fablab-wue / piClock

LED Clock based on Raspberri Pi Zero and pigpio-lib

piClock

A collection of LED Clocks based on Raspberri Pi Zero W. The library/deamon "pigpio" is used to handle up to 26 PWM channels for smooth blending the transitions.

BCD Clock

A classic BCD (binary coded decimal) clock with 18 or 20 LEDs (12h or 24h). Additional LEDs for am/pm and colon can be configured in software.

See detail description

Franconian Clock

A special word clock with 24 LEDs. It uses whole words per LED and a franconian style quater coding.

See detail description

Pro and Cons for using a Raspberry Pi instead of Arduino/ESP

Why RPi?

Pros:

• The RPi can use up to 26 GPIO pins directly without an additional port expander or shift register. Most smaller/cheaper controllers do not have enough pins to drive the 20 LEDs directly.
• The RPi has a built in current limiter on the GPIO pins. Resistors in line to LEDs are not necessary.
• The RPi Zero has onboard WiFi to get the correct time via NTP. No external RTC is needed.
• The RPi Zero has sufficient power and pins to run additional IoT features.
• Faster development (and code change).

Cons:

• Linux! Many steps to setup the controller. See chapter on GitHub Wiki...
• Linux! Potential security leaks to your local network.
• A little more expensive (about 20 Euro incl. MicroSD) than an ESP8266 (<7 Euro).

Why pigpio-lib?

Pros:

• This lib can handle software PWM for ALL 26 GPIOs without glitches.
• Faster than BCM-lib.
• Development and debugging can be done on your PC, remote-controlling the RPi GPIOs over the network.
• Implementation for several programming languages available.

Cons:

• pigpio-deamon eats 7...10 percent of CPU time continously, independent of how many GPIOs or PWMs are active.
• The lib's documentation leaves room for improvement.

Prepare the Raspberry Pi Zero

See detail description