Antelope

Description

"Antelope" is a word clock I designed and built in December 2011.

It was inspired by QLOCKTWO, ClockTHREE, Doug's Word Clocks, and this Mikrocontroller.net Word Clock design.

The design, as well as the documentation here, is a work in progress.

Details

Hardware

100 LEDs, arranged in a 10x10 grid, light up letters spelling out the time in five-minute increments. An LED in each corner indicate additional in-between minutes.

The LEDs are driven by five Texas Instruments TLC5947 24-channel LED drivers. Each channel has 12-bits (4096 levels) of brightness control.

Time is kept by a Maxim DS3232 RTC. Backup power is supplied by a 0.2 F supercap. The time is set either automatically with a Radio clock module, or manually with four buttons on the back.

Power is supplied through a USB Micro-B port. A switching power supply provides 3.3V for the system and LEDs.

A light sensor provides ambient light feedback, so the brightness of the LEDs can be adjusted accordingly.

The clock is controlled by an NXP LPC1343 Cortex-M3 32-bit microcontroller. The LPC1343 can easily be reprogrammed via its onboard USB MSC bootloader.

Mechanical

The clock is 300mm x 300mm (almost 12" x 12") and is made from a stackup of the PCB and two pieces of acrylic.

The faceplate is 3mm clear acrylic, painted black, with laser-etched lettering. White paint over the lettering acts as a light diffuser. The faceplate is held in place by washers that mate with rare-earth magnets on the PCB.

The baffle is laser-cut 6mm black acrylic. It serves to optically isolate the individual LEDs. The PCB is mounted to the baffle with M3 screws.

Design

Hardware

Because of time constraints, I was unable to make a prototype. There are several errors in the first revision schematic & PCB layout. I will be publishing the second revision once the corrections are made. Please contact me if you'd like to see the first revision.