Tuesday, March 31, 2009
Digital Clock with Alarm Using DS1307
DS1307 is a hardware realtime clock, which works on I2C protocol.
Better graphics using the same old fashioned alphanumeric LCD
(type HD44780). Icons which shows the status for Alarm ON/OFF
state, which gives a nice and cute look to the clock.
PIC Digital Clock Timer
This clock timer uses a PIC16F628 microcontroller to display 3
and 1/2 digit time and control an external load. The clock includes
a calendar with leap year and optional daylight savings adjustments.
The timer output can be set from 1 to 59 minutes and manually
switched on and off. The clock also has a correction feature that
allows an additional second to be added every so many hours to
compensate for a slightly slow running oscillator. The oscillator
uses a common 32.768 KHz watch crystal and the frequency can
be adjusted slightly with the 24pF capacitor on the right side of the
crystal.
PIC Digital Multiple Clock Timer
This circuit uses the PIC16F628 microcontroller to provide 4
timed outputs that can be programmed from 1 minute to 1 week.
An extra 8 bit shift register (74HC164) is used for the 4 timer
outputs and to display four additional indicator lights.
Digital Clock with Timer and Solar Panel Regulator
This is a combination digital clock timer and solar panel charge
controller used to maintain a deep cycle battery from a solar panel.
The timer output is used to control a 12 volt load for a 32 minute
time interval each day. Start time is set using 9 dip switches and
ends 32 minutes later. The 32 minute duration is set by selecting
the 5th bit (2^5 = 32) of a 4040 binary counter (pin 2). The timer
also has a manual toggle switch so the load can be manually
switched on or off and automatically shuts off after 32 minutes.
The time duration can be longer or shorter (8,16,32,64,128,256
minutes etc.) by selecting the appropriate bit of the counter.
The timer circuit is shown in the lower schematic just above the
regulator.
Digital Clock with Alarm Using DS1307
DS1307 is a hardware realtime clock, which works on I2C protocol.
Better graphics using the same old fashioned alphanumeric LCD
(type HD44780). Icons which shows the status for Alarm ON/OFF
state, which gives a nice and cute look to the clock.
PIC Digital Clock Timer
This clock timer uses a PIC16F628 microcontroller to display 3
and 1/2 digit time and control an external load. The clock includes
a calendar with leap year and optional daylight savings adjustments.
The timer output can be set from 1 to 59 minutes and manually
switched on and off. The clock also has a correction feature that
allows an additional second to be added every so many hours to
compensate for a slightly slow running oscillator. The oscillator
uses a common 32.768 KHz watch crystal and the frequency can
be adjusted slightly with the 24pF capacitor on the right side of the
crystal.
PIC Digital Multiple Clock Timer
This circuit uses the PIC16F628 microcontroller to provide 4
timed outputs that can be programmed from 1 minute to 1 week.
An extra 8 bit shift register (74HC164) is used for the 4 timer
outputs and to display four additional indicator lights.
Digital Clock with Timer and Solar Panel Regulator
This is a combination digital clock timer and solar panel charge
controller used to maintain a deep cycle battery from a solar panel.
The timer output is used to control a 12 volt load for a 32 minute
time interval each day. Start time is set using 9 dip switches and
ends 32 minutes later. The 32 minute duration is set by selecting
the 5th bit (2^5 = 32) of a 4040 binary counter (pin 2). The timer
also has a manual toggle switch so the load can be manually
switched on or off and automatically shuts off after 32 minutes.
The time duration can be longer or shorter (8,16,32,64,128,256
minutes etc.) by selecting the appropriate bit of the counter.
The timer circuit is shown in the lower schematic just above the
regulator.
Monday, March 30, 2009
Build a digital clock that turns AC load on/off with preset time
Figure 1 shows a circuit diagram of the Clock Controller V1.1.
P10-P1.7 drives 7-segment common anode LED with sink current.
P3.0-P3.3 also drives a base pin of 4-PNP transistor, 2n2907 with
sink current. As shown in the figure, the 2nd 2-digit LED that
connected to P3.2 and P3.3 is rotated 180 degrees to the 1st
2-digit allowing the pt. segment to be used for 1 second blinking.
P3.0-P3.3 also connects four momentary switches while the other
legs are tied to input port P3.4. During display and key switch
scanning, a logic '0' is shifted from P3.0 to P3.3, if there was a
key pressed, P3.4 then became low. P3.7 is a 1-bit sink current
driving, an example in the circuit uses a 2n2907 to drive a small
electromechanical relay 5V, say.
Blue Clock (Atmel Atmega8535 microcontroller)
The power comes in at the top left of the schematic. A bridge
rectifier is used so the polarity of the input signal doesn't matter.
A small SOT223 package, 5V regulator is used to provide
regulated voltage the Atmega8535, RTC, and the LED display
drivers. The Real Time Clock data is comes in from the PCF8563P.
This IC has a 32.768 crystal to keep time and a uses a 3V
CR2032 lithium battery when powered down. SW1 - SW4 are
the four pushbuttons for user input. The MBI5027 constant current
display drivers (24 pin DIP) from Macroblock can be a little hard
to find. They use power directly from the wall transform to turn
on the 7 segment LED's.
AVR 7-segment clock
The circuit can be viewed in every electronic book. Some
7-segments and LED's arranged as a matrix in rows and
colums and a multiplex routine written in assembler. The two
buttons are for setting the time.
Realtime clock with LED display and 89S8252
A real time clock using six 7-segment displays is used in this
project to display the time in HH-MM-SS format using a micro
controller ATMEL-89s8252 with minimum number of external
components. Five switches are used to set the HOURS
MINUTES (+/-) and one for zero reset of the clock display.
The micro controller runs of a 6Mhz crystal which also acts as
the time base for the clock.
Digital Clock with PIC16F84A
This is a small ajustable clock, I made based on PIC16F84A
microchip.The hardware part is very simple because it only
uses 74hct238 demultiplexer, 4x7 segments, and some rezistors.
The software part is programmed through a device connected to
serial port with icprog and made/debuged with MPlab.
Build a digital clock that turns AC load on/off with preset time
Figure 1 shows a circuit diagram of the Clock Controller V1.1.
P10-P1.7 drives 7-segment common anode LED with sink current.
P3.0-P3.3 also drives a base pin of 4-PNP transistor, 2n2907 with
sink current. As shown in the figure, the 2nd 2-digit LED that
connected to P3.2 and P3.3 is rotated 180 degrees to the 1st
2-digit allowing the pt. segment to be used for 1 second blinking.
P3.0-P3.3 also connects four momentary switches while the other
legs are tied to input port P3.4. During display and key switch
scanning, a logic '0' is shifted from P3.0 to P3.3, if there was a
key pressed, P3.4 then became low. P3.7 is a 1-bit sink current
driving, an example in the circuit uses a 2n2907 to drive a small
electromechanical relay 5V, say.
Blue Clock (Atmel Atmega8535 microcontroller)
The power comes in at the top left of the schematic. A bridge
rectifier is used so the polarity of the input signal doesn't matter.
A small SOT223 package, 5V regulator is used to provide
regulated voltage the Atmega8535, RTC, and the LED display
drivers. The Real Time Clock data is comes in from the PCF8563P.
This IC has a 32.768 crystal to keep time and a uses a 3V
CR2032 lithium battery when powered down. SW1 - SW4 are
the four pushbuttons for user input. The MBI5027 constant current
display drivers (24 pin DIP) from Macroblock can be a little hard
to find. They use power directly from the wall transform to turn
on the 7 segment LED's.
AVR 7-segment clock
The circuit can be viewed in every electronic book. Some
7-segments and LED's arranged as a matrix in rows and
colums and a multiplex routine written in assembler. The two
buttons are for setting the time.
Realtime clock with LED display and 89S8252
A real time clock using six 7-segment displays is used in this
project to display the time in HH-MM-SS format using a micro
controller ATMEL-89s8252 with minimum number of external
components. Five switches are used to set the HOURS
MINUTES (+/-) and one for zero reset of the clock display.
The micro controller runs of a 6Mhz crystal which also acts as
the time base for the clock.
Digital Clock with PIC16F84A
This is a small ajustable clock, I made based on PIC16F84A
microchip.The hardware part is very simple because it only
uses 74hct238 demultiplexer, 4x7 segments, and some rezistors.
The software part is programmed through a device connected to
serial port with icprog and made/debuged with MPlab.
