tft lcd vs led lcd free sample

Confused about LED vs. LCD vs. TFT? Here"s everything you need to know. Creating or upgrading a device display or screen can involve a lot of different things, but it often comes down to one major question - what kind of display should you get?

So, there are 3 common displays LED, LCD and TFT available in the market. All terms refer to the flat-panel display, or screen, of a computer monitor or television set. In this article, we are going to differentiate between them. It will help you to choose a better one.

LCD stands for liquid crystal display. Works by adjusting the amount of light blocked. Usually has a backlight but might not (clocks, calculators, Nintendo Gameboy). The green-black ones can be very cheap and are a mature technology. Response time can be slow. An LCD display uses the light balancing qualities of crystals. Today LCDs are used in a great number of products and applications. Your TV, computer screen, calculator, cell phone and the dreaded alarm clock are all made of an LCD flat panel. Color LCDs produce the color based on two techniques: Passive matrix and active matrix. Passive matrix is the cheapest technology of the two. The other technology is called an active matrix or TFT. Active matrix displays produce really sharp and clear images.

This is a type of LCD with a thin film transistor attached to each pixel. All computer LCD screens are TFT since the early 2000s; older ones had slower response times and poorer color. Cost is now very good; power consumption is fairly good but dominated by the backlight. Has to be manufactured out of glass. The TFT layer is embedded in the screen itself, it reduces crosstalk between pixels. Crosstalk happens when a signal sends to a pixel also affects the pixel next to it. This makes the TFT technology the technology offering the best resolution and image quality. It also makes it a bit more expensive. Today TFTs have become the standard when producing LCD screens.

LED stands for a light emitting diode. As the name suggests, emits light rather than blocking it like LCD. Used for red/green/blue/white indicator lights everywhere. Some manufacturers advertise "LED" displays that are TFT screens with a white LED backlight, which is just confusing. Ones that are real LED screens are usually OLED.

Some devices actually have backlights made from Red, Green and Blue LEDs, normally referred to as RGB LED, which tend to have better color reproduction than any other display.

LED screen is just like saying that it is a plastic screen. You still have the WHOLE screen illuminated all the time and LED is "good" only for being more eco-friendly and probably more bright at max setting if you ever need this.

An LCD panel is, in fact, 2 layers of glass with some volume of Liquid Crystal in between. These two form the panel itself. The 2 layers are usually called Color Filter Glass (above) and TFT glass (below).

LCDs can’t completely prevent light from passing through, though, even during dark scenes, so dimming the light source itself aids in creating deeper blacks and more impressive contrast in the picture.

A standard TFT has a whole "lamp" behind it, illuminating the whole screen all the time. This way, you cannot have a true black, as it is still illuminated and stay grayish.

TFTs are a type of active matrix display that controls individual pixel updates several times per second on the screen to update the image relative to the content source.

TFT displays use more electricity than regular LCD screens, so they not only cost more in the first place, but they are also more expensive to operate.

LCDs use fluorescent lights while LEDs use those light emitting diodes. The fluorescent lights in an LCD are always behind the screen. On an LED, the light emitting diodes can be placed either behind the screen or around its edges.

In market, LCD means passive matrix LCDs which increase TN (Twisted Nematic), STN (Super Twisted Nematic), or FSTN (Film Compensated STN) LCD Displays. It is a kind of earliest and lowest cost display technology.

LCD screens are still found in the market of low cost watches, calculators, clocks, utility meters etc. because of its advantages of low cost, fast response time (speed), wide temperature range,  low power consumption, sunlight readable with transflective or reflective polarizers etc.  Most of them are monochrome LCD display and belong to passive-matrix LCDs.

TFT LCDs have capacitors and transistors. These are the two elements that play a key part in ensuring that the TFT display monitor functions by using a very small amount of energy without running out of operation.

Normally, we say TFT LCD panels or TFT screens, we mean they are TN (Twisted Nematic) Type TFT displays or TN panels, or TN screen technology. TFT is active-matrix LCDs, it is a kind of LCD technologies.

TFT has wider viewing angles, better contrast ratio than TN displays. TFT display technologies have been widely used for computer monitors, laptops, medical monitors, industrial monitors, ATM, point of sales etc.

Actually, IPS technology is a kind of TFT display with thin film transistors for individual pixels. But IPS displays have superior high contrast, wide viewing angle, color reproduction, image quality etc. IPS screens have been found in high-end applications, like Apple iPhones, iPads, Samsung mobile phones, more expensive LCD monitors etc.

Both TFT LCD displays and IPS LCD displays are active matrix displays, neither of them can produce color, there is a layer of RGB (red, green, blue) color filter in each LCD pixels to make LCD showing colors. If you use a magnifier to see your monitor, you will see RGB color. With switch on/off and different level of brightness RGB, we can get many colors.

Neither of them can’t release color themselves, they have relied on extra light source in order to display. LED backlights are usually be together with them in the display modules as the light sources. Besides, both TFT screens and IPS screens are transmissive, it will need more power or more expensive than passive matrix LCD screens to be seen under sunlight.  IPS screens transmittance is lower than TFT screens, more power is needed for IPS LCD display.

TFT displays are also known as an “Active Matrix TFT LCD module” and have an array of thin film transistors fabricated on the glass that makes the LCD. There is one of these transistors for each pixel on the LCD.

LCDs use voltage applied to a field of microscopic liquid crystals to change the crystal’s orientation, which in turn changes the polarization of the liquid crystal which creates light or dark pixels on the display.

Beautiful, complex images: All of our TFT modules are full-color graphic displays. Unlike standard monochrome character displays, you can create complex images for an imaginative user experience.

Single Supply: Most of the TFTs use an integrated controller with built-in voltage generation so only a single 3.3v supply is needed for both the panel power and logic voltage.

Many of our character LCD modules use a standard HD44780 controller, so they can be quickly integrated into a new product or used as a replacement in your existing products.

Many of the LCD controllers on board our graphic LCD display modules also include a CGROM (character generator ROM) which allows for easy character information as well as full bit-mapped graphic information to be shown.

Some of the graphic LCD displays have the ability to render graphics in grayscale, enabling you to show images and elements of your UI (user interface) with more depth and definition.

Because OLEDs are emissive, these displays can always be used in dark environments. There is usually a software command or hardware setting that will allow OLEDs to be dimmed.

Some OLED displays are bright enough to be sunlight readable–these models will typically take more current and may have a shorter rated lifetime. Additionally, OLEDs have extremely wide viewing angles.

What makes OLEDs useful for display construction is that they can be fabricated in bulk. Using OLED fabrication techniques, all the diodes can be made at the same time, at a much lower cost. OLEDs also come in a wide variety of colors.

TFT LCD is a mature technology. OLED is a relatively new display technology, being used in more and more applications. As for Micro LED, it is a new generation technology with very promising future. Followings are the pros and cons of each display technology.

TFT Liquid Crystal Display is widely used these days. Since LCD itself doesn"t emit light. TFT LCD relies on white LED backlight to show content. This is an explanation of how TFT LCD works.

Relatively lower contrast：Light needs to pass through LCD glasses, liquid crystal layer, polarizers and color filters. Over 90% is lost. Also, LCD can not display pure black.

Organic Light-Emitting Diode is built from an electro-luminescent layer that contains organic compounds, which emit light in response to an electric current. There are two types of OLED, Passive Matrix OLED (PMOLED) and Active Matrix OLED (AMOLED). These driving methods are similar to LCD"s. PMOLED is controlled sequentially using a matrix addressing scheme, m + n control signals are required to address a m x n display. AMOLED uses a TFT backplane that can switch individual pixels on and off.

Low power consumption and flexible: OLED doesn"t rely on backlight and consumes less power. OLED is essentially created on plastic film. It is bendable and easy to process.

High contrast and vivid color: OLED emits light itself, can produce very bright image with beautiful color. And because OLED can be turned off, it can produce true black.

Stroboscopic effect: most OLED screen uses PWM dimming technology. Some people who are easy perceive stroboscopic frequency may have sore eyes and tears.

​Micro LED, sometimes called μLED is made up of tiny LED, measure less than 100μm. Another way of looking at this is that MicroLEDs are simply traditional LEDs shrunk down and placed into an array.

Replacing organic material with inorganic GaN material eliminates the need of polarizing and encapsulation layer, found in OLED. Micro LED is smaller and thinner, consumes less power.

For years, TFT displays have been the dominating technology in visualization. TFT LCD displays are everywhere in our daily lives; in consumer electronics, health care, communication devices and industry applications. While there are many LCD products in the market, they are not always suitable for every application. This is especially true for industrial TFT LCD. Understanding different requirements between industrial display and consumer TFT LCD, will help determine the best TFT LCD for your application.

Consumer grade TFT LCD like cell phone screen and computer monitor occupy big chunk of LCD market. Due to the nature of consumer market, competitive pricing and quick production cycles, these TFT LCDs are lack of the durability that industrial LCD has. Not like our cell phone screen and computer monitor, industrial LCD displays are used in much challenging environments. For example, an TFT LCD display on production line will face constant vibration, high working temperature. Its endurance to outside condition is a must.

Industrial TFT LCD has very good visibility. Which includes wide viewing angle, so that staff on production line can easily read information from different angles.

Sunlight readable is another important aspect that industrial TFT LCD persists. Many industrial applications are used outdoor, under direct sunlight. And user needs to be able to read what is on LCD screen easily. Topway has years experience on producing sunlight readable TFT LCD by using high brightness LED backlight and low reflectance technologies.

Industrial TFT LCD is made with high quality industrial grade components and material. Only then we could produce high quality TFT display that survives rigid tests like ESD, EMI and aging test, etc. All LCD product from Topway went through strict testings before reaching customers" warehouses.

Industrial TFT LCD has way longer supply commitment than consumer LCD. Ever try to fix a 2~3 years old cell phone"s crack screen? It is very difficult and expensive. Because replacement LCD screen is no longer being made. On the other hand, industrial LCD screen usually is in production for 10 plus years. And most of the time, for Topway anyway, there will be an upgrade model to replace end-of-life product. Thus, our customers won"t need to do much change on their product.

Industrial TFT LCD is a lot better in many areas than consumer one, even they look similar in normal situation. Topway as an industrial TFT LCD manufacturer, has been designing and producing industry grade LCD for more than twenty years. Our commitment on quality and customer service wins Topway friendship and orders. Please feel free to leave us message on your next industry project.

A thin-film-transistor liquid-crystal display (TFT LCD) is a variant of a liquid-crystal display that uses thin-film-transistor technologyactive matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven (i.e. with segments directly connected to electronics outside the LCD) LCDs with a few segments.

In February 1957, John Wallmark of RCA filed a patent for a thin film MOSFET. Paul K. Weimer, also of RCA implemented Wallmark"s ideas and developed the thin-film transistor (TFT) in 1962, a type of MOSFET distinct from the standard bulk MOSFET. It was made with thin films of cadmium selenide and cadmium sulfide. The idea of a TFT-based liquid-crystal display (LCD) was conceived by Bernard Lechner of RCA Laboratories in 1968. In 1971, Lechner, F. J. Marlowe, E. O. Nester and J. Tults demonstrated a 2-by-18 matrix display driven by a hybrid circuit using the dynamic scattering mode of LCDs.T. Peter Brody, J. A. Asars and G. D. Dixon at Westinghouse Research Laboratories developed a CdSe (cadmium selenide) TFT, which they used to demonstrate the first CdSe thin-film-transistor liquid-crystal display (TFT LCD).active-matrix liquid-crystal display (AM LCD) using CdSe TFTs in 1974, and then Brody coined the term "active matrix" in 1975.high-resolution and high-quality electronic visual display devices use TFT-based active matrix displays.

The circuit layout process of a TFT-LCD is very similar to that of semiconductor products. However, rather than fabricating the transistors from silicon, that is formed into a crystalline silicon wafer, they are made from a thin film of amorphous silicon that is deposited on a glass panel. The silicon layer for TFT-LCDs is typically deposited using the PECVD process.

Polycrystalline silicon is sometimes used in displays requiring higher TFT performance. Examples include small high-resolution displays such as those found in projectors or viewfinders. Amorphous silicon-based TFTs are by far the most common, due to their lower production cost, whereas polycrystalline silicon TFTs are more costly and much more difficult to produce.

The twisted nematic display is one of the oldest and frequently cheapest kind of LCD display technologies available. TN displays benefit from fast pixel response times and less smearing than other LCD display technology, but suffer from poor color reproduction and limited viewing angles, especially in the vertical direction. Colors will shift, potentially to the point of completely inverting, when viewed at an angle that is not perpendicular to the display. Modern, high end consumer products have developed methods to overcome the technology"s shortcomings, such as RTC (Response Time Compensation / Overdrive) technologies. Modern TN displays can look significantly better than older TN displays from decades earlier, but overall TN has inferior viewing angles and poor color in comparison to other technology.

Most TN panels can represent colors using only six bits per RGB channel, or 18 bit in total, and are unable to display the 16.7 million color shades (24-bit truecolor) that are available using 24-bit color. Instead, these panels display interpolated 24-bit color using a dithering method that combines adjacent pixels to simulate the desired shade. They can also use a form of temporal dithering called Frame Rate Control (FRC), which cycles between different shades with each new frame to simulate an intermediate shade. Such 18 bit panels with dithering are sometimes advertised as having "16.2 million colors". These color simulation methods are noticeable to many people and highly bothersome to some.gamut (often referred to as a percentage of the NTSC 1953 color gamut) are also due to backlighting technology. It is not uncommon for older displays to range from 10% to 26% of the NTSC color gamut, whereas other kind of displays, utilizing more complicated CCFL or LED phosphor formulations or RGB LED backlights, may extend past 100% of the NTSC color gamut, a difference quite perceivable by the human eye.

The transmittance of a pixel of an LCD panel typically does not change linearly with the applied voltage,sRGB standard for computer monitors requires a specific nonlinear dependence of the amount of emitted light as a function of the RGB value.

Less expensive PVA panels often use dithering and FRC, whereas super-PVA (S-PVA) panels all use at least 8 bits per color component and do not use color simulation methods.BRAVIA LCD TVs offer 10-bit and xvYCC color support, for example, the Bravia X4500 series. S-PVA also offers fast response times using modern RTC technologies.

When the field is on, the liquid crystal molecules start to tilt towards the center of the sub-pixels because of the electric field; as a result, a continuous pinwheel alignment (CPA) is formed; the azimuthal angle rotates 360 degrees continuously resulting in an excellent viewing angle. The ASV mode is also called CPA mode.

TFT dual-transistor pixel or cell technology is a reflective-display technology for use in very-low-power-consumption applications such as electronic shelf labels (ESL), digital watches, or metering. DTP involves adding a secondary transistor gate in the single TFT cell to maintain the display of a pixel during a period of 1s without loss of image or without degrading the TFT transistors over time. By slowing the refresh rate of the standard frequency from 60 Hz to 1 Hz, DTP claims to increase the power efficiency by multiple orders of magnitude.

Due to the very high cost of building TFT factories, there are few major OEM panel vendors for large display panels. The glass panel suppliers are as follows:

External consumer display devices like a TFT LCD feature one or more analog VGA, DVI, HDMI, or DisplayPort interface, with many featuring a selection of these interfaces. Inside external display devices there is a controller board that will convert the video signal using color mapping and image scaling usually employing the discrete cosine transform (DCT) in order to convert any video source like CVBS, VGA, DVI, HDMI, etc. into digital RGB at the native resolution of the display panel. In a laptop the graphics chip will directly produce a signal suitable for connection to the built-in TFT display. A control mechanism for the backlight is usually included on the same controller board.

The low level interface of STN, DSTN, or TFT display panels use either single ended TTL 5 V signal for older displays or TTL 3.3 V for slightly newer displays that transmits the pixel clock, horizontal sync, vertical sync, digital red, digital green, digital blue in parallel. Some models (for example the AT070TN92) also feature input/display enable, horizontal scan direction and vertical scan direction signals.

New and large (>15") TFT displays often use LVDS signaling that transmits the same contents as the parallel interface (Hsync, Vsync, RGB) but will put control and RGB bits into a number of serial transmission lines synchronized to a clock whose rate is equal to the pixel rate. LVDS transmits seven bits per clock per data line, with six bits being data and one bit used to signal if the other six bits need to be inverted in order to maintain DC balance. Low-cost TFT displays often have three data lines and therefore only directly support 18 bits per pixel. Upscale displays have four or five data lines to support 24 bits per pixel (truecolor) or 30 bits per pixel respectively. Panel manufacturers are slowly replacing LVDS with Internal DisplayPort and Embedded DisplayPort, which allow sixfold reduction of the number of differential pairs.

Backlight intensity is usually controlled by varying a few volts DC, or generating a PWM signal, or adjusting a potentiometer or simply fixed. This in turn controls a high-voltage (1.3 kV) DC-AC inverter or a matrix of LEDs. The method to control the intensity of LED is to pulse them with PWM which can be source of harmonic flicker.

Kawamoto, H. (2012). "The Inventors of TFT Active-Matrix LCD Receive the 2011 IEEE Nishizawa Medal". Journal of Display Technology. 8 (1): 3–4. Bibcode:2012JDisT...8....3K. doi:10.1109/JDT.2011.2177740. ISSN 1551-319X.

K. H. Lee; H. Y. Kim; K. H. Park; S. J. Jang; I. C. Park & J. Y. Lee (June 2006). "A Novel Outdoor Readability of Portable TFT-LCD with AFFS Technology". SID Symposium Digest of Technical Papers. AIP. 37 (1): 1079–82. doi:10.1889/1.2433159. S2CID 129569963.

Focus Displays offers a wide range of standard full color TFT displays. 64 million unique colors, high brightness, sharp contrast, -30C operating temperature, and fast response time are all good descriptions of a TFT display. This is why TFT technology is one of the most popular choices for a new product.

Thin Film Transistor (TFT) display technology can be seen in products such as laptop computers, cell phones, tablets, digital cameras, and many other products that require color. TFT’s are active matrix displays which offers exceptional viewing experiences especially when compared to other passive matrix technologies. The clarity on TFT displays is outstanding; and they possess a longer half-life than some types of OLEDs and range in sizes from less than an inch to over 15 inches.

CCFL’s are still available, but are becoming a legacy (obsolete) component. TFT displays equipped with a CCFL require higher MOQs (Minimum Order Quantities) than displays with LED backlights.

Red, Green and Blue (RGB) backlights are built with either a single LED that produces red, green and blue colors or with three separate Red, Green or Blue LEDs.

Backlight brightness (Luminance) is measured in nits. A nit being the amount of light that one candle delivers in a 1 square meter box. The intensity of the LED backlight can be critical when operating in low light or in direct sun light and is usually controlled by adjusting the DC voltage. In many applications this is accomplished through pulse-width modulation (PWM)

The majority of TFT displays contain a touch panel, or touch screen. The touch panel is a touch-sensitive transparent overlay mounted on the front of the display glass. Allowing for interaction between the user and the LCD display.

Some touch panels require an independent driver IC; which can be included in the TFT display module or placed on the customer’s Printed Circuit Board (PCB). Touch screens make use of coordinate systems to locate where the user touched the screen.

Resistive touch panels are the lowest cost option and are standard equipment on many TFT modules. They are more common on smaller TFT displays, but can still be incorporated on larger modules.

Contrast ratio, or static contrast ratio, is one way to measure the sharpness of the TFT LCD display. This ratio is the difference between the darkest black and the brightest white the display is able to produce. The higher the number on the left, the sharper the image. A typical contrast ratio for TFT may be 300:1. This number ratio means that the white is 300 times brighter than the black.

TFT LCD displays are measured in inches; this is the measurement of the diagonal distance across the glass. Common TFT sizes include: 1.77”, 2.4”, 2.8”, 3”, 4.3”, 5”, 5.7”, 5.8”, 7”, 10.2”, 12.1 and 15”.

TFT resolution is the number of dots or pixels the display contains. It is measured by the number of dots along the horizontal (X axis) and the dots along the vertical (Y axis).

Certain combinations of width and height are standardized and typically given a name and a letter representation that is descriptive of its dimensions. Popular names given to the TFT LCD displays resolution include:

Transmissive displays must have the backlight on at all times to read the display, but are not the best option in direct sunlight unless the backlight is 750 Nits or higher. A majority of TFT displays are Transmissive, but they will require more power to operate with a brighter backlight.

A primary job of the driver is to refresh each pixel. In passive TFT displays, the pixel is refreshed and then allowed to slowly fade (aka decay) until refreshed again. The higher the refresh frequency, the sharper the displays contrast.

The TFT display (minus touch screen/backlight) alone will contain one controller/driver combination. These are built into the display so the design engineer does not need to locate the correct hardware.

If you do not see a Thin Film Transistor (TFT) Display module that meets your specifications, or you need a replacement TFT, we can build a custom TFT displays to meet your requirements. Custom TFTs require a one-time tooling fee and may require higher MOQs.

Ready to order samples for your TFT design? Contact one of our US-based technical support people today concerning your design requirements. Note: We can provide smaller quantities for samples and prototyping.

Click calculate to find the energy consumption of a 22 inch LED-backlit LCD display using 30 Watts for 5 hours a day @ $0.10 per kWh. Check the table below and modify the calculator fields if needed to fit your display.

LED & LCD screens use the same TFT LCD (thin film transistor liquid crystal display) technology for displaying images on the screen, when a product mentions LED it is referring to the backlighting. Older LCD monitors used CCFL (cold cathode fluorescent) backlighting which is generally 20-30% less power efficient compared to LED-backlit LCD displays.

The issue in accurately calculating the energy consumption of your tv or computer display comes down to the build quality of the screen, energy saving features which are enabled and your usage patterns. The only method to accurately calculate the energy usage of a specific model is to use a special device known as an electricity usage monitor or a power meter. This device plugs into a power socket and then your device is plugged into it, electricity use can then be accurately monitored. If you are serious about precisely calculating your energy use, this product is inexpensive and will help you determine your exact electricity costs per each device.

In general we recommend LED displays because they offer the best power savings and are becoming more cheaper. Choose a display size which you are comfortable with and make sure to properly calibrate your display to reduce power use. Enable energy saving features, lower brightness and make sure the monitor goes into sleep mode after 5 or 10 minutes of inactivity. Some research studies also suggest that setting your system themes to a darker color may help reduce energy cost, as less energy is used to light the screen. Also keep in mind that most display will draw 0.1 to 3 watts of power even if they are turned off or in sleep mode, unplugging the screen if you are away for extended periods of time may also help.

In this Arduino touch screen tutorial we will learn how to use TFT LCD Touch Screen with Arduino. You can watch the following video or read the written tutorial below.

The next example is controlling an RGB LED using these three RGB sliders. For example if we start to slide the blue slider, the LED will light up in blue and increase the light as we would go to the maximum value. So the sliders can move from 0 to 255 and with their combination we can set any color to the RGB LED,  but just keep in mind that the LED cannot represent the colors that much accurate.

As an example I am using a 3.2” TFT Touch Screen in a combination with a TFT LCD Arduino Mega Shield. We need a shield because the TFT Touch screen works at 3.3V and the Arduino Mega outputs are 5 V. For the first example I have the HC-SR04 ultrasonic sensor, then for the second example an RGB LED with three resistors and a push button for the game example. Also I had to make a custom made pin header like this, by soldering pin headers and bend on of them so I could insert them in between the Arduino Board and the TFT Shield.

Here’s the circuit schematic. We will use the GND pin, the digital pins from 8 to 13, as well as the pin number 14. As the 5V pins are already used by the TFT Screen I will use the pin number 13 as VCC, by setting it right away high in the setup section of code.

I will use the UTFT and URTouch libraries made by Henning Karlsen. Here I would like to say thanks to him for the incredible work he has done. The libraries enable really easy use of the TFT Screens, and they work with many different TFT screens sizes, shields and controllers. You can download these libraries from his website, RinkyDinkElectronics.com and also find a lot of demo examples and detailed documentation of how to use them.

After we include the libraries we need to create UTFT and URTouch objects. The parameters of these objects depends on the model of the TFT Screen and Shield and these details can be also found in the documentation of the libraries.

Next we need to define the fonts that are coming with the libraries and also define some variables needed for the program. In the setup section we need to initiate the screen and the touch, define the pin modes for the connected sensor, the led and the button, and initially call the drawHomeSreen() custom function, which will draw the home screen of the program.

So now I will explain how we can make the home screen of the program. With the setBackColor() function we need to set the background color of the text, black one in our case. Then we need to set the color to white, set the big font and using the print() function, we will print the string “Arduino TFT Tutorial” at the center of the screen and 10 pixels  down the Y – Axis of the screen. Next we will set the color to red and draw the red line below the text. After that we need to set the color back to white, and print the two other strings, “by HowToMechatronics.com” using the small font and “Select Example” using the big font.

drawDistanceSensor(); // It is called only once, because in the next iteration of the loop, this above if statement will be false so this funtion won"t be called. This function will draw the graphics of the first example.

getDistance(); // Gets distance from the sensor and this function is repeatedly called while we are at the first example in order to print the lasest results from the distance sensor

So the drawDistanceSensor() custom function needs to be called only once when the button is pressed in order to draw all the graphics of this example in similar way as we described for the home screen. However, the getDistance() custom function needs to be called repeatedly in order to print the latest results of the distance measured by the sensor.

Ok next is the RGB LED Control example. If we press the second button, the drawLedControl() custom function will be called only once for drawing the graphic of that example and the setLedColor() custom function will be repeatedly called. In this function we use the touch screen to set the values of the 3 sliders from 0 to 255. With the if statements we confine the area of each slider and get the X value of the slider. So the values of the X coordinate of each slider are from 38 to 310 pixels and we need to map these values into values from 0 to 255 which will be used as a PWM signal for lighting up the LED. If you need more details how the RGB LED works you can check my particular tutorialfor that. The rest of the code in this custom function is for drawing the sliders. Back in the loop section we only have the back button which also turns off the LED when pressed.

drawDistanceSensor(); // It is called only once, because in the next iteration of the loop, this above if statement will be false so this funtion won"t be called. This function will draw the graphics of the first example.

getDistance(); // Gets distance from the sensor and this function is repeatedly called while we are at the first example in order to print the lasest results from the distance sensor

Established in 2010, Topfoison has devoted itself to the manufacturing and development of high-quality products for the Wearable device, Smart Watch, VR, Medical device, Industrial LCD display including Color LCD modules/OLED/LCD display/Round lcd screen/Round AMOLED/ Square transflective lcd screen/ IPS full wide display/ 1080p fhd AMOLED and 2K 1440p lcd. Topfoison focus on1.22-7.0 inch small size displays, all the products produced in our company enjoys the most advanced production craft and technology as well as the strictly ISO quality management system.

Established in 2010, Topfoison has devoted itself to the manufacturing and development of high-quality products for the Wearable device, Smart Watch, VR, Medical device, Industrial LCD display including Color LCD modules/OLED/LCD display/Round lcd screen/Round AMOLED/ Square transflective lcd screen/ IPS full wide display/ 1080p fhd AMOLED and 2K 1440p lcd. Topfoison focus on1.22-7.0 inch small size displays, all the products produced in our company enjoys the most advanced production craft and technology as well as the strictly ISO quality management system.