SDG #034 Circular LED Clock EC1515A DS1302

The EC1515A is one of the cheap solder it yourself kits that turns out to be far more satisfying than its price suggests. It arranges LEDs in a ring to form an analogue style face, driven by an 8051 family microcontroller with a DS1302 real time clock handling the timekeeping. A CR2032 cell on the board keeps the clock running when main power is removed, which is the difference between a kit plugged in for a demonstration and one that can be left on a shelf.

The build deserves some thought before starting. Kits like this involve a large number of through hole LEDs that all need to sit at a consistent height and orientation, so the soldering sequence matters more than the difficulty of any individual joint. Getting polarity wrong on a single LED in a ring of dozens is the classic failure mode, and it is much easier to check before the board is populated than after. The rest of the parts count is modest: the RTC, crystal, transistors, resistors and the battery holder.

For buyers, the useful points are that the visual result is genuinely attractive once powered, colour combinations are chosen at order time rather than mixed on the board, and the electronics are simple enough that faults are traceable. As a weekend beginner to intermediate soldering exercise it offers a great deal of practice per pound, with a finished object at the end rather than a blinking test board destined for a drawer.