flap show, and made it helpful once more by retrofitting an Arduino board.

This clock probably got here from a set of many, which might have been utilized in a authorities constructing, prepare station, or related software. It will have acquired a sign from a main clock and set its time accordingly. Within the unique setup, that sign got here within the type of a 1Hz alternating sq. wave that drove a motor for the clockwork gears. As an alternative of trying to reverse-engineer and replicate that sign, iSax selected to drive the motor with an Arduino Nano board that retains its personal time with an RTC (real-time clock) module.

The mechanisms contained in the clock are very refined, controlling each a time show and a date show. These mechanisms even account for the variety of days in every month and leap years. For the mechanisms to work as meant, the drive motor should spin at a really constant pace. A secondary motor prompts when mandatory, equivalent to on the finish of February when the day must flip over to “01” early. The Nano drives the principle 12V motor by means of an H-bridge and the second motor by means of a 3.2V voltage regulator (as a result of that’s what iSax had readily available). 

Now iSax can get pleasure from the fantastic thing about this classic split-flap clock as a standalone unit that doesn’t require any exterior management.