arduino lcd display clock brands

/* Arduino "Clock" with LCD (20x4) I2C.This I2C LCD backpack contains the PCF8574 port-expanderIC. Beware that this sketch can work with backpacks thatcontains this IC, but may not work with variations.Components:- Arduino Uno- LCD I2C (20x4)Libraries:- LiquidCrystal_I2C libraryCreated on 25 June 2022 by c010rblind3ngineer*/#include LiquidCrystal_I2C lcd(0x27, 20, 4);const int a_sec = 900; // clock second handint Hrs, Mins;int Secs = 0;String AmPm; // to store the string data to display "AM" or "PM"int ampm; // to store user inputint day, d, m, yr;char *DAYS[] = {"Mon", "Tues", "Wed", "Thurs", "Fri", "Sat", "Sun"};char *MONTHS[] = {"Jan", "Feb", "Mar", "Apr", "May", "June","July", "Aug", "Sep", "Oct", "Nov", "Dec"};void setup(){Serial.begin(9600);lcd.init();lcd.backlight();clkInit();}void loop(){//...Display Time to LCD...lcd.setCursor(0, 1);lcd.print("Time: ");printolcd(Hrs);lcd.print(":");printolcd(Mins);lcd.print(":");printolcd(Secs);lcd.print(AmPm);//...Clock starts...Secs++;if (Secs == 60) {Secs = 0;Mins++;}if (Mins == 60) {Mins = 0;Hrs++;}if (Hrs == 13) {Hrs = 1;}if (Hrs == 12 && Mins == 00 && Secs == 00) {if (AmPm == "AM") {AmPm = "PM";}else {AmPm = "AM";d++;reset_dom(m); // reset the day to 1 when the days of the month exceed it"s limit//...Reset LCD row 0 and update date...lcd.setCursor(0, 0);lcd.print(" ");lcd.setCursor(0, 0);lcd.print(DAYS[day]); // mon, tues, wed... etc.lcd.print(", ");printolcd(d);lcd.print(" ");lcd.print(MONTHS[m - 1]);lcd.print(" ");lcd.print(yr);day++;}}delay(a_sec); // delay acts as the clock second hand}///////////////////////////////////////////Initialise the "clock" settings///////////////////////////////////////////void clkInit() {Serial.println("What is the day today? (1 - 7)");Serial.println("\t(1) Monday\n\t(2) Tuesday\n\t(3) Wednesday\n\t(4) Thursday\n\t(5) Friday\n\t(6) Saturday\n\t(7) Sunday");while (Serial.available() == 0) {}; // wait for user inputday = Serial.parseInt(); // store what day is today in integer variable "day"delay(500);Serial.println("\nWhat is today"s date?");Serial.print("Day (1 - 31): ");while (Serial.available() == 0) {}; // wait for user inputd = Serial.parseInt(); // store day in integer variable "d"printoserial(d);Serial.print("\nMonth (1 - 12): ");while (Serial.available() == 0) {}; // wait for user inputm = Serial.parseInt(); // store month in integer variable "m"Serial.print(MONTHS[m - 1]);Serial.print("\nYear (YYYY): ");while (Serial.available() == 0) {}; // wait for user inputyr = Serial.parseInt(); // store year in integer variable "yr"Serial.print(yr);delay(500);Serial.print("\n\n\tToday is ");Serial.print(DAYS[day - 1]);Serial.print(", ");printoserial(d);Serial.print(" ");Serial.print(MONTHS[m - 1]);Serial.print(" ");Serial.print(yr);Serial.print("\n\nIs it - (1)AM or (2)PM ?");while (Serial.available() == 0) {};ampm = Serial.parseInt();delay(500);if (ampm == 1) {AmPm = "AM";Serial.print("\nClock set to AM\n\n");}if (ampm == 2) {AmPm = "PM";Serial.print("\nClock set to PM\n\n");}delay(500);Serial.print("Input Hours (1 - 12) : ");while (Serial.available() == 0) {} // wait till the user inputs dataHrs = Serial.parseInt();printoserial(Hrs);delay(500);Serial.print("\nInput Minutes (0 - 59) : ");while (Serial.available() == 0) {} // wait till the user inputs dataMins = Serial.parseInt();printoserial(Mins);delay(500);Serial.print("\n\n\tClock set to : ");//...Display time to Serial Monitor...printoserial(Hrs);Serial.print(":");printoserial(Mins);Serial.print(AmPm);//... Display Date to LCD...lcd.setCursor(0, 0);lcd.print(DAYS[day - 1]);lcd.print(", ");printolcd(d);lcd.print(" ");lcd.print(MONTHS[m - 1]);lcd.print(" ");lcd.print(yr);}//////////////////////////////////////////////////////////////////////////////To put an extra "0" infront of the variables on the Serial Monitor//////////////////////////////////////////////////////////////////////////////void printoserial(int val){if (val < 10) {Serial.print("0");Serial.print(val);}else {Serial.print(val);}}///////////////////////////////////////////////////////////////////To put an extra "0" infront of the variables on the LCD///////////////////////////////////////////////////////////////////void printolcd(int val){if (val < 10) {lcd.print("0");lcd.print(val);}else {lcd.print(val);}}void reset_dom(int var) {switch (var) {case 1: // Jan - 31 daysif (d == 32) {d = 1;m++;}break;case 2: // Feb - 28 daysif (d == 29) {d = 1;m++;}break;case 3: // March - 31 daysif (d == 32) {d = 1;m++;}break;case 4: // April - 30 daysif (d == 31) {d = 1;m++;}break;case 5: // May - 31 daysif (d == 32) {d = 1;m++;}break;case 6: // June - 30 daysif (d == 31) {d = 1;m++;}break;case 7: // July - 31 daysif (d == 32) {d = 1;m++;}break;case 8: // August - 31 daysif (d == 32) {d = 1;m++;}break;case 9: // September - 30 daysif (d == 31) {d = 1;m++;}break;case 10: // October - 31 daysif (d == 32) {d = 1;m++;}break;case 11: // November - 30 daysif (d == 31) {d = 1;m++;}break;case 12: // December - 31 daysif (d == 32) {d = 1;m++;}break;}}

· Operating voltage: 5V· Alphanumeric character set· 4 lines of 20 characters· Blue Backlight· Module size: 98 x 60 x12mm· Display size: 75 x 25mm· I2C 2-wire connection· Built-in Contrast Adjustment

The code uses a PIR movement detector to turn the LCD display on and off. This Library is able to decode the DCF77 signal even if it contains a massive amount of noise. The library also "auto tunes" the Arduino Quartz crystal in the rare event the DCF77 signal is lost (no backup RTC required). For this Library to work your Arduino must use a Quartz crystal as a timebase not a problem if you build your own Arduino as I have. If you are using an Arduino Uno a Quartz crystal can be added my modding the UNO board. See how to do it here Mod standard Uno

As this clock drives other slave clocks as well as the built in analogue display this row monitors the main decoded display and it detects a jump in the seconds backwards or forwards. These will be shown as fast or slow seconds on Row 2 along with the date and time they were detected. On initial power up there are no fast or slow pulses so Row 2 Slow Pulse will be "0" and the date and time indicates when the clock was first power up and synchronized. The Fast Pulse will also show "0" but the date and time will show as "Never" The only time you would expect to see a Slow or Fast pulse detected is if the DCF77 signal was removed for several days then reconnected or if a leap second is injected (fast pulse)

Row 4 Sig Match - Once locked into the DCF77 signal Udo Klein"s library can predict what the next signal pulse should be. The Signal Match displayed as a percentage shows the quality of the received signal. 100% being a perfect match to the predicted signal.

Row 4 also shows the tuned accuracy of the quartz crystal. Once the clock has run for a number of days the accuracy of the quartz crystal is tuned until it reaches a max accuracy of 1Hz.

The attained accuracy is displayed. This is fully dynamic so the quartz crystal is continually tuned no matter the temperature or age drift of the crystal. Remember this is not the accuracy of the clock but the accuracy of the quartz crystal if the DCF77 signal was to fail.

This project requires a minimum amount of wiring and no soldering. The time keeper is a DS3231 real time clock. The time is displayed on an inexpensive 1602 LCD. Both modules use I2C communications. I2C only use 2 wires per module when connecting to an Arduino. I"m using an Arduino Nano because it fits nicely on a breadboard. The following instructions will work with an Arduino Uno as it has the same pin numbers as the Nano for this project. The other component is the infrared receiver. It allows you to use a common remote controller such as TV remote to set the time just like you would on our smart TV. The infrared receiver only requires one wire to connect it to the Arduino.

The first step is testing the Arduino and wiring it to the breadboard. The steps following that are designed to work independently. Each step has wiring instructions and testing instructions. When I build projects, I wire and test each component to confirm they are working. This helps integrating number of components because know that each work and I can focus on the integration requirements.

This Instructable requires that you have the Arduino IDE installed. You are also required to have the basic skills to download an Arduino sketch program from the links in this project, create a directory for the program (directory name same as the program name). The next steps are to load, view and edit the program in the IDE. Then, upload the program through a USB cable to your Arduino board.

Building a clock with Arduino is easier than you think. All you need to get started is an Arduino prototyping board and some type of display, preferably one with at least eight characters. I will be using an Arduino Uno board with a Sparkfun 16×2 LCD display. To set the time on the Arduino, we will be sending a Unix Timestamp over serial using the Arduino IDE Serial Monitor.

Look at the wiring diagram below to connect the LCD display with the Arduino Uno. It may look a little confusing, but it is very straight forward. Six jumper wires are connected from pins on the display to the Arduino headers. Ground is connected three times on the display; +5v once, and 220Ohms +5v are connected once.

The potentiometer is connected to Ground and +5v with the middle pin connected to the 3rd pin from the left on the display. The potentiometer is used to control the contrast of the display to make the characters readable.

There are two different libraries we will use for this project. One is the LiquidCrystal Library that comes packaged with the Arduino IDE. The second library is the Time Library created by Michael Margolis. As the two names imply, LiquidCrystal will be used to control the display, and Time will be used to keep track of the time.

Congrats on creating your first Arduino Clock! But, now what? Now that you know how to tell time with Arduino, you can create smarter Internet of Everything (IoE) devices that are aware of the time. Automate the blinds in your house to open and close at a certain time of day. Create something with a bang that will really get people’s attention!

This is a very low-power LCD clock, based on an AVR128DA48, capable of running for over three years from a CR2032 button cell, or for ever from a solar cell:

Every minute it also briefly displays the temperature, using the AVR128DA48"s on-chip temperature sensor, and the battery voltage, by using the ADC to read its own supply voltage. There"s also an I2C connection so you can add an external sensor, for example to show the humidity in addition to the other readings.

Although liquid crystal displays (LCDs) are relatively old technology, they still offer several advantages over newer types of display, including low power, low cost, and readability.

I recently bought some Densitron LCD displays on eBay for a few pounds/dollars, and I"d been wanting to try building a low-power clock around them, to see just how low I could get the power consumption. The displays are a standard type, available with compatible pinouts from several manufacturers. They are called static (as opposed to multiplexed), which means that every segment comes to a separate pin on the edge connector. This makes 28 pins for the segments plus three decimal points, a colon, and a common pin, adding up to 33 pins altogether. The displays I"ve found usually have two common pins, and also typically have other special-purpose segments, such as a minus sign, in a 40-pin package.

The displays are usually clear, but when you apply a voltage of about 3.3V between a segment and the common line the segment turns black. The displays I"m using have a reflective backing; they are also available with a translucent backing so you can add a backlight behind them.

There"s one catch; you can"t use a DC voltage to turn on the segments, because this would cause electrolysis to occur which would slowly degrade the display. The solution is to use AC by switching the polarity across the segment at a low frequency; 32Hz is usually recommended. Fortunately this is easy to do in software

Most 40-pin, 33mm row spacing displays should be compatible with this board; here are some I"ve found. These all have 4 digits and 3 decimal points on pins 5 to 27, 29 to 32, and 34 to 37, and commons on 1 and 40, plus a few extra symbols as shown:

Because of the number of interconnections I didn"t fancy prototyping this project by hand, but went straight to designing a PCB in Eagle, and I sent it to PCBWay for manufacture. I tried to make the PCB as general purpose as possible. It caters for any of the displays in the above table; to select which of the extra symbols you want to display you need to fit an 0Ω resistor to the board to act as a link.

Alternatively, if you want to power the clock from a 3V solar cell there are holes to allow you to fit a supercapacitor in place of the coin cell; I used a PowerStor 0.47F 5V one

The PCB also includes a 4-pin JST PH socket, providing an I2C interface compatible with Adafruit"s STEMMA system or the Grove system. You can use this to connect a sensor to the board, for example to show the humidity as well as the time and temperature, or you could use it to make the board an I2C slave so it can be used as an I2C display for other projects.

There"s no multiplexing, so to display a segment pattern we just need to write the appropriate value from the segment array, Char[0] to Char[11], to the port corresponding to the digit. Ports D, C, and A provide eight I/O lines each, so these map in a logical way to the seven segments and decimal point in digits 0 to 2. There"s a slight complexity with digit 3 because Port B only has six I/O lines available, so the segment corresponding to bit 6 is provided by PF5. The colon or other symbol is controlled by PF4.

The clock uses the Real-Time Clock (RTC) peripheral controlled by a 32.768kHz crystal to keep accurate time. The code to set up the RTC is almost identical to my earlier projects Mega Tiny Time Watch [Updated] and Big Time. It is configured as a Periodic Interrupt Timer (PIT), generating a regular interrupt. In this project I"ve used a divisor of 512, which divides down the 32.768kHz crystal to give 64 interrupts a second.

The interrupt service routine first toggles all the I/O lines connected to the LCD segments, and the common connections. Every 32 calls, or every half second, it calculates the current time, and checks whether the buttons are pressed. If the MINS or HRS buttons are pressed it advances the time by a minute or an hour respectively. It then calls the routine DisplayTime() to update the time, or at the end of each minute it calls DisplayVoltage() to display the battery voltage for three seconds, followed by DisplayTemp() to display the temperature for three seconds:

DisplayTime() copies the digits representing the current time to the corresponding output ports, specified by Digit[0] to Digit[3]. It also flashes the colon:

Unlike earlier AVR microcontrollers, where you had to calibrate the temperature sensor, the AVR DA and DB series have been calibrated during manufacture and contain calibration parameters in ROM. The temperature display is therefore pretty accurate without any additional calibration.

The processor spends most of its time in power-down sleep mode, to save power, and is woken up by the 64Hz interrupt from the Real-Time Clock peripheral. I measured the average power consumption at 3.3V for four different clock frequencies:

Usually you"d expect the power consumption to increase with processor clock frequency, so at first sight these figures are puzzling. The explanation is that at higher clock frequencies the time taken to execute the interrupt service routine is shorter, allowing the processor to spend a higher proportion of the time asleep.

The 32.768kHz external crystal oscillator has a low-power mode, and selecting this reduced the average power consumption with a 24MHz clock from 9.5µA to 7.3µA. The AVR128DA48 datasheet doesn"t seem to mention any downside to choosing the low-power mode, so I used this setting.

A CR2032 coin cell has a typical capacity of 225 mAh, so with a consumption of 7.3µA the expected battery life of the clock is 225/0.0073/24/365 or about 3.5 years.

With a 0.47F supercapacitor you can expect a current of 0.47A for 1 second. This gives an expected life of 0.47/7.3x10‑6/60/60 or about 18 hours, which I confirmed by testing it. This should be sufficient to keep the clock running overnight with a suitable solar cell providing power during daylight.

Pressing the MINS button resets the seconds to zero; this is designed so you can set the clock to the precise second, such as from a radio timecode. To do this, set the minutes to the current minute, and at the timecode at the end of the minute step the minutes on by one.

The HRS button doesn"t affect the seconds and minutes timing; this is designed to allow you to switch between Standard Time and Daylight Saving Time without affecting the clock setting.

Make a UPDI programmer from an Arduino Uno, or other ATmega328P-based board, as described in Make UPDI Programmer, and set the Programmer option to "jtag2updi".

I"m very new to Arduino, but not to electronics (which I"ve been doing for 30+ years). I"ve been working from the book Beginning Arduino by Michael McRoberts and I"ve had very few problems so far. I"ve just started the chapter on LCD displays and I"m trying the Basic LCD Control project. I am using a brand new display that I bought from Rapid Electronics (UK):

Winstar - WH1602B-YYH-JT - Winstar WH1602B-YYH-JT 16x2 LCD Display Yellow/green LED Backlight - A 16 x 2 LCD display that has a transflective type 6 o"clock

I had to solder a header to it to use it on a breadboard. I took ESD precautions and I"ve tested that there are no shorts and that all pins are connected OK. The thing is, when I try out the program, absolutely nothing happens - the backlight doesn"t even come on. I am aware of errors both in the book diagram (where R/W is not connected to GND) and in the program which showed a compile error initially, but I found a fix on this forum. I have checked the connections and code over and over again, but with no mistakes found. I"ve checked that everything that should be at 0V/+5V actually is. I"ve even checked that all of my Arduino digital pins are still working using a simple LED flash program.

Let’s use the ESP32 to display the date and time on the screen like a normal alarm clock so that the alarm can ring at a specified time. To make a “wake up alarm clock,” we need to place the extension button (for stopping the alarm) separately from the alarm clock body. The idea is that you would have to get up from bed and walk over to where the extension button is to turn off the alarm.

For microcomputers such as Arduino, it’s common to be able to get the elapsed time upon booting up the program. However, the time you get is often not very accurate, as the elapsed time will reset when the power is turned off.

With ESP32, you can connect to the internet via Wi-Fi to get the date and time periodically from an NTP server on the internet and set it on ESP32. However, some microcomputers, such as Arduino Uno, don’t have an internet connection function, so it would be useful to have a mechanism that could handle date and time easier.

That’s why an IC called “RTC” (Realtime Clock) is commonly used. An RTC is an IC that makes time tick based on elements that are periodically signaled. In addition, by connecting it to an external power supply such as a battery, time can be maintained even while the power to the microcomputer is switched off.

Since the clock is used to check the current date and time, it’s necessary to display the date and time in an easy-to-understand manner. The following devices are used to display the date and time.

There are different libraries and different programming methods depending upon the device. It also depends upon whether it’s suitable for what you want to make. For example, a 7-segment LED is suitable for displaying only numbers at a low cost, but won’t be suitable for a detailed display. Among the above, the graphic LCD display is the most versatile and can be used for many different projects, so we decided to use it for today’s demonstration.

There are various types of LCD display modules out there, but for today’s project, we’ll be using a controller mount called “ILI9341” and be using an SPI connection (Photo 2). In addition, LCD displays are commonly sold in 2.2-inch/ 2.4-inch /2.8-inch sizes, so adjust accordingly to the type of work you’re doing.

Since it’s an alarm clock, having a sound ring out at a specified time is a necessity. You can connect a buzzer to the ESP32 to produce a single sound, but if you’d like, you could also use your own favorite sound. For that, we’ll be using a module called “DFPlayer Mini” that can play back any MP3 data (Photo 3).

Additionally, install a font file to display the time in large characters. If you download and unzip the following zip file, you’ll get a file called “FreeSans40pt7b.h.”

Rewrite lines 5 to 9 in the same way as the alarm clock itself. However, on the 7th line, specify the IP address assigned to the extension unit. In addition, specify the IP address of the alarm clock in the “Main console IP address” on the 9th line.

If you’ve ever attempted to connect an LCD display to an Arduino, you’ve probably noticed that it uses a lot of Arduino pins. Even in 4-bit mode, the Arduino requires seven connections – half of the Arduino’s available digital I/O pins.

The solution is to use an I2C LCD display. It only uses two I/O pins that are not even part of the digital I/O pin set and can be shared with other I2C devices.

As the name suggests, these LCDs are ideal for displaying only characters. A 16×2 character LCD, for example, can display 32 ASCII characters across two rows.

At the heart of the adapter is an 8-bit I/O expander chip – PCF8574. This chip converts the I2C data from an Arduino into the parallel data required for an LCD display.

If you have multiple devices on the same I2C bus, you may need to set a different I2C address for the LCD adapter to avoid conflicting with another I2C device.

An important point to note here is that several companies, including Texas Instruments and NXP Semiconductors, manufacture the same PCF8574 chip. And the I2C address of your LCD depends on the chip manufacturer.

So the I2C address of your LCD is most likely 0x27 or 0x3F. If you’re not sure what your LCD’s I2C address is, there’s an easy way to figure it out. You’ll learn about that later in this tutorial.

Now we are left with the pins that are used for I2C communication. Note that each Arduino board has different I2C pins that must be connected correctly. On Arduino boards with the R3 layout, the SDA (data line) and SCL (clock line) are on the pin headers close to the AREF pin. They are also referred to as A5 (SCL) and A4 (SDA).

After wiring the LCD, you will need to adjust the contrast of the LCD. On the I2C module, there is a potentiometer that can be rotated with a small screwdriver.

Now, turn on the Arduino. You will see the backlight light up. As you turn the potentiometer knob, the first row of rectangles will appear. If you have made it this far, Congratulations! Your LCD is functioning properly.

Before you can proceed, you must install the LiquidCrystal_I2C library. This library allows you to control I2C displays using functions that are very similar to the LiquidCrystal library.

As previously stated, the I2C address of your LCD depends on the manufacturer. If your LCD has a PCF8574 chip from Texas Instruments, its I2C address is 0x27; if it has a PCF8574 chip from NXP Semiconductors, its I2C address is 0x3F.

If you’re not sure what your LCD’s I2C address is, you can run a simple I2C scanner sketch that scans your I2C bus and returns the address of each I2C device it finds.

However, before you upload the sketch, you must make a minor change to make it work for you. You must pass the I2C address of your LCD as well as the display dimensions to the LiquidCrystal_I2C constructor. If you’re using a 16×2 character LCD, pass 16 and 2; if you’re using a 20×4 character LCD, pass 20 and 4.

The next step is to create an object of LiquidCrystal_I2C class. The LiquidCrystal_I2C constructor accepts three inputs: I2C address, number of columns, and number of rows of the display.

In the setup, three functions are called. The first function is init(). It initializes the interface to the LCD. The second function is clear(). This function clears the LCD screen and positions the cursor in the upper-left corner. The third function, backlight(), turns on the LCD backlight.

The function setCursor(2, 0) is then called to move the cursor to the third column of the first row. The cursor position specifies where you want the new text to appear on the LCD. It is assumed that the upper left corner is col=0 and row=0.

There are many useful functions you can use with LiquidCrystal_I2C Object. Some of them are listed below:lcd.home() function positions the cursor in the upper-left of the LCD without clearing the display.

lcd.scrollDisplayRight() function scrolls the contents of the display one space to the right. If you want the text to scroll continuously, you have to use this function inside a for loop.

lcd.scrollDisplayLeft() function scrolls the contents of the display one space to the left. Similar to the above function, use this inside a for loop for continuous scrolling.

lcd.display() function turns on the LCD display, after it’s been turned off with noDisplay(). This will restore the text (and cursor) that was on the display.

If you find the default font uninteresting, you can create your own custom characters (glyphs) and symbols. They come in handy when you need to display a character that isn’t in the standard ASCII character set.

The CGROM stores the font that appears on a character LCD. When you instruct a character LCD to display the letter ‘A’, it needs to know which pixels to turn on so that we see an ‘A’. This data is stored in the CGROM.

CGRAM is an additional memory for storing user-defined characters. This RAM is limited to 64 bytes. Therefore, for a 5×8 pixel LCD, only 8 user-defined characters can be stored in CGRAM, whereas for a 5×10 pixel LCD, only 4 can be stored.

Creating custom characters has never been easier! We’ve developed a small application called Custom Character Generator. Can you see the blue grid below? You can click on any pixel to set or clear that pixel. And as you click, the code for the character is generated next to the grid. This code can be used directly in your Arduino sketch.

After including the library and creating the LCD object, custom character arrays are defined. The array consists of 8 bytes, with each byte representing a row in a 5×8 matrix.