Reviving a classic secondary split-flap clock with Arduino

On the earth of computing, many interfaces make the most of a main/secondary mannequin of uneven communication, through which a main host gadget controls a number of secondary consumer units. This mannequin is, for instance, frequent amongst PATA and SATA exhausting drive preparations. It is usually frequent in clock networks, with a central time server updating a number of consumer clocks. iSax had a singular instance of such a consumer 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, practice station, or related utility. It will have obtained 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 a substitute of making an attempt 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 subtle, 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 supposed, the drive motor should spin at a really constant velocity. A secondary motor prompts when vital, comparable to on the finish of February when the day must flip over to “01” early. The Nano drives the primary 12V motor by way of an H-bridge and the second motor by way 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.