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Attiny84 based LED clock

There is never enough of digital clocks. They come in different shapes and ways of displaying time. Chris have put his own version of simple digital clock that is driven by attiny84 microcontroller. The indicator is made of 24 LEDs interfaced through couple of 74HC595s shift registers. LEDs are soldered in couple circles where one indicates hours and another minutes in 5 minute intervals. Seconds though are indicated by blinking LED. Clock is algorithm is run in software inside attiny. Code is written using Arduino, what made whole programming a lot easier. From looks of it it is hard to tell if there is an external crystal, so I wouldn’t expect great precision of time-count. Circuit was assembled on prototyping board which is well covered with semitransparent enclosure. Continue reading

There is never enough of digital clocks

AVR digital clock

If you would ask what is most popular microcontroller project ever, I would say digital clock. It seems that it should be that way – microcontroller itself is a ticking device so no surprise that “clock” comes first to the head. Here is another standard digital clock setup built by Kevin. As I mentioned standard I meant that it has all common parts needed to run it. First of all an AVR microcontroller, then DS3231 real time clock IC and four seven segment display. Clock is powered using regulated 5V DC power supply attached using two wires. But as all proper clocks it also has a backup coin cell battery. The PCB was manufactured using OSH Park services. They do great job by helping OSH community to get their designs… Continue reading

Digital clock with 32×8 LED matrix display

As it is said – digital clock with large screen is a great way to teach child read the clock. This clock is built on ATmega168 microcontroller that is this might seem and ordinary digital clock but there is one odd – it uses no RTC timer chip but internal timer that is being triggered via external crystal of 32.678kHz. So this allows generating exact 1sec intervals while AVR is running with internal system clock at 8MHz. Clock is equipped with two buttons that are led with audio tick and of course 32×8 LED display which gets data via SPI-like protocol (3 pins). And of course this clock was designed for kid – so it is enclosed in LEGO construction. Learning time can be fun. Continue reading