diagram ingram: digital

Showing posts with label digital. Show all posts

Monday, September 2, 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

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Tuesday, July 30, 2013

4 Bit Analogue to Digital Converter

The operation of the converter is based on the weighted adding and transferring of the analogue input levels and the digital output levels. It consists of comparators and resistors. In theory, the number of bits is unlimited, but each bit needs a comparator and several coupling resistors. The diagram shows a 4-bit version. The value of the resistors must meet the following criteria:

R1:R2 = 1:2;
R3:R4:R5 = 1:2:4;
R6:R7:R8:R9 = 1:2:4:8.

The linearity of the converter depends on the degree of precision of the value of the resistors with respect to the resolution of the converter, and on the accuracy of the threshold voltage of the comparators. This threshold level must be equal, or nearly so, to half the supply voltage. Moreover, the comparators must have as low an output resistance as possible and as high an input resistance with respect to the load resistors as feasible. Any deviation from these requirements affects the linearity of the converter adversely.

Circuit diagram:

4-Bit Analogue to Digital Converter Circuit Diagram

If the value of the resistors is not too low, the use of inverters with an FET (field-effect transistor) input leads to a near-ideal situation. In the present converter, complementary metal-oxide semiconductor (CMOS) inverters are used, which, in spite of their low gain, give a reasonably good performance. If standard comparators are used, take into account the output voltage range and make sure that the potential at their non-inverting inputs is set to half the supply voltage. If high accuracy is a must, comparators Type TLC3074 or similar should be used. This type has a totem-pole output. The non-inverting inputs should be interlinked and connected to the tap of a a divider consisting of two 10 kΩ resistors across the supply lines. It is essential that the converter is driven by a low-resistance source. If necessary, this can be arranged via a suitable op amp input buffer. The converter draws a current not exceeding 5 mA.

Source :www.extremecircuits.net

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Monday, July 8, 2013

Digital Step Km Counter

This circuit measures the distance covered during a walk. Hardware is located in a small box slipped in pants pocket and the display is conceived in the following manner: the leftmost display D2 (the most significant digit) shows 0 to 9 Km. and its dot is always on to separate Km. from hm. The rightmost display D1 (the least significant digit) shows hundreds meters and its dot illuminates after every 50 meters of walking. A beeper (excludable), signals each count unit, occurring every two steps. A normal step was calculated to span around 78 centimeters, thus the LED signaling 50 meters illuminates after 64 steps (or 32 operations of the mercury switch), the display indicates 100 meters after 128 steps and so on.

For low battery consumption the display illuminates only on request, pushing on P2. Accidental reset of the counters is avoided because to reset the circuit both pushbuttons must be operated together. Obviously, this is not a precision meter, but its approximation degree was found good for this kind of device. In any case, the most critical thing to do is the correct placement of the mercury switch inside of the box and the setting of its sloping degree.

Circuit diagram:
digital_step_km_counter_circuit_diagram

Digital Step-Km Counter Circuit Diagram

Parts:
R1 = 22K 1/4W Resistor
R2 = 2.2M 1/4W Resistor
R3 = 22K 1/4W Resistor
R4 = 1M 1/4W Resistor
R5 = 4.7K 1/4W Resistor
R6 = 47R 1/4W Resistor
R7 = 4.7K 1/4W Resistor
R8 = 4.7K 1/4W Resistor
R9 = 1K 1/4W Resistor
C1 = 47nF 63V Polyester Capacitor
C2 = 100nF 63V Polyester Capacitor
C3 = 10nF 63V Polyester Capacitor
C4 = 10µF 25V Electrolytic Capacitor
D1 = Common-cathode 7-segment LED mini-display (Hundreds meters)
D2 = Common-cathode 7-segment LED mini-display (Kilometers)
Q1 = BC327 45V 800mA PNP Transistors
Q2 = BC327 45V 800mA PNP Transistors
P1 = SPST Pushbutton (Reset)
P2 = SPST Pushbutton (Display)
IC1 = 4093 Quad 2 input Schmitt NAND Gate IC
IC2 = 4024 7 stage ripple counter IC
IC3 = 4026 Decade counter with decoded 7-segment display outputs IC
IC4 = 4026 Decade counter with decoded 7-segment display outputs IC
SW1 = SPST Mercury Switch, called also Tilt Switch
SW2 = SPST Slider Switch (Sound on-off)
SW3 = SPST Slider Switch (Power on-off)
BZ = Piezo sounder
B1 = 3V Battery (2 AA 1.5V Cells in series)

Circuit operation:

IC 1A & IC 1B form a monostable multi vibrator providing some degree of freedom from excessive bouncing of the mercury switch. Therefore a clean square pulse enters IC2 that divides by 64. Q2 drives the LED dot-segment of D1 every 32 pulses counted by IC2. Either IC3 & IC4 divide by 10 and drive the displays. P1 resets the counters and P2 enables the displays. IC1C generates an audio frequency square wave that is enabled for a short time at each monostable count. Q1 drives the piezo sounder and SW2 allows disabling the beep.

Notes:

Experiment with placement and sloping degree of mercury switch inside the box: this is very critical.
Try to obtain a pulse every two walking steps. Listening to the beeper is extremely useful during setup.
Trim R6 value to change beeper sound power.
Push P1 and P2 to reset.
This circuit is primarily intended for walking purposes. For jogging, further great care must be used with mercury switch placement to avoid undesired counts.
When the display is disabled current consumption is negligible, therefore SW3 can be omitted.

Streampowers

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Sunday, July 7, 2013

Digital Potentiometer Using DS1669

This DS1669 digital potentiometer circuit can be used for replacing your manual volume control in audio circuits.DS1669 are digital rheostats or potentiometers and provide 64 possible uniform tap points over the resistive range and are available in standard versions of 10K, 50K, and 100K ohms.The IC can be controlled by either a mechanical–type contact closure input or a digital source input such as a CPU
With this circuit we can control sound volume form an stereo audio amplifier.

Digital Potentiometer Circuit Using DS1669

When the S1 and S2 is push we can modify the level of sound (up or down). This integrated circuit is manufactured by Dallas Semiconductor and it can be use like a potentiometer in many applications like : contrast adjustment for an LCD or for level sound control. This digital volume controller IC is manufactured in dip or soic footprint (8 pins) and can be supply with an voltage between 4.5 and 8 volts DC.

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Thursday, July 4, 2013

Digital Bike Tachometer

This digital DIY tachometer for bikes uses two reed switches to get the speed information of the bicycle. The reed switches are installed near the rim of the wheel where permanent magnets pass by. The permanent magnets are attached to the wheelspokes and activate the reed switches everytime they pass by it. The speed is digitally displayed.

The tachometer circuit works according to this principle; the pulses created by the reed contacts are counted within a certain time interval. The resulting count is then displayed and represents the speed of the bike. Two 4026 ICs are used to count the pulses, decode the counter and control two 7-segment LED display. RS flip-flops U3 and U4 function as anti-bounce.

Electronic bicycle DIY tachometer Circuit diagram:

The pulses arrive at the counter’s input through gate U7. The measuring period is determined by monostable multivibrator U5/U6 and can be adjusted through potentiometer P1 so that the tacho can be calibrated. The circuit U1/U2 resets the counters.

Since batteries are used to power the circuit, it is not practical to support the continuous display of speed information. This circuit is not continuously active. The circuit is activated only after a button is pressed. At least three permanent magnets must be installed on the wheel. The circuit can be calibrated with the help of another pre-calibrated tachometer.

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Monday, April 8, 2013

PT2399 Digital Echo Circuit

Digital Echo Processor IC PT2399 is using CMOS technology in audio purposes. Digital Echo Processor PT2399 is implementing the system in the process of ADC and DAC audio repro echo.

Digital Echo Processor PT2399 has a high sampling frequency and 44K memory. Digital Echo Processor PT2399 to repro echo digital audio system of repro VCO delay time system that can be arranged. Digital Echo Processor PT2399 has a very low audio distortion of (THD <0.5%) and very low noise as well (No <-90dBV) so that the Digital Echo Processor PT2399 is capable of providing good audio quality.

Digital Echo Schematics

Description:
Setting the external resistor from 10 K Ohm to 50 K Ohm. If the value is greater then the Delay Time also increases.

Echo Digital Application Processor PT2399
Video Tape Recorder
Video Compact Disk
Television
CD Player
Car Stereo
KARAOKE Mixer
Electronic Musical
Echo Audio Processor

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