wireless lcd display free sample

This is the era of wireless communication/technology. We can see the rise in number of devices that are using Bluetooth and WiFi these days. With the IoT revolution in the electronics industry as well as the ever increasing devices that needed the internet connectivity we had to shift to IPv6 from IPv4.

With these technological advances we are forgetting about some simpler and older radio frequency devices and schemes. More and more people are publishing sophisticated projects which use IoT, Lora-WAN and stuff even when it is not required in that project. A small project doesn"t need such powerful wireless technology. It is a waste of resources.

Let"s learn more about ASK. As I have mentioned earlier that ASK is a digital modulation technique, means it can be used to transmit digital data wirelessly over a carrier of 433 MHz. The carrier is a sine wave of 433MHz which is switched on or off depending upon the digital bit that is to be transmitted. In this way by switching the carrier on and off one can transmit 0 or 1 respectively.

Circuit diagram of the wireless LCD display via Bluetooth is shown in Fig. 1. It is built around Arduino Uno board along with a 16×2 alphanumeric LCD (LCD1), Bluetooth module (HC-05) and a preset (VR1).

Arduino IDE is used for programming Arduino board. LCD’s library (#include ) is used, which is already available in the latest IDE’s library. Here, the baud rate or speed of serial communication is set to 9600. For serial communication, inbuilt functions such as serial.begin(), serial.available() and serial.readString() are used.

The PCB layout for the wireless LCD display is shown in Fig. 2 and its components layout in Fig. 3. After connecting the circuit on the PCB, follow the steps given below to test the project:

2. Open Arduino IDE. Select COM port from your computer’s Device Manager. Set baud rate to 9600. Compile and upload the code (LCD.ino) to Arduino board.

3. Connect the 12V power supply to the Arduino board. The LED in HC-05 Bluetooth module will blink continuously. This means Bluetooth module is working fine. The LCD will display ‘Welcome’ message. If not, adjust the preset by varying VR1 till you get clear text on LCD1.

5. Open Bluetooth Terminal and pair it with HC-05 module. You will see ‘Connected’ on the app. Type a message and press Send. The message will get displayed on LCD1.

With Wacom One, you get more than just a creative pen display. You have everything you need to get off to a flying start. Our included Bonus Pack is ready and waiting for you. And conveniently, Wacom One is compatible with your computer, as well as certain Android tablets and phones.

Kami transforms any existing document into canvas for expression or an interactive learning experience. Work collaboratively in real-time and ignite creativity with an array of annotation tools accessible with your Wacom pen display and Wacom pen tablet.

Used to working with pen and paper? Well, there"s a new digital world waiting for you. When working on a pen display, your pen can act as different pencils and brushes in a whole range of colors – bundled software ensures you can easily change color or brush size, all with the same pen. And the fact you can easily edit and update work makes Wacom One the ideal product for budding creatives and keen note takers.

This replacement AC Power Adapter (Regional power plugs included) is an external power supply designed to work with the Wacom One creative pen display and the Wacom One X-Shape Cable.

The Wacom One replacement pen is designed for use Wacom One creative pen display (DTC133). The pen is cordless, battery-free with 4096 levels of pressure and a programmable side-switch to put shortcuts at your fingertips.

Our easy-to-use OMRON Platinum Wireless Bluetooth Upper Arm home blood pressure monitor (BP5450) is powered by OMRON Advanced Accuracy technology, which measures five times more data points for more consistent, precise readings. This OMRON-exclusive technology minimizes the impact your breathing and movements will have on your blood pressure reading results, helping to reduce measurement inconsistencies and errors.

The Platinum Upper Arm monitor features a horizontally designed, dual LCD monitor that fits a side-by-side comparison display, so you can immediately compare your current reading to your last reading, providing you easy access to your measurement data. The large, black, backlit side-by-side comparison display makes your readings easier to see.

Ideally, you will want to track the average of three consecutive blood pressure readings every time you check your blood pressure and share these averages with your physician. Along with Advanced Averaging, which automatically displays the average of up to the last three readings taken within the last 10 minutes, this premium blood pressure monitor also contains the OMRON-exclusive TruRead technology which, when turned on, automatically takes three consecutive readings at intervals you can customize for every measurement, and displays the average.

For some people, their blood pressure may be too high in the morning, often called, “morning high blood pressure” or “morning hypertension.” The unique High Morning Average Indicator will calculate your daily morning average blood pressure, and will alert you with a “HIGH” symbol on the display if your morning weekly average systolic blood pressure measures 130 mmHg or above, and/or your diastolic blood pressure is 80 mmHg or above.

This monitor also features another OMRON-exclusive, an Irregular Heartbeat Symbol that not only alerts you if an irregular heartbeat was detected during your measurement, but also displays the number of irregular heartbeats detected (up to three) during your measurement.

IMPORTANT PAIRING NOTE: Before starting to pair your connected device, be sure your monitor is turned off and that the display is blank (i.e., no numbers present).

-Protective LCD Cover: This sleek, protective BP monitor LCD cover (HEM-CACO-734) is designed to conveniently wrap around the blood pressure monitor to provide protection to the LCD and secure the cuff with the monitor for ease of storage and travel.

Based on an Arm® Cortex®‐M4 core running at 64 MHz (application processor) and an Arm Cortex‐M0+ core at 32 MHz (network processor), STM32WB wireless microcontrollers support Bluetooth LE 5.3 and IEEE 802.15.4 wireless standards such as Zigbee, Thread and Matter.

Based on our ultra-low power STM32L4 microcontrollers, the STM32WB MCU series provides the same digital and analog peripherals suitable for applications requiring an extended battery life and complex functionalities. STM32WBx5 wireless microcontrollers, available in multiple packages and different memory sizes, provide users with enhanced performance and flexibility to address different levels of complexity.

System peripherals The STM32WBx5 line includes a wide variety of communication features including a practical crystal-less USB 2.0 FS interface, audio support, an LCD driver, touch sensing, up to 72 GPIOs, an integrated SMPS to optimize power consumption, and multiple low-power modes to maximize battery life.

This product portfolio of 2.4 GHz wireless STM32 MCUs provides integrated solutions from product definition to the prototyping phase, up to the final platform definition.

In addition to its wireless and ultra-low-power features, STM32WB microcontrollers embed security features which reduce device maintenance needs and ensure end devices are trustable and cannot be cloned.

STM32WB microcontrollers include embedded security hardware functions such as 256-bit AES hardware encryption, PCROP read/write protection, JTAG fuse, and public-key cryptography with an elliptic curve encryption engine. The Firmware Upgrade Services (FUS), PCROP and PKA feature ensure secured wireless stack updates, encryption key management and code protection.

The pack includes the STM32WB55 Nucleo-64 and a USB dongle, both based on the STM32WB microcontroller, to immediately get started while enabling a wide range of wireless applications.

We present the design of a 320x256 RGB LED electronic display board intended to be used as a platform to present information of current and future events in schools or office buildings. The proposed design can display up to eight different images, which may include text and graphics. The rendering of these images is done periodically, with the duration of the period being controlled by the user. The images can be created from slides of a power point presentation or directly from stored photos. Loading of new images to the display board is done wirelessly via WiFi from an Android App running on a portable device such as a tablet or a smartphone. We present experimental results on a completed and fully operational prototype system, which includes the RGB LED display board together with the custom-built microcontroller board as well as the Android App. While the current use-application is as an informative message board in a school set-up, the proposed system can be used in any other indoor application. For outdoor usage, the system would require an additional weather-proof enclosure and fixtures.Metadata Overview

There are generally three main categories of electronic displays. In the first category, simpler and more traditional, one can find the systems that use character LCD displays with two or more rows and 10, 20 or other number of characters per row, such as the 16x2 character LCD [1]. This type of display can typically display static or moving text messages [2]. The second category includes all systems that use graphic LCD displays. Examples in this category include small embedded LCD and touch-screen TFT displays (e.g., 320x240 pixels), digital photo displays, and systems that use LCD monitors as the primary method to display text and images [3]. Finally, in the third category, we can find RGB LED displays. Examples in this category include mostly outdoor scoreboard displays as well as highway and business side billboards. Their complexity and costs are high and depend on the size, which is typically large; see for example the commercial products from Daktronics [4]. However, one can find smaller size examples created by hobbyists, including designs that use just one 64x64 RGB LED matrix panels [5] or just one 32x32 matrix panel [6]. The advantages of RGB LED displays compared to the color LCD displays include better visibility in sunlight conditions, better contrast for crisper details, purer colors, and reduced reflection. However, their power consumption is typically large and their cost relatively high. Finally, while most of these example designs are controlled by microcontrollers, there are solutions that use field programmable gate arrays (FPGAs) as well for improved speeds [7].

The problem of designing and prototyping large RGB LED displays has been less researched in the past literature. That is because this is more a problem of development rather than of theoretical research and because there exists already many commercial offerings of such displays from established companies, some of which were mentioned in the previous paragraph. Nevertheless, one can find prior research studies on power supplies for RGB LED displays or especially on new circuit solutions for LED drivers. For example, the study in [10] proposed a microcontroller-based driver whose objective was to maximize the LED efficiency. They reported a prototype for a 3x3 LED matrix and achieved efficiency greater than 92%. A dimmable multi-channel RGB LED driver was reported and studied with a nine LED string in [11]. Energy savings was the objective of the LED driver studied in [12]. The driver uses a multilevel pulse width modulation (MPWM) driving method combined with simple video signal conversion techniques. It was demonstrated for a 32x32 LED pixels display. The study in [13] addresses the challenges of active image adjustments and processing, considering the non-linearity of the LED display element. They propose a method for the nonlinear adjustment of the images contrast. The advantage of the proposed method is that the images can be displayed on OLED or LED displays with the unified luminance signal, for grayscale images, or with separate RGB controls. Other studies focused on the design of individual LEDs; such an example is the study in [14] that proposed solutions based on dielectric compound parabolic concentrators (CPCs) in order to increase brightness. Such studies are outside the scope of our paper, which focuses on the system integration design aspects, both hardware and software, and prototyping of large RGB LED displays.

In this paper, we present the completely open-source design of a 320x256 RGB LED electronic display board intended to be used a platform to present information of current and future events in schools or office buildings. While the current use-application is as an informative message board in a school set-up, the proposed system can be used in any other indoor or outdoor application (for outdoor usage, the system will need weather-proof casing though). Designed to be cost-effective yet extendable, we hope this design will be adopted and improved in other practical and educational settings.

The integrated 2MB of flash memory of the MCU is used as the primary frame buffer that stores the currently displayed image on the display. It is shown as the “Frame Buffer 2” in Fig. 2. An additional external 2MB parallel SRAM chip is used to store the image to be displayed next. This memory, indicated as “Frame Buffer 1” in Fig. 2, effectively plays the role of a cache between the MCU and the memory system formed by eight different Flash memory chips indicated as “Flash 1..8” in Fig. 2. The eight 2MB flash chips store the current presentation slides or “project”, with one slide per flash chip. The flash chips—physically placed close to the microcontroller to reduce communication delays—were chosen due to their low cost, ease of use, and large number of write cycles (100,000 cycles typically). High performance is achieved by the MCU’s 50MHz External Bus Interface (EBI) feature that is exploited to fetch image data into the primary frame buffer, “Frame Buffer 2”. The WiFi module is the popular and low cost ESP8266 module, which provides its own connection to the device that runs the Android App and thus it does not require a separate Internet service. A new “project” represents eight different images, which are uploaded via the WiFi connection from the App to the eight flash chips.

In addition to driving the display, the microcontroller also has several other tasks to service. During normal operation, up to eight images are stored across eight 256KB serial flash memory chips. This external non-volatile memory acts as long-term image storage, and stores image data across MCU resets and power cycles. It is accessed through a Serial Peripheral Interface (SPI). The MCU can read and write entire images worth of data to a flash chip in about three seconds. When a project is programmed into the system, each image is stored in the SPI flash, while the number of images for the project and the cycle time between images is stored into the microcontroller’s internal flash.

The microcontroller also has an external parallel 256KB SRAM. It is able to read and write data to this SRAM through the External Bus Interface (EBI). EBI allows external memory to be attached to the MCU and it treats it just like any other virtual memory address space. This allows data in EBI SRAM to be treated like a normal byte array in C firmware. During normal operation, while an image is being shown on the screen, the next image to be displayed is moved from SPI Flash into EBI SRAM. When the image is ready to be displayed, it is moved all at once from EBI SRAM into the internal frame buffer and shown on the screen. In this memory structure, EBI SRAM acts as a data cache, since moving data from EBI SRAM into internal RAM is much faster than moving data from SPI Flash into internal RAM. Using this technique, image transitions appear seamless.

A custom Android App, named MU-MatriX (available already for download on Google Play) was developed to allow the user to create and upload to the display system new “projects”. A “project” consists of eight images that form a presentation displayed periodically at a configured interval. The app stores each project’s name, set of images, and duration between image switch into its internal application storage. After naming a new project, a user can populate the project with images, selecting them one-by-one from their device. The images can maintain the aspect ratio of the original image or stretch to fit the size of the display board. There is also the option to rotate images in 90 degree intervals before adding them into the project. In the background, any selected image is saved off into a 320x256 bitmap with black background filling in any gaps created by the aspect ratio lock. As images are being added to a project, they can be reordered by simple up and down arrows next to their thumbnail on the “Edit Project” screen. A spinner widget provides a drop-down selection for the project-level property of duration between slides.

The default display board device is automatically stored under the user’s device list on app installation. The IP address and port number used by default for the ESP8266 WiFi module (on the logic board) are simply placed under a device name “Default Display Board”. The app allows more than just this one display board configuration to be saved in memory, allowing for this system to scale to multiple screens all managed under one app. A device control screen gives the app simple commands to send the Wifi module on the Logic Board: Power On, Power Off, and a screen brightness slider that sends a numeric value between 5 and 100. Simple WiFi messages holding single-line commands are sent over the network using the TCP protocol. Uploading a project to the Logic Board from the application takes a little bit more work and is given its own screen within the app. After selecting one of the projects, one of the hardware devices, and pressing “Upload”, a progress bar and message will become visible on the screen tracking the conversion and transmission of each image within that project. After all the images have been sent, a message will notify the user of the upload completion.

The electronic display system consumes significant power due to the large number of LEDs. The power supply can provide up to 50 A. Thus, users must be cautious of the high currents supplied to the RGB LED panels. In our current prototype, connections are accessible on the back of the panel, so, there is the risk of immediate contact with such connections. We plan to enclose the entire panel inside a wood enclosure with a back lid such that no electrical contacts can be directly accessed (such an enclosure is not part of the current design and is not described in this paper or in the documentation).

The following table lists the metrics or figures of merit that were tested and validated using the complete hardware prototype of the electronic display system as well as the fully operational Android App.

The objective of this experiment was to verify that eight images can be saved to the flash chips located on the logic board and that all images can be displayed correctly in order and repeatedly. The testing strategy was to cycle through all eight flash chips, write and then read the image data from, and drive the LED panels to display each of the images. First, all eight flash chips were written to with eight different images. Then, each image was read from the flash chips and displayed onto the panels. The images displayed on the panels were verified whether they were the desired image. This was repeated five times and all images were changed each repetition to verify the reliability of the entire process of writing and reading images into the flash chips. During this process, we monitored the error (as percentage of pixel data written or read incorrectly) during both writing to and reading from the flash chips. This test was successful with an outcome of 0% error.

The objective for this experiment was to identify the optimal number of bits for the color representation used to render images. The constraints of this experiments included the amount of memory available inside the microcontroller to implement the buffer (stores the data of the image currently being displayed) as well as the time it takes to upload all eight images from the App to the board’s flash chips. The desired color representation was 12-bit color code, which would be capable of generating 4096 different colors per pixel. However, due to how the 5x4 panels (64x64 pixels each) are driven by the only 8 PWM frames (giving 3 bits per color channel) with information about pixels forming an image, we arrived at the compromise of using only a 9-bit color code, which is still capable of generating 512 different colors per pixel. This color code ensures that images have reasonable color resolution to make them appear in natural colors onto the display. While 12-bit color code would obviously be preferable, the 9-bit color code is sufficient to be able to display rich colors, yet to restrict the amount of memory required, achieve better performance (as refresh rate), and to naturally match the PWM control of the 64x64 LED panels.

The objective of this experiment was to verify the Android App and the logic board can communicate successfully via WiFi. The ESP8266 module, mounted on the logic board, was used for this connection. The test plan for this experiment involved sending 20 images of data from the Android App to the logic board and verifying that no data was lost during the transfer. Testing to be sure that no data was lost in the transfer involved displaying the image onto the screen and verifying that the image appeared as intended. This test was successful with an outcome of 0% error.

The objective of this experiment was to verify that the microcontroller was fast enough to properly display the images without any flicker. This was performed by using an oscilloscope to measure the frequency of the clock and latch signals and seeing that the images displayed on the panels did not flicker. This procedure was repeated five times on five different images to verify that a range of different detailed images can be shown without flickering. This test was successful with an achieved refresh rate of 30Hz.

The electronic display is completely reproducible as all the hardware components are readily available from various vendors and the complete design files are made publicly available. Designed to be cost-effective yet extendable, we hope this design will be adopted and improved upon in other practical and educational settings. At the minimum, the display can be replicated as presented and used out of the box. We envision two main ways to extend it. First, the display size could be increased by adding more 64x64 RGB LED panels to the rows and columns. This will potentially require power supplies capable of providing higher currents. Also, the firmware residing on the MCU of the controller board will need to be changed to account for display sizes different than the current 320x256 LEDs. Second, the system could be extended to add the capability of playing video. Such an extension will be more challenging. It could be done by keeping the display continuously connected to the App (or the Internet), which would stream desired videos. Another idea is to modify the controller board in order to include larger capacity flash memory or a micro SD card, which could store large video files. While doable, such changes are major changes to the current design.

We believe that our design has more unique value in educational contexts, because in business contexts, companies can purchase such display boards from established digital display power-houses such as Daktronics. In educational contexts, one can use the proposed design as an open-source flexible “workbench” for various studies in courses on embedded systems, digital signal processing and design, or wireless communications. For instance, in a typical embedded systems course, examples of such studies may include: 1) Investigation of the power consumption and of firmware techniques to reduce it, 2) Laboratory experiments where students are required to implement essential modules of the firmware. Examples of such modules can cover: the WiFi communication between the design and the mobile app, the module responsible for debugging features via the UART peripheral of the microcontroller, etc. The existing design could serve as a platform to verify software development tasks covering microcontroller firmware and mobile app development as well.

The bill of materials for the electronic display system is listed in Table 2. Detailed specifics on each of the electronic components (i.e., resistors, capacitors, etc.) are not included here for brevity (the list is too long); however, they are available in the online repository.

Complete design files, both hardware and software, and documentation are made publicly available in the online repository. In the simplest scenario, one can simply duplicate the proposed electronic display system. The most challenging aspect in this process would be the soldering of all the SMD components on the logic board, because it requires prior experience and SMD soldering skills as well as the availability of a reflow oven. Otherwise, everything is rather simple and straightforward to assemble and to program. Extensive efforts were put into implementing a comprehensive help and debugging capability for the logic board. To use this capability, one would only need to connect a serial terminal (such as Putty) to the USB port of the logic board, then, follow the prompts. More detailed information on this debug ability is provided in the documentation for the firmware.

Perhaps the most notable aspect regarding the technical implementation of this design is that it provided an excellent educational value for the duration of two semesters. More specifically, 1) it required us to develop our own method of “packetizing” the pixel data of all eight images transmitted from the mobile app to the display board via WiFi and 2) it provided a context where hardware and firmware designers needed to team-up with mobile app software developers and create a product that works reliably and  repeatedly. This required good communication skills and collaboration to develop common testing strategies.

The entire design is made open source and publicly available. The following repository contains both hardware and software design files. Additional information, including a project poster and a short video presentation is available at (project “RGB LED Electronic Display”): http://dejazzer.com/hardware.html (archived version)

We presented a completely open source design of a 320x256 RGB LED electronic display board created from a 5x4 array of 64x64 pixels RGB off-the-shelf panels. The electronic display is intended to be used as a display board of information of current and future events in schools or office buildings. The information is presented under the form of eight images or slides that are displayed periodically by the board. The images can be uploaded to the board system via WiFi from an Android App that was custom developed for this purpose. A complete prototype was built and tested successfully. Despite its relatively high overall cost, the proposed electronic display system is extremely easy to use. The complete design files, both hardware and software, are made publicly available. As such, we hope that this design can serve as a starting point for other researchers and educators who are interested in developing more complex RGB LED electronic displays.

As discussed in the Section “Reuse potential and adaptability” above, the proposed electronic display could be extended in several ways. Currently, we are planning to extend the design in order to be able to play video as well.

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M. Andrei, S. Moldovanu, and N. Nistor, "Nonlinear transformations applied to image processing on the RGB LED display," Int. Symposium for Design and Technology in Electronic Packaging​ (SIITME), 2018.

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