Earlier this week, we saw David Johnson-Davies’ minimalist ATtiny85 wrist watch that displays time using 12 LEDs arranged in a circle like a watch dial. I found another interesting LED-based wrist watch design shared by MACROFAB. It is a low cost watch based on Microchip PIC16F527 and it displays time in binary format. The PIC microcontroller runs in low-power crystal mode using a 32.768 KHz external crystal, that helps to achieve an accurate 1Hz signal required for timekeeping.
The Macro_Watch has 11 LEDs. Four LEDs for the Hour (H1 – H4), Six LEDs for the Minute (M1 – M6), and a single Seconds LED for timing purposes. This guide will not go into how to read binary but a good guide can be found here. Pressing the switch on the front will lit up the LEDs for 10 seconds to allow reading of the time. Holding the switch for 3 seconds will allow setting the current time. The time advances with acceleration so the longer the button is pressed the faster the time will increase. There is no AM/PM indicator on the watch. The SEC LED can be repurposed for AM/PM use or the user can look outside and see if the sun is out.