Readout Circuit

With this counter you can count laps for example (in conjunction with the Simple light trap ). The circuit uses two TTL ICs 74LSxx the series. The left IC is a decimaalteller. The input pulses 14 are counted and converted to the corresponding BCD code. This code is passed to the second IC, which is a code converter and display driver. Here the BCD code correct the display driver for LD1. ..

99 mV to 999 mV meter schematic

99 mV to 999 mV meter schematic

This circuit can for example be incorporated into a diet to pressure warning. The meter can measure voltages from -99 mV to 999 mV. The circuit uses two ICs, the CA 3161 and CA 3162. IC1 converts the analog signal into a digital signal. IC1 is also the multiplexed signal to T1-T3 can be controlled. The BCD code is then fed to IC1 IC2, a BCD/7-segments converter. Then the signal is fed to the displays. Pin 6 of IC1 (hold) can be used for a number of things. When pin 6 is grounded or open, the 4 Hz sampling frequency. When pin 6 is at 1.2 V, then enter the HOLD function is activated. ..

Digital Clock Timer schematic

Digital Clock Timer schematic

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...

Digital Countdown schematic with 555

Digital Countdown schematic with 555

This circuit provides a visual 9 second delay using a 7 segment digital readout LED. When the switch is closed, the CD4010 up/down counter is preset to 9 and the 555 timer is disabled with the output held high. When the switch is opened, the timer produces an approximate 1 second clock signal, decrementing the counter until the 0 count is reached. When the zero count is reached, the 'carry out' signal at pin 7 of the counter moves low, energizing the 12 volt relay and stopping the clock with a low signal on the reset line (pin 4). The relay will remain energized until the switch is again closed, resetting the counter to 9. The 1 second clock signal from the 555 timer can be adjusted slightly longer or shorter by increasing or decreasing the resistor value at pin 3 of the timer. ..

Digital Voltmeter with ICL7129ACPL A/D converter

Digital Voltmeter with ICL7129ACPL A/D converter

This 4 1/2-digit DVM circuit is built around a Maxim ICL7129ACPL A/D converter and LCD driver. An ICL8069 CCZR 1.2-V band-gap reference diode is used for a voltage reference. S2a-b-c select one of four ranges up to 200 V (maximum). The meter also has a piezoelectric buzzer for continuity testing. S3 selects either DVM or continuity. Crystal 1 can be changed to 100 kHz if maximum rejection of 50 Hz is desired. The crystal normally provides 120 kHz for best 60-Hz rejection. This is caused by the dual-slope conversion technique used in IC1...

Digital Up / Down Counter

Digital Up / Down Counter

This Circuit uses a CD40110BE, Up/Down Counter IC's. This IC is able to Source Each Segment with 25 mA, Giving a Very Nice Bright Display. The 7 Segment Displays MUST be a Common Cathode Type, as I have used here. All the UnMarked Resistors should be at least 680 Ohms for Up To 12 Volts Supply Voltage. For Higher Supply Voltages up to 18 volts or Reduced Currents, I would suggest Increasing these Values to 1500 Ohms. Or if you want "Reduced Power" and "Brightness", Adjust the resistor values as appropriate. Basically the Approximate Current is Supply voltage Minus 2, Divided by the Resistor Value. The Schematic posted here Only shows the First, Second, Third and Last Stages. And This board is for a counter of up to 9999. ..

1 GHz Frequency Counter

1 GHz Frequency Counter

This very simple counter can be used to measure the frequency of various wireless devices. Applies in reviving the transmitter and its operation as a control monitor frequency. It can be used as a scale to the receiver. Due to the simplicity of the counter should not miss any of the equipment bastlí?e that similar facilities are still owned. Buying the parts is not a significant financial burden and required the program to the PIC is available for download. To measure the frequency of the oscillator (either the transmitter or receiver), use coaxial cable (RG58 is suitable) connected to the input port counters. At the end of the cable loop from the solder wire and place it on the oscillator coil. In some cases, the cable can be connected through a resistance of about 1 to the output amplifier stage for the oscillator...

Digital Clock

Digital Clock

The digital clock of circuit, has as base one IC, the MM5314N, in which are contained all the circuits that need. The IC1 collaborates with six Display of common anode, that are not critically as materials. You can select what dimension, you want it is enough you adapt pins their in the circuit. The display are drive by a system of polyplexis and are drive by thirteen transistors. For timing the circuit, is used the frequency of network (50HZ). This solution is the simplest, that it is not best. For more constant frequency you can use a circuit that would be based on crystal, (it will be given shortly). For the clue of hour are used six display of 7 element common anode. The DS1-DS2, show the hours (decades-unit respectively), the DS3-DS4, show the minutes and DS5-DS6, the seconds. ..

Frequency counter up to 1MHZ

Frequency counter up to 1MHZ

The MK50398 is one modern decimal counter up/down of six tens, with control of screen LED of seven segments and flip-flop of storage. Counter it can measure additive and abstractively. The IC MK50398 is ideal for manufacture frequency counter as the particular circuit. The frequency of measurement is from 0 HZ until roughly 1MHZ. ..

Roulette with LED Display

Roulette with LED Display

This circuit is a small digital ?roulette''. It is constituted by oscillator IC1, the counter IC2, the transistors Q1-7 that drive the display common cathode DSP1. The supply basically becomes from a battery 9V, but can become also from one power supply. The regulation of frequency should become in the 10HZ or little bigger, with to pontesometer TR1 combination with the C1, which we can change the capacity, changing thus and the frequency of oscillator. Bigger frequency means faster speed in ??rolling?? the indicate in the display. M? the TR2 we alter the time where will last the measurement, afterwards the release of S1. With the S2 we make RESET in the display. With the S1, we make departure in the circuit and simultaneously RESET, when start after a circle. ..

PWM controller with PIC18f2455

PWM controller with PIC18f2455

The use of pulse width modulation (PWM) is common for the use of controlling power to a particular electrical device. Motor speed control, LED contrast control, power supplies are some of the example usage of PWM. 18 series PIC always come with a CCP module which is capable of generating PWM. The picture below shows an example of using the capture/compare/pwm (CCP) module to control the LED brightness. PWM duty cycle is set accordingly using the value obtain from the potential meter through the ADC with 5v being the brightness and 0v dimmest for the LED...

A/D converter 16Bit with LCD and PIC18F2550

A/D converter 16Bit with LCD and PIC18F2550

The analog to digital converter (ADC) is a commonly required in most of the projects. Analog voltage measurement can be done using the ADC hardware built in together in a PIC. The picture below show a simple setup for measuring the voltage through the adjustment of the potentiometer. PIC used in this example come with a 10 bit ADC. In the picture the hex value shown is the ADC value acquired from the hardware. After a simple conversion the voltage can be obtain from this value...

8 channel LCD Teperature meter ( RS232 - AT90S2313 )

8 channel LCD Teperature meter ( RS232 - AT90S2313 )

This is the fully featured, jammed packed temperature readout unit. I can measure temperature from up at 8 DS1820 digital temperature sensors all on the same 1-wire bus. That's right only 3 wires are needed to go to all the temperature sensors, GND, VCC and 1-wire data. All sensors will connect to the same cable! Anyone who has used the DS1820's will know that each DS1820 sensor will have a 48bit serial number that is used to address the sensors. With this unit the microcontroller will search the bus automatically for all present DS1820's and record thier serial numbers in memory. You just connect the sensors and go. You dont have to program in serial numbers of each device...

Led Clock using PIC16F84

Led Clock using PIC16F84

Using only 2 capacitors, 3 resistors, 4 seven-segment Display, 1 xtal, 2 switches n.o. and 1 Microcontroller PIC, you can build this Digital Led Clock. you can use common anode or common cathode display, just select the display type. Here is the pinout information: Pin 3 defines the display type. If you will use common cathode display, connect to negative. For common anode, connect to positive. Here is a example circuit:..

68HC11 as a Digital Timer

68HC11 as a Digital Timer

The timer is proposed an effective model for controlling an external load 8A/380V. Equipped with a 68HC11 mu.P associated with an 8 MHz crystal, it can get very precise programmable durations. Two lines are planned: from 0 to 99 seconds and from 0 to 99 minutes. Both displays allow programming in conjunction with a 4-button keypad. They also display the count of elapsed time. The relay output double contact work controls the external load...

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