4-Channel Timer Known as xTimer

Figure 1 

The project was design to be suitable with energy saving applications since it has simple hardware and nice firmware with C coding, making this 4-channel timer easy to build.

The timer device utilizes Atmel AT89C4051 and MAX7219 and it contains automatic power down mode, simple settings, 8-digit LED display, and an optional buzzer for sounding the alarm. The LED module with MAX7219 is a ready-made with 10-pin header for easy plug-in to the 4051 board. The 8-digit LED allows the use of four timers with two digits each where the right hand side containing timer 1 & 2 are for Minute counting while the left hand side using timer 3 & 4 are for Hour counting. To enable the use of 20-pin 89C405a MCU, the MAX7219 needs serial interface like the SPI while being software controlled. The display will show 0 and the output bit is activated during time-out.

There are only three signals needed by the MAX7219 including CLK, DIN, and LOAD, which are software generated assembly code. The DC current being drawn when LEDs are light is 90mA at 5V and it will be around 10mA when in power down mode.

Rest of the project