It's easy to make a simple digital voltmeter using an Arduino and 16x2 liquid crystal display (LCD).It's relatively simple to use an Arduino to measure voltages. The Arduino has several analog input pins that connect to an analog-to-digital converter (ADC) inside the Arduino. The Arduino ADC is a ten-bit converter, meaning that the output value will range from 0 to 1023.
We will obtain this value by using the analogRead function. If you know the reference voltage-in this case we will use 5 V-you can easily calculate the voltage present at the analog input.To display the measured voltage, we will use a liquid crystal display (LCD) that has two lines of 16 characters. LCDs are widely used to display data by devices such as calculators, microwave ovens, and many other electrical appliances.This project will also show you how to measure voltages above the reference voltage by using a voltage divider.Experiment 1In this experiment, we will make digital voltmeter capable of measuring up to 5V using an Arduino board and a 16x2 LCD.Hardware Required. 1 x Arduino Mega2560. 1x LCD (Liquid Crystal Display). 1x 5 kohm potentiometer.
When the Input voltage is 30V (max) the voltage across 20K ohm resistor becomes 5V which is feedback to the analog pin RA2 of the PIC Microcontroller. The voltage across.47 ohm resistor is also feedback to the analog pin RA3 via 100K ohm resistor. 5.1V Zener Diode is added in parallel to these analog input pins to protect PIC from over voltages. Dual Channel Digital Volt Meter. Two digital volt meter chips, ICL7135 are interfacing to the 89S52 microcontroller. The ICL7135 is a 4.5 digital volt meter chip using the integrating method. The input range is +/-1.9999V with 100 uV sensitivity. The ICL7135 provides a multiplexed BCD output and strobe signal (STRB).
1x breadboard. female connectors. jumper wiresWiring DiagramThe 16x2 LCD used in this experiment has a total of 16 pins. As shown in the table below, eight of the pins are data lines (pins 7-14), two are for power and ground (pins 1 and 16), three are used to control the operation of LCD (pins 4-6), and one is used to adjust the LCD screen brightness (pin 3). The remaining two pins (15 and 16) power the backlight. The ATMEGA internal ADC has 3 valuable possibilies for this project:first it has in internal reference of 2.56 V and this makes your meter not depending on the 5 V supply.second it allows for differntial ADC conversion which allows for measuring also negativ voltagesthird it has a build in amplifier x10 which could be used for low voltages.For voltages higher than the reference voltage you can use any voltage divider, with R2 being 10 kohm (because this is best for the internal ADC). The reading is the multiplication of ADC result by a cal constant, which have to fixed of a one time calibration with a second voltage meter.I would recomend a capacitor on the input of ADC to filter AC voltages to achieve more stable readings.
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DescriptionThe PIC16F876A is a micro controler divise. 28-pin Low Power Microcontroller.
Flash Program Memory: 8192 bytes EEPROM Data Memory: 256 bytes. SRAM Data Memory: 368 bytes.
I/O Pins: 22. Timers: Two 8-bit / One 16-bit n.A/D Converter: 10-bit Five Channel.PWM: 10-bit Two Modules. SSP: SPI and I²C Support. USART: Full Duplex with 9-bit Address Detection.
External Oscillator: up to 20MHz.FEATURES of PIC16F876A:High-Performance RISC CPU:. Operating speeds from DC – 20 MHz. Interrupt capability.
8-level deep hardware stackLow-Power Features:. Standby Current:– 100 nA @ 2.0V, typical.
Operating Current:– 12 μA @ 32 kHz, 2.0V, typical– 120 μA @ 1 MHz, 2.0V, typical. Watchdog Timer Current:– 1 μA @ 2.0V, typical. Timer1 Oscillator Current:– 1.2 μA @ 32 kHz, 2.0V, typical. Dual-speed Internal Oscillator:– Run-time selectable between 4 MHz and48 kHz– 4 μs wake-up from Sleep, 3.0V, typical.
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