Reviving a classic secondary split-flap clock with Arduino
July twenty fifth, 2022—
On the planet of computing, many interfaces make the most of a main/secondary mannequin of uneven communication, wherein a main host gadget controls a number of secondary shopper gadgets. This mannequin is, for instance, widespread amongst PATA and SATA laborious drive preparations. It’s also widespread 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 possible got here from a set of many, which might have been utilized in a authorities constructing, practice station, or related software. 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 an alternative 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 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 velocity. A secondary motor prompts when crucial, equivalent to on the finish of February when the day must flip over to “01” early. The Nano drives the principle 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.