Showing posts with label clock. Show all posts
Showing posts with label clock. Show all posts
Friday, October 24, 2014
Simple Clock pulse Generator with CD4049
If you want to generate clock with CD4049 CMOS you can do as the follow picture.The typical resister values is 100K and Capacitor is 0.01-0.1uF.The output frequency is about 1/1.1RC ___Hz
Friday, January 24, 2014
Digital Clock Based on Sam Gordon Theory
The circuit was designed to implement the concept of Sam Gordon in making a digital clock with visible components from the viewer of the clock.
The supplied voltage of the circuit is shared into two lines where the 5 VA supplied with voltage in case of breakdown in network voltage, supplies all the ICs except the IC9 to IC13 which is being supplied by 5 VB. A battery is alternatively used in the case of interruption of circuit voltage. The second figure shows the indication of the display as it is driven by IC9 to IC13 where CMOS 4511 is used. The diodes DIS1 to DIS5 are conducting as common cathode while DIS6 will always be common anode. The use of 74LS47 will cause the DIS1 to DIS5 to conduct at common anode with their pins 1 and 6 going to the line of 5 VB with R39 and R40 to 0 V line. The dot in DIS3 and DIS5 is turned ON by these resistors to produce a division of LED displays.
There are two ways, found in the initial startup of operation, by which the 1 Hz pulse can be produced which constitute to the basis of time for the clock. The two methods consist of using a crystal oscillator with high oscillation frequency and the division of this frequency to create 1 Hz in the end. This would ensure a very précised and stable operation in producing the pulses. The crystal oscillator in figure 3 produces the 1 MHz frequency that is divided in stages from the IC15 up to IC17.
The gates A and B of IC18 and IC19 are not initially included in the operation unless the switches S1 or S2 are pressed to modify the time. Pressing the Super Fast (S1), would release a frequency pulse of 10 KHz while pressing Fast (S2) would release a pulse frequency of 100 Hz, to show indication to the display concerning the modification of time in a short interval. The figure 3 circuit is being supplied by 5 VA where the operation of oscillator is ensured, even in the event of voltage interruption, which would trigger the use of the battery.
Figure 4 also introduced the usage of crystal oscillator to produce 1 Hz in the output of SL19. This frequency is made possible by successive division 3.2768 MHz frequency coming from the oscillator, in the start of the operation. The presence of variable capacitor C3 is for altering the oscillator in order to test the frequency pulse at 204800 Hz. The indication of display is regulated by the switches S1 (fast) and S2 (super fast) for having a frequency of 10 Hz and 100 Hz respectively. The adjustment of time will be in a short interval, since the indication of display runs very fast. The use of mechanic switches is preferred due to simplicity. The circuit is similarly powered as in figure 3.
The fifth figure shows the power supply as it provides the necessary voltage for the operation of the circuit, together with the charging mechanism for the battery and the transfer in battery during voltage interruptions. The output from this supply circuit is regulated by the trimmer TR1 to produce 5 V at P1 to enable the functionality of the circuit. The next trimmer TR2 regulates IC25 as it gives 6.9 V at P2, which charges the lead acid battery which is rated 6V per 1 Ah, connected to SL17. During voltage interruption, the relay RL1 is triggered where its contacts connect the 5 VA line to the 6 V battery via the D5 and D6while 5 VB is connected to 0 V where the display stops.
The duration by which the contacts transfer from one state to the other is determined by C17. The IC24 and IC25 should be placed in a heatsink and be regulated with TR1 and TR2 without being connected to the supply circuit except during the use of batteries.The concept of the circuit is also embraced in other digital clocks. And because they are small inexpensive devices with LED displays, they are typically found in automobile clocks, desk clocks, microwave ovens, industrial clocks, computers, interval timers, radios, and televisions.
- Sam Clock – a digital clock equipment that is fully parametric or constantly varying with its parameters of function and construction, which has been operational for many years without problems on a 24 hour basis.
- 74HC – a quad 2-input NAND gate with standard output capability, and is high speed Si-gate CMOS device that is pin compatible with low power Schottky TTL and specified in compliance with JEDEC standard no. 7A.
- 74LS – a monolithic decade and binary counter that contains four master-slave flip flops and additional gating to provide a divide-by-two counter and a 3-stage binary counter with typical power dissipation of 45 mW and count frequency of 42 MHz.
- 4060 – a 14-bit ripple counter with internal oscillator that has glitches which may occur in any logic gate systems connected to its outputs due to the slight delay before the later counter outputs respond to a clock pulse.
- LM317 – an adjustable 3-terminal positive voltage regulator capable of supplying in excess of 1.5A over an output voltage range of 1.2V to 37V and requires only two external resistors to set the output voltage due to its internal current limiting, thermal shutdown and safe area compensation, making it essentially blow-out proof.
- 4017 – a decade counter where the count advances as the clock input becomes high that may be combined with diodes for some functions such as flash sequences.
The supplied voltage of the circuit is shared into two lines where the 5 VA supplied with voltage in case of breakdown in network voltage, supplies all the ICs except the IC9 to IC13 which is being supplied by 5 VB. A battery is alternatively used in the case of interruption of circuit voltage. The second figure shows the indication of the display as it is driven by IC9 to IC13 where CMOS 4511 is used. The diodes DIS1 to DIS5 are conducting as common cathode while DIS6 will always be common anode. The use of 74LS47 will cause the DIS1 to DIS5 to conduct at common anode with their pins 1 and 6 going to the line of 5 VB with R39 and R40 to 0 V line. The dot in DIS3 and DIS5 is turned ON by these resistors to produce a division of LED displays.
There are two ways, found in the initial startup of operation, by which the 1 Hz pulse can be produced which constitute to the basis of time for the clock. The two methods consist of using a crystal oscillator with high oscillation frequency and the division of this frequency to create 1 Hz in the end. This would ensure a very précised and stable operation in producing the pulses. The crystal oscillator in figure 3 produces the 1 MHz frequency that is divided in stages from the IC15 up to IC17.
The gates A and B of IC18 and IC19 are not initially included in the operation unless the switches S1 or S2 are pressed to modify the time. Pressing the Super Fast (S1), would release a frequency pulse of 10 KHz while pressing Fast (S2) would release a pulse frequency of 100 Hz, to show indication to the display concerning the modification of time in a short interval. The figure 3 circuit is being supplied by 5 VA where the operation of oscillator is ensured, even in the event of voltage interruption, which would trigger the use of the battery.
Figure 4 also introduced the usage of crystal oscillator to produce 1 Hz in the output of SL19. This frequency is made possible by successive division 3.2768 MHz frequency coming from the oscillator, in the start of the operation. The presence of variable capacitor C3 is for altering the oscillator in order to test the frequency pulse at 204800 Hz. The indication of display is regulated by the switches S1 (fast) and S2 (super fast) for having a frequency of 10 Hz and 100 Hz respectively. The adjustment of time will be in a short interval, since the indication of display runs very fast. The use of mechanic switches is preferred due to simplicity. The circuit is similarly powered as in figure 3.
The fifth figure shows the power supply as it provides the necessary voltage for the operation of the circuit, together with the charging mechanism for the battery and the transfer in battery during voltage interruptions. The output from this supply circuit is regulated by the trimmer TR1 to produce 5 V at P1 to enable the functionality of the circuit. The next trimmer TR2 regulates IC25 as it gives 6.9 V at P2, which charges the lead acid battery which is rated 6V per 1 Ah, connected to SL17. During voltage interruption, the relay RL1 is triggered where its contacts connect the 5 VA line to the 6 V battery via the D5 and D6while 5 VB is connected to 0 V where the display stops.
The duration by which the contacts transfer from one state to the other is determined by C17. The IC24 and IC25 should be placed in a heatsink and be regulated with TR1 and TR2 without being connected to the supply circuit except during the use of batteries.The concept of the circuit is also embraced in other digital clocks. And because they are small inexpensive devices with LED displays, they are typically found in automobile clocks, desk clocks, microwave ovens, industrial clocks, computers, interval timers, radios, and televisions.
Friday, December 27, 2013
Binary Coded Decimal BCD Clock
The clock circuit above uses seven ICs and 19 LEDs to indicate binary coded decimal time. The LEDs can be arranged (as shown in example above) so that each horizontal group of 3 or 4 LEDs represents a decimal digit between 0 and 9 and each individual LED represents a single bit or (binary digit) of the value. Binary digits have only two values (0 and 1) so a number written in binary would be something like 1001 or 0011, which represents decimal numbers 9 and 3 respectively. From right to left, each binary (1) represents increasing powers of 2, so that a 1 in the right hand place represents 2^0=1 and the next place to the left is 2^1=2 and then 2^2=4, and so forth.
This makes binary counting fairly easy since each digit has a value of twice the one before or 1,2,4,8,16,32,64,etc. Thus the decimal value can be found by simply adding the values of each illuminated LED in the same row, (the total is shown in the box to the right). For example, the binary number 1001 would have a decimal value of 8+0+0+1 = 9. But this is actually a binary coded decimal 9 since only values from 0 to 9 are used 0000 to 1001. A true binary clock indicating minutes of the hour would display values from 0 to 59, or 000000 to 111011. But this would be more difficult to read since adding values 32 + 16 + 8 + 2 + 1 = 59 is not as easy as 8 + 0 + 0 + 1 = 9.
Binary Coded Decimal (BCD) Clock Circuit diagram
The circuit is powered by a small 12.6 VAC transformer which also provides a low voltage 60 Hz signal for a very accurate time base. The transformer is connected with the secondary center tap at ground which produces about 8 volts DC across the 3300uF filter capacitor. DC power for the circuit is regulated at about 5.5 using a NPN transistor (2N3053) and 6.2 volt zener diode. The 2N3053 gets a little warm when several LEDs are on, and may require a little (top hat type) heat sink.
A one second clock pulse is obtained by counting 60 cycles of the AC line signal. This is accomplished using a CMOS CD4040 12 stage binary counter (shown in light blue). The 60th count is detected by the two NAND gates connected to pins 2,3,5,and 6 of the counter. When all four of these lines are high, the count will be 60 resulting in a high level at pin 4 of the 74HC14 which resets the counter to zero and advances the seconds counter (74HC390 shown in purple) when pin 4 returns to a low state.
The same process is used to detect 60 seconds and 60 minutes to reset the counters and advance the minutes and hours counters respectively. In both of these cases the 2 and 4 bit lines of the tens counter section will be high (20+40=60). In all three cases (seconds, minutes and hours) a combination 10K resistor and 0.1uF capacitor is used at the input to the 74HC14 inverter to extend the pulse width to about 300uS so the counters will reliably reset. Without the RC parts, the reset pulse may not be long enough to reset all stages of the counter since as soon as the first bit resets, the inputs to the NAND gate will no longer all be high and the reset pulse will end. Adding the RC parts eliminates that possibility.
The reset process for the hours is a little different since for a 12 hour clock we need to reset the hours counter on the 13th count and then advance the counter one count so the display will indicate one ("1"). The 74HC00 quad NAND gate only has 4 sections with two inputs each so I used 3 diodes to detect the 13th hour (10 +1 +2 =13) which drives an inverter and also a transistor inverter (2N3904 or similar). The last 74HC14 inverter stage (pin 12 and 13) supplies a falling edge to the hours counter which advances the hours to "1" a short time after the reset pulse from the transistor inverter ends.
The pulse width from pin 12 of the inverter is a little shorter than from pin 10 which ensures that the hours clock line (pin 1 of yellow box) will move high before the end of the reset pulse form pin 10. If it were the other way around, the reset pulse may end before pin 12 of the inverter had a chance to reach a high level which would prevent the counter from advancing to "1". So it is important to use a shorter RC time at pin 13 than for the other Schmitt Trigger inputs. I used a 10K resistor and a 0.01uF cap to obtain the shorter time, but other values will work just as well. Only 2 sections of the 4071 OR gate are used, so the remaining 4 inputs (pins 8,9,12,13) should be terminated to ground if not used.
Copied Files Notice: This circuit diagram and text description has been copied and reposted without permission at: http://www.csgnetwork.com/binclockschnpl.html. The copied file has also been altered to remove the authors name and date of creation which is a clear violation of copyright law. They have also copied and modified three Java Script Calculators from this website. I have e-mailed a request to have the calculators removed and received no answer. I have also contacted the web host at Verio.net and received an autoresponse that the matter will be investigated but I doubt any action will occur. Please feel free to e-mail your opinions of plagiarism to webmaster@csgnetworks.com
Parts List:
3 - 74HC390 - Dual BCD counters
1 - CD4040 - 12 Stage Binary Counter
1 - 74HC14 - Hex Schmitt Trigger Inverter
1 - 74HC00 - Quad NAND gate
1 - CD4071 - Quad OR gate
1 - 2N3053 - NPN transistor (may need heat sink)
1 - 2N3904 - NPN transistor
3 - 1N914 - Signal diode (1N400X will also work)
2 - 1N400X - Rectifier diodes
1 - 6.2 volt - Zener diode
1 - 3300uF - Filter Capacitor - 16 volt
1 - Power Transformer - Radio Shack 273-1365A or similar
1 - 220K 1/4 or 1/8 watt resistor
1 - 150 ohm 1/4 watt resistor
19 - 220 ohm 1/4 or 1/8 watt resistors
11 - 10K 1/4 or 1/8 watt resistors
2 - 0.01uF capacitors
4 - 0.1uF capacitors
19 - Red LEDs (15 mA)
2 - Momentary push button switches (to set the time)
1 - Toggle switch (to start the clock at a precise time)
This makes binary counting fairly easy since each digit has a value of twice the one before or 1,2,4,8,16,32,64,etc. Thus the decimal value can be found by simply adding the values of each illuminated LED in the same row, (the total is shown in the box to the right). For example, the binary number 1001 would have a decimal value of 8+0+0+1 = 9. But this is actually a binary coded decimal 9 since only values from 0 to 9 are used 0000 to 1001. A true binary clock indicating minutes of the hour would display values from 0 to 59, or 000000 to 111011. But this would be more difficult to read since adding values 32 + 16 + 8 + 2 + 1 = 59 is not as easy as 8 + 0 + 0 + 1 = 9.
Binary Coded Decimal (BCD) Clock Circuit diagram
A one second clock pulse is obtained by counting 60 cycles of the AC line signal. This is accomplished using a CMOS CD4040 12 stage binary counter (shown in light blue). The 60th count is detected by the two NAND gates connected to pins 2,3,5,and 6 of the counter. When all four of these lines are high, the count will be 60 resulting in a high level at pin 4 of the 74HC14 which resets the counter to zero and advances the seconds counter (74HC390 shown in purple) when pin 4 returns to a low state.
The same process is used to detect 60 seconds and 60 minutes to reset the counters and advance the minutes and hours counters respectively. In both of these cases the 2 and 4 bit lines of the tens counter section will be high (20+40=60). In all three cases (seconds, minutes and hours) a combination 10K resistor and 0.1uF capacitor is used at the input to the 74HC14 inverter to extend the pulse width to about 300uS so the counters will reliably reset. Without the RC parts, the reset pulse may not be long enough to reset all stages of the counter since as soon as the first bit resets, the inputs to the NAND gate will no longer all be high and the reset pulse will end. Adding the RC parts eliminates that possibility.
The reset process for the hours is a little different since for a 12 hour clock we need to reset the hours counter on the 13th count and then advance the counter one count so the display will indicate one ("1"). The 74HC00 quad NAND gate only has 4 sections with two inputs each so I used 3 diodes to detect the 13th hour (10 +1 +2 =13) which drives an inverter and also a transistor inverter (2N3904 or similar). The last 74HC14 inverter stage (pin 12 and 13) supplies a falling edge to the hours counter which advances the hours to "1" a short time after the reset pulse from the transistor inverter ends.
The pulse width from pin 12 of the inverter is a little shorter than from pin 10 which ensures that the hours clock line (pin 1 of yellow box) will move high before the end of the reset pulse form pin 10. If it were the other way around, the reset pulse may end before pin 12 of the inverter had a chance to reach a high level which would prevent the counter from advancing to "1". So it is important to use a shorter RC time at pin 13 than for the other Schmitt Trigger inputs. I used a 10K resistor and a 0.01uF cap to obtain the shorter time, but other values will work just as well. Only 2 sections of the 4071 OR gate are used, so the remaining 4 inputs (pins 8,9,12,13) should be terminated to ground if not used.
Copied Files Notice: This circuit diagram and text description has been copied and reposted without permission at: http://www.csgnetwork.com/binclockschnpl.html. The copied file has also been altered to remove the authors name and date of creation which is a clear violation of copyright law. They have also copied and modified three Java Script Calculators from this website. I have e-mailed a request to have the calculators removed and received no answer. I have also contacted the web host at Verio.net and received an autoresponse that the matter will be investigated but I doubt any action will occur. Please feel free to e-mail your opinions of plagiarism to webmaster@csgnetworks.com
Parts List:
3 - 74HC390 - Dual BCD counters
1 - CD4040 - 12 Stage Binary Counter
1 - 74HC14 - Hex Schmitt Trigger Inverter
1 - 74HC00 - Quad NAND gate
1 - CD4071 - Quad OR gate
1 - 2N3053 - NPN transistor (may need heat sink)
1 - 2N3904 - NPN transistor
3 - 1N914 - Signal diode (1N400X will also work)
2 - 1N400X - Rectifier diodes
1 - 6.2 volt - Zener diode
1 - 3300uF - Filter Capacitor - 16 volt
1 - Power Transformer - Radio Shack 273-1365A or similar
1 - 220K 1/4 or 1/8 watt resistor
1 - 150 ohm 1/4 watt resistor
19 - 220 ohm 1/4 or 1/8 watt resistors
11 - 10K 1/4 or 1/8 watt resistors
2 - 0.01uF capacitors
4 - 0.1uF capacitors
19 - Red LEDs (15 mA)
2 - Momentary push button switches (to set the time)
1 - Toggle switch (to start the clock at a precise time)
Thursday, December 12, 2013
Digital Clock Using with PIC16C54
Digital clock project based on the PIC16C54 microcontroller can be designed using the following circuit diagram . This digital clock electronic project based on the PIC16C54 is a simple time-of-day clock incorporating four seven-segment LED displays and three input switches. There is also an additional reset switch that would not normally be incorporated into the final design.
Digital clock Circuit diagram
The common cathode for each display is turned on with transistors connected to the four I/O lines of PORTA . A low output turns on the PNP transistor for the selected display. The PORTB pins activate the LED segments.
The PORTB pins activate the LED segments. The switches are also connected to PORTB I/O pins.
When no buttons are pressed, the circuit will display the current time, starting at 12:00 on reset.
Pressing SW1 will cause seconds to be displayed. The time is set by pressing SW2 to advance minutes, and SW3 to advance hours . The displays used were common cathode and turned on with transistors to avoid trying to sink too much current into the PIC16C5X. 100 W resistors were used in series with the segments to obtain the desired brightness. Different values may be required if different displays are used.
All of the same display segments are linked together (A-A-A-A, B-B-B-B, etc.) and are individually selected by turning on only the desired display.
This simple digital clock project based on the PIC16C54 microcontroller must be powered from a simple 5 volt DC power supply circuit .
This digital clock project based on the PIC16C54 microcontroller ( circuit and software ) was designed by Dan Matthews Microchip Technology Inc . Download Source Code
Digital clock Circuit diagram
The common cathode for each display is turned on with transistors connected to the four I/O lines of PORTA . A low output turns on the PNP transistor for the selected display. The PORTB pins activate the LED segments.
The PORTB pins activate the LED segments. The switches are also connected to PORTB I/O pins.
When no buttons are pressed, the circuit will display the current time, starting at 12:00 on reset.
Pressing SW1 will cause seconds to be displayed. The time is set by pressing SW2 to advance minutes, and SW3 to advance hours . The displays used were common cathode and turned on with transistors to avoid trying to sink too much current into the PIC16C5X. 100 W resistors were used in series with the segments to obtain the desired brightness. Different values may be required if different displays are used.
All of the same display segments are linked together (A-A-A-A, B-B-B-B, etc.) and are individually selected by turning on only the desired display.
This simple digital clock project based on the PIC16C54 microcontroller must be powered from a simple 5 volt DC power supply circuit .
This digital clock project based on the PIC16C54 microcontroller ( circuit and software ) was designed by Dan Matthews Microchip Technology Inc . Download Source Code
Subscribe to:
Posts (Atom)