arduino lcd display power consumption manufacturer

Guys, I have measured my LCD current drawn( only at the Vcc pin). And it is ard 1mA.. Is this in the normal range? And when I measured the backlight alone, it is ard 6mA.. Normal?

Without a datasheet for your specific LCD module it is hard to tell if your values are normal but as far as the LCD current of 1 mA is concerned that seems possible.

Without knowing how your backlight is powered and what type of meter you are using we really can"t evaluate your 6 mA reading except to speculate on why it is so low. Nick could be on the right track with the observation that the 6 mA reading "may reflect the characteristics of the meter more than the power consumed" (when you substitute the term "current" for "power"). This isn"t much of a problem when measuring non pulsating DC or pure sinusoidal AC but can be a big problem when measuring anything else.

We have much merriment here when people refer to a "9v battery" if they mean the common "PP3" or "smoke alarm battery". It will not run an Arduino for very long at all.

You do not want to power the Arduino by "Vin" or the "barrel jack". The on-board regulator is not very capable and you are just wasting four volts out of nine. Four Ni-Mh "AA" cells in a holder would be far more appropriate, connected to the "5V" pin.

Now the backlight on the LCD draws about 20 mA (in most cases) while the LCD itself draws less than 1 mA. It will in fact draw only half of that if you correct a common mistake and remove the connection from the contrast potentiometer to 5 V, leaving it only connected to pin 3 and ground.

The Arduino itself however consumes as much or more power than the backlight, particularly a UNO or Nano etc. with a USB to serial chip. The Pro Mini does not have this USB to serial chip (you have to connect an adapter to program it) so is much better in this respect.

Typically the LCD driver draws around 1mA or 1.1mA, not counting the external contrast voltage divider. They are fairly consistent between suppliers, as they are mostly based on an (originally) Hitachi-designed chip set HD44780/HD44100.

If you’ve ever tried to connect an LCD display to an Arduino, you might have noticed that it consumes a lot of pins on the Arduino. Even in 4-bit mode, the Arduino still requires a total of seven connections – which is half of the Arduino’s available digital I/O pins.

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

True to their name, these LCDs are ideal for displaying only text/characters. A 16×2 character LCD, for example, has an LED backlight and can display 32 ASCII characters in two rows of 16 characters each.

If you look closely you can see tiny rectangles for each character on the display and the pixels that make up a character. Each of these rectangles is a grid of 5×8 pixels.

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.

In addition, there is a jumper on the board that supplies power to the backlight. To control the intensity of the backlight, you can remove the jumper and apply external voltage to the header pin that is marked ‘LED’.

If you are using multiple devices on the same I2C bus, you may need to set a different I2C address for the LCD adapter so that it does not conflict with another I2C device.

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

So your LCD probably has a default I2C address 0x27Hex or 0x3FHex. However it is recommended that you find out the actual I2C address of the LCD before using it.

Connecting an I2C LCD is much easier than connecting a standard LCD. You only need to connect 4 pins instead of 12. Start by connecting the VCC pin to the 5V output on the Arduino and GND to ground.

Now we are left with the pins which are used for I2C communication. Note that each Arduino board has different I2C pins that must be connected accordingly. 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 known as A5 (SCL) and A4 (SDA).

After wiring up the LCD you’ll need to adjust the contrast of the display. On the I2C module you will find a potentiometer that you can rotate with a small screwdriver.

Plug in the Arduino’s USB connector to power the LCD. You will see the backlight lit up. Now as you turn the knob on the potentiometer, you will start to see the first row of rectangles. If that happens, Congratulations! Your LCD is working fine.

To drive an I2C LCD you must first install a library called LiquidCrystal_I2C. This library is an enhanced version of the LiquidCrystal library that comes with your Arduino IDE.

The I2C address of your LCD depends on the manufacturer, as mentioned earlier. If your LCD has a Texas Instruments’ PCF8574 chip, its default I2C address is 0x27Hex. If your LCD has NXP Semiconductors’ PCF8574 chip, its default I2C address is 0x3FHex.

So your LCD probably has I2C address 0x27Hex or 0x3FHex. However it is recommended that you find out the actual I2C address of the LCD before using it. Luckily there’s an easy way to do this, thanks to the Nick Gammon.

But, before you proceed to upload the sketch, you need to make a small change to make it work for you. You must pass the I2C address of your LCD and the dimensions of the display to the constructor of the LiquidCrystal_I2C class. If you are using a 16×2 character LCD, pass the 16 and 2; If you’re using a 20×4 LCD, pass 20 and 4. You got the point!

First of all an object of LiquidCrystal_I2C class is created. This object takes three parameters LiquidCrystal_I2C(address, columns, rows). This is where you need to enter the address you found earlier, and the dimensions of the display.

In ‘setup’ we call three functions. The first function is init(). It initializes the LCD object. The second function is clear(). This clears the LCD screen and moves the cursor to the top left corner. And third, the backlight() function turns on the LCD backlight.

After that we set the cursor position to the third column of the first row by calling the function lcd.setCursor(2, 0). The cursor position specifies the location where you want the new text to be displayed on the LCD. The upper left corner is assumed to be col=0, row=0.

There are some useful functions you can use with LiquidCrystal_I2C objects. Some of them are listed below:lcd.home() function is used to position 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 above function, use this inside a for loop for continuous scrolling.

If you find the characters on the display dull and boring, you can create your own custom characters (glyphs) and symbols for your LCD. They are extremely useful when you want to display a character that is not part of the standard ASCII character set.

CGROM is used to store all permanent fonts that are displayed using their ASCII codes. For example, if we send 0x41 to the LCD, the letter ‘A’ will be printed on the display.

CGRAM is another memory used to store user defined characters. This RAM is limited to 64 bytes. For a 5×8 pixel based LCD, only 8 user-defined characters can be stored in CGRAM. And for 5×10 pixel based LCD only 4 user-defined characters can be stored.

Creating custom characters has never been easier! We have created a small application called Custom Character Generator. Can you see the blue grid below? You can click on any 5×8 pixel to set/clear that particular 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 the library is included and the LCD object is created, custom character arrays are defined. The array consists of 8 bytes, each byte representing a row of a 5×8 LED matrix. In this sketch, eight custom characters have been created.

LCD (Liquid Crystal Displays) have two options or display modes.Positive mode (dark characters on a light colored background) and negative mode (lighter colored characters on a darker background).

Please see Fig.1: Yellow green STN (Super Twisted Nematic) display, the background of yellow green is lighter than dark blue characters. It is a positive mode. Fig. 2 is a blue STN display, its background of blue is darker than the white characters.It is negative mode.

Positive mode displays have the advantage of their lighter background and no backlights are needed. They normally use transflective or reflective polarizers and have lower power consumption. They can be seen with ambient light.

Negative mode displays need backlit in order to be seen. They normally use transmissive polarizers. They have better contrast and wider viewing angles in the indoor dim environment. The readability is much better than positive displays.

But under bright ambient light or even under direct sunlight, the displays will be easily washed out. In order to be seen under the bright surrounding light, the backlight brightness has to be increased to over 800 nits. The sunlight readable displays consume much power.

Of course, we can always use LED backlight in the LCD module with fewer LED chips and turn off LED backlight when not use to save power. When can also add transflective polarizer to some negative LCDs to make it sunlight readable, but the contrast will be compromised.

Positive and negative mode concept is not only limited to monochrome LCD displays (LCD panels, character LCDs, graphic LCDs etc.), it also uses for color displays, or even other display technologies.  We will categorize the displays as below,

Character LCD modules (Alphanumeric LCD display modules) with character sets: 8×1 LCD display, 8×2 LCD display, 16×1 LCD display, 16×2 LCD display, 16×4 LCD display, 20×2 LCD display, 20×4 LCD display, 24×2 LCD display, 40×2 LCD display, 40×4 LCD display. COB (Chip on Board) bonded, 4 or 8 bits parallel, SPI, I2C interface

Graphic LCD modules with dot matrix sets 122×32, graphic LCD display, 128×64 graphic LCD display, 192×48 graphic LCD display,192×64 graphic LCD display,240×64 graphic LCD display,240×128 graphic LCD display,240×160 graphic LCD display with different color LED backlights, with COB and COG (Chip on Glass) assembling technologies

Monochrome and Color Graphic OLED modules with dot matrix sets 128×32 graphic OLED display,128×64 graphic OLED display, 128×96 graphic OLED display, 160×128 graphic OLED display, 128×128 graphic OLED display, 256×65 graphic OLED display

Full Color TN and IPS displays with panel sizes: 1.3”IPS display, 1.44” TN display, 1.5” IPS display, 1.77”TN and IPS displays, 2.0” TN and IPS displays, 2.2” IPS display, 2.35” IPS display, 2.4” TN and IPS displays, 2.8” TN and IPS displays, 3.5” TN and IPS displays, 4.3” TN display, 5.0” TN and IPS display, 7.0” TN and IPS display, 10.1” IPS display with medium and high brightness (sunlight readable), with parallel, SPI, RGB, LVDS, MIPI interfaces.

Energy efficiency is crucial for future technologies. We need to make our products more power efficient to reduce the stress we put on the environment. Consumers demanding wireless products without bulky cables is another reason to reduce power. Hardware engineers developing IoT projects are struggling to stay within the power budget where the display often is the main problem. To meet these challenges there is a huge demand for ultra-low power IoT displays. In this article, we summarize the three most common low energy displays from a power perspective.

Reflective LCD displays, such as 7 segment displays, have been around for a long time. We recognize them from all kinds of household appliances including thermometers, ovens, watches, toys and medical devices. Until recently, LCD has been the only option for low power but now two alternative technologies exist on the market; the E Ink display based on electrophoresis and the Rdot display based on electrochromism, both offering features that LCD is lacking.

In this article, we investigate E Ink, Reflective LCD and the Rdot Display from a power perspective. All these technologies are categorized as reflective displays. Reflective displays are essentially required for ultra low power applications since emitting light is very power consuming (read more about reflective, transflective, and transmissive displays here). We want to clarify that displays from different manufacturers have slightly different energy consumption, and the data presented here is an average from the suppliers with the most energy efficient displays.

Before we go too deep it is important to understand the driving requirements of each display technology. Reflective LCD displays need an active driver that varies the polarity of the voltage across the pixel in a frequency of about 60Hz. E Ink, on the other hand, doesn"t need any active control once the display has been updated, this feature is often referred to as bistability. Rdot Displays is somewhere in between LCD and E Ink; once the display has been switched the controller can go idle for about 15 minutes (there exist versions that can be idle for up to 24 hours as well). We usually call this phenomenon "semi-bistability". After this time a small refresh pulse is required to maintain the state. For E Ink and Rdot, energy is only required during switching and updating while no energy is consumed during idle state. Typically, the energy required for a full switch on an E Ink display is about 7 to 8mJ/cm2. The corresponding number for the Rdot display is about 1mJ/cm2 with the addition of 0,25mJ/cm2 every 15-60 minutes. LCD continuously consumes about 6µW/cm2.

Followed by the different driving characteristics of the displays, we need to look into how often the display is updated to truly understand which display is the most energy efficient for your specific application. This is done by calculating the average power as a function of the number of switches per day. As seen in the diagram the E Ink display is the most power effective choice if the application is switching less than seven times a day. Between 4 and 600 switches, the Rdot display is the most energy efficient choice. If the display switches more than 600 times a day reflective LCD would be the best option from a power perspective.

To summarize the findings we can conclude that the Rdot display is the most power efficient choice if you need a display that is supposed to switch 4-600 times a day. However, we need to remember that there might be other features to take into consideration as well. For example, the Rdot display is flexible in its standard appearance and can be offered in multiple different colors without additional cost.

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 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.

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".

The lcd.begin(16,2) command set up the LCD number of columns and rows. For example, if you have an LCD with 20 columns and 4 rows (20x4) you will have to change this to lcd.begin(20x4).

The lcd.print("--message--") command print a message to first column and row of lcd display. The "message" must have maximum length equal to lcd columns number. For example, for 16 columns display max length is equal with 16 and for 20 columns display max length is equal with 20.

Thelcd.setCursor(0,1) command will set cursor to first column of second row. If you have an LCD 20x4 and you want to print a message to column five and third row you have to use: lcd.setCursor(4,2).

Try downloading the codebender plugin and clicking on the Run on Arduino button to program your Arduino with this sketch. And that"s it, you"ve programmed your Arduino board!

In this Arduino tutorial we will learn how to connect and use an LCD (Liquid Crystal Display)with Arduino. LCD displays like these are very popular and broadly used in many electronics projects because they are great for displaying simple information, like sensors data, while being very affordable.

You can watch the following video or read the written tutorial below. It includes everything you need to know about using an LCD character display with Arduino, such as, LCD pinout, wiring diagram and several example codes.

An LCD character display is a unique type of display that can only output individual ASCII characters with fixed size. Using these individual characters then we can form a text.

If we take a closer look at the display we can notice that there are small rectangular areas composed of 5×8 pixels grid. Each pixel can light up individually, and so we can generate characters within each grid.

The number of the rectangular areas define the size of the LCD. The most popular LCD is the 16×2 LCD, which has two rows with 16 rectangular areas or characters. Of course, there are other sizes like 16×1, 16×4, 20×4 and so on, but they all work on the same principle. Also, these LCDs can have different background and text color.

It has 16 pins and the first one from left to right is the Groundpin. The second pin is the VCCwhich we connect the 5 volts pin on the Arduino Board. Next is the Vo pin on which we can attach a potentiometer for controlling the contrast of the display.

Next, The RSpin or register select pin is used for selecting whether we will send commands or data to the LCD. For example if the RS pin is set on low state or zero volts, then we are sending commands to the LCD like: set the cursor to a specific location, clear the display, turn off the display and so on. And when RS pin is set on High state or 5 volts we are sending data or characters to the LCD.

Next comes the R/W pin which selects the mode whether we will read or write to the LCD. Here the write mode is obvious and it is used for writing or sending commands and data to the LCD. The read mode is used by the LCD itself when executing the program which we don’t have a need to discuss about it in this tutorial.

Next is the E pin which enables the writing to the registers, or the next 8 data pins from D0 to D7. So through this pins we are sending the 8 bits data when we are writing to the registers or for example if we want to see the latter uppercase A on the display we will send 0100 0001 to the registers according to the ASCII table. The last two pins A and K, or anode and cathode are for the LED back light.

After all we don’t have to worry much about how the LCD works, as the Liquid Crystal Library takes care for almost everything. From the Arduino’s official website you can find and see the functions of the library which enable easy use of the LCD. We can use the Library in 4 or 8 bit mode. In this tutorial we will use it in 4 bit mode, or we will just use 4 of the 8 data pins.

We will use just 6 digital input pins from the Arduino Board. The LCD’s registers from D4 to D7 will be connected to Arduino’s digital pins from 4 to 7. The Enable pin will be connected to pin number 2 and the RS pin will be connected to pin number 1. The R/W pin will be connected to Ground and theVo pin will be connected to the potentiometer middle pin.

We can adjust the contrast of the LCD by adjusting the voltage input at the Vo pin. We are using a potentiometer because in that way we can easily fine tune the contrast, by adjusting input voltage from 0 to 5V.

Yes, in case we don’t have a potentiometer, we can still adjust the LCD contrast by using a voltage divider made out of two resistors. Using the voltage divider we need to set the voltage value between 0 and 5V in order to get a good contrast on the display. I found that voltage of around 1V worked worked great for my LCD. I used 1K and 220 ohm resistor to get a good contrast.

There’s also another way of adjusting the LCD contrast, and that’s by supplying a PWM signal from the Arduino to the Vo pin of the LCD. We can connect the Vo pin to any Arduino PWM capable pin, and in the setup section, we can use the following line of code:

It will generate PWM signal at pin D11, with value of 100 out of 255, which translated into voltage from 0 to 5V, it will be around 2V input at the Vo LCD pin.

First thing we need to do is it insert the Liquid Crystal Library. We can do that like this: Sketch > Include Library > Liquid Crystal. Then we have to create an LC object. The parameters of this object should be the numbers of the Digital Input pins of the Arduino Board respectively to the LCD’s pins as follow: (RS, Enable, D4, D5, D6, D7). In the setup we have to initialize the interface to the LCD and specify the dimensions of the display using the begin()function.

The cursor() function is used for displaying underscore cursor and the noCursor() function for turning off. Using the clear() function we can clear the LCD screen.

In case we have a text with length greater than 16 characters, we can scroll the text using the scrollDisplayLeft() orscrollDisplayRight() function from the LiquidCrystal library.

We can choose whether the text will scroll left or right, using the scrollDisplayLeft() orscrollDisplayRight() functions. With the delay() function we can set the scrolling speed.

So, we have covered pretty much everything we need to know about using an LCD with Arduino. These LCD Character displays are really handy for displaying information for many electronics project. In the examples above I used 16×2 LCD, but the same working principle applies for any other size of these character displays.

I hope you enjoyed this tutorial and learned something new. Feel free to ask any question in the comments section below and don’t forget to check out my full collection of 30+ Arduino Projects.

An easy way to add a simple visual interface to your project is by using an LCD Nanoshield. With it, you can display two lines of text with up to 16 characters. That allows you to show text messages or sensor data to the user, for example.

The internal LCD controller is compatible with the HD44780 chip from Hitachi, a de facto standard in the market for this kind of LCD. This is the same standard used in the LCD library that comes with the Arduino IDE.

The easiest way to use the LCd Nanoshield with an Arduino is to use the Base Board Uno or the Base Board L Uno. You just need to snap the boards together and upload our sample code to verify it"s working (see the code samples section below). This type of connection can be used with Arduino UNO, Mega R3, Duemilanove, and similar boards (contact us if you have questions about compatibility with other versions). The picture below shows how the final assembly looks like.

It is also possible to connect the LCd Nanoshield to our Arduino-compatible microcontroller board, the Base Boarduino. The connection is done in the same way as with the Base Board, as shown in the picture below. You just need to snap the boards together and upload our sample code to verify it"s working (see the code samples section below).

By using the Mini Terminal Nanoshield, it is possible to securely connect the LCD Nanoshield to an Arduino equipped with a Base Board or to a Base Boarduino. This connection uses only five wires, and is useful when the LCD needs to be mounted away from the Base Board – for instance when if must be mounted on a panel or case. The diagram below shows how to make that connection.

The LCD is equipped with a backlight that can be controlled via software by using the backlight() and noBacklight() methods in our Nanoshield_LCD software library.

Note: with the backlight on, the power consumption of the board is relatively high, and the voltage regulator can get quite hot when the system is powered from an external power supply. Don"t worry however, since the board and the components were designed to operate with much higher temperatures without a risk of overheating (but probably you fingers weren"t, so beware). For applications where the ambient temperature is consistently higher than 50ºC and there is no airflow, we recommend use of an external power supply with a maximum voltage of 9V, or our PowerLDO Nanoshield.

Power supply: the board power is supplied via the VIN and VCC pins: VIN is optional but VCC is required. The recommended voltage range for the VIN pin is 7 to 12V (absolute maximum of 20V); the range for the VCC pin is 4.5 to 5.5V (5V typical). When there is power available in both pins, the VIN pin has priority and will be selected automatically to power up the LCD module and the backlight; in cases where there is no VIN available, the VCC pin will power up the whole board. The I2C expander comes pre-configured to work with 5V levels, using the voltage available on the VCC pins, but can also be configured to use 3.3V levels when this voltage is selected in the VI2C jumper on the board - donwload the schematics below for more details).

OLED panels are made from organic materials that emit light when electricity is applied. Different from the LCD which needs backlight, the OLED does not need any backlight to display. Basically, the LCD does not emit light, it only “select ” the right color and intensity from the backlight and thus to display, while for OLED, each pixel of the OLED emits the light by themselves, the customer control all the pixels on/off and the intensity to show the images.