This project describes how to make a digital voltmeter using a PIC microcontroller. A HD44780 based character LCD is used to display the measured voltage. The PIC microconotroller used in this project is PIC16F688 that has 12 I/O pins out of which 8 can serve as analog input channels for the in-built 10-bit ADC. The voltage to be measured is fed to one of the 8 analog channels. The reference voltage for AD conversion is chosen to be the supply voltage Vdd (+5 V). A resistor divider network is used at the input end to map the range of input voltage to the ADC input voltage range (0-5 V). The technique is demonstrated for input voltage ranging from 0-20 V, but it can be extended further with proper selection of resistors and doing the math described below.
PIC16F688 Digital Voltmeter - [Link]
HD44780 based character LCDs require at least 6 I/O lines from microcontroller to display data. Therefore, they are not suitable for low-pin microcontrollers like PIC12F series microchips. In this project, I am going to show how to drive an HD44780 based LCD display with only 3 pins of a microcontroller. I am going to demonstrate it with PIC12F683 microchip. The character data and command from the microcontroller is transferred serially to a shift register (74HC595), and the parallel output from the shift register is fed to LCD pins.
3-Wire Serial LCD using a Shift Register - [Link]
This project is a simple Min/Max Thermometer based on Arduino. It uses LM35DZ temperature sensor that has three pins, +5V, ground and a variable voltage output to indicate the temperature. Sensor is plugged into breadboard and wired the output straight to the Arduino’s analogue input 0. The display used in this project is a Displaytech 162B which is a HD44780 LCD controller compatible device. Check details on code on the link below.
A Simple Arduino LCD Min/Max Thermometer – [Link]
This is a clock based on AVR Attiny2313 and works in 24 hour period. The time is displayed in the format “hh: mm: ss” on the alphanumeric display of size 16 x 2 (columns x rows) with driver HD44780.
Clock based on the chip AVR Attiny2313 – [Link]
This project is an AVR spectrum analyzer based on Atmega8 AVR microcontroller an operational amplifier and a few other components. It uses HD44780 compatible LCD or VFD and supports following displays: 16×2, 20×2, 24×2, 20×4.
AVR acoustic spectrum analyzer - [Link]
In Part 1 of this tutorial learn how to drive HD44780 LCD displays using plain dip switches and some other components on a breadboard. Characters are written on LCD by controlling data bits using dip switches. That’s a nice way to learn how HD44780 displays are controlled. In Part 2 learn how to drive the same LCD using an Atmega8 microcontroller and write some code to instuct LCD. In this part a AVR 28 pin Development Board is used. Check tutorial on the links below.
This simple design uses the 20 pin ATTiny2313 microcontroller to measure frequencies from 1Hz to over 2MHz. The frequency is displayed on a standard HD44780 16×2 LCD. A bright white text, blue backlit LCD is included with the kit. The device requires a regulated 5V power supply. [via]
FunCount Frequency Counter – [Link]
This page describes how to communicate with HD44780-based LCDs (Liquid Crystal Displays) using an Atmel AVR microcontroller.In many microcontroller applications some sort of display is needed to present information and status of the controller to the user. Although a few LEDs can provide a lot of information, a more advanced display is sometimes needed. A solution which is quite often seen is using a HD44780-based character LCD module. These modules come in various configurations from one line of 8 chars to 4 lines of 40 characters. [via]
Using HD44780-based LCDs with AVR microcontrollers – [Link]
Bascom can handle the two main types of liquid-crystal displays: alphanumeric and graphic. For the time being we will concern ourselves with the most common alphanumeric type. This type of LCD can display characters, numbers and special characters. The most common type of alphanumeric LCD uses a Hitachi HD44780 as display controller. When you are uncertain about what type of display you are holding in your hands, simply look at the chip designations on the back. If one of these says HD44780 you’re safe. [via]
Bascom and AVR, Using an LCD - [Link]