The problem stems from the Arduino's Serial to USB converter chip, the FTDI FT232R. The FTDI can't send a USB packet to the computer for every byte that comes from the Arduino's microcontroller Also, Arduino UNO is attached with two LEDs and one Servo Motor. So the slave Arduino is controlled from the Master Modbus Software. The communication between the Arduino UNO and the Modbus Master Software is accomplished by using the RS-485 module. For connecting it with PC, the USB to RS-485 converter module is used Hardware requirements. An Arduino(I used an Arduino UNO, but most Arduinos should work for this) The serial component you want to communicate with through USB.(I used a TinySine Serial Bluetooth Module 4.0 BLE w/ iBeacon support void setup() { pinMode(13, OUTPUT); } void loop() { digitalWrite(13, HIGH); delay(1000); digitalWrite(13, LOW); delay(1000); } This is a simple sketch which is used to blink the inbuilt LED once a second.
If the USB Device was a keyboard, it only needs to know the basic USB protocol and the HID USB protocol. In order to offer up a USB port the Arduino Nano uses an FTDI chip FT232RL. This chip supports a Serial Port USB Device. It does not appear to support HID USB Devices First check with dmesg | grep tty if system recognize your adapter. Then try to run minicom with sudo minicom -s, go to Serial port setup and change the first line to /dev/ttyUSB0. Don't forget to save config as default with Save setup as dfl. It works for me on Ubuntu 11.04 on VirtualBox. improve this answer. edited Nov 27 '15 at 12:04 I want to use the hardware serial port (pin 0 RX and 1 TX) to connect a MAX485 IC. Internally these pins are also connected to the onboard USB to serial converter microcontroller which is used to flash the ATMega328 using the bootstrap code In this tutorial, we will explore the use of Serial Communication in Arduino Uno. Arduino has built-in support for UART which enable serial communication. UART as a serial protocol is most useful and famous protocol. The Arduino can transmit and receive data to the PC over USB Cable. This comes handy when we want to send the sensor data from.
Windows 10 serial USB problems The latest (January) update to Windows 10 seems to cause problems with the USB serial driver when connecting to an Arduino. I can upload a small sketch to an Arduino Mega, but larger sketches fail with an averdude checksum error, and I get periodic freezes when sending commands via USB serial to my 3D printer Arduino Stack Exchange is a question and answer site for developers of open-source hardware and software that is compatible with Arduino. It only takes a minute to sign up. Don't connect these pins directly to an RS232 serial port; they operate at +/- 12V and can damage your Arduino board. To use these extra serial ports to communicate with your personal computer, you will need an additional USB-to-serial adaptor, as they are not connected to the Mega's USB-to-serial adaptor On the USB to TTL Serial Cable this wire is usually white (color may be vary). The Circuit The circuit in this article demonstrates how to connect a Maxim DS18B20 temperature sensor (that utilizes the Dallas OneWire protocol) to the ATtiny85 and send the results over the serial port to the Arduino IDE
Flash Program ESP-01 using USB Serial Adapter. Programming ESP is a bit hard for beginners. In this tutorial, we will make it easy for you to understand the initial step so you can do it your self Good programmer for Arduino Pro Mini, 3V and 5V selection, using USB Mini (not Micro) port. good serial driver, pins marked clearly, can do 5v or 3v vcc on output. I use to program Arduino Pro Mini, which lines up perfect with the 6 programming pins FT232RL USB to TTL Serial Interface Adapter Test Program /* * FT232RL USB to TTL Test Software * This just turns a Arduino into a slave device that will receive characters over * a serial interface and echo them back to the sending device as well as print it to * the Serial Monitor Window
RootSaid a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites. As an Amazon Associate we earn from qualifying purchases. * Arduino Serial Bypass - use an Arduino as a dumb USB 2 Serial Converter * * This code makes the Arduino not interfere with pins 0 and 1 * which are connected to RX and TX on the FTDI chip. This allows * the data coming from the FTDI USB 2 Serial chip to flow directly * to another device. Since RX and TX are labeled from the Arduino's USB is divided into 2 types. USB Hosts and USB Devices. We are not concerned about USB Hosts here. USB Devices only need to know about their own functions / features. If they are a serial port device, like the FTDI chip on the Arduino Nano, they only need to "speak" basic USB protocol and the serial CDC USB protocol. If the USB Device was a keyboard, it only needs to know the basic USB protocol and the HID USB protocol. This driver comes with the Arduino IDE, in the root folder you can find a folder named drivers. The USB Serial Adapter has an onboard mini-USB connector and 5 pins including RX (for receiving data from the computer) and TX (for transmitting data). 5V or 3.3V(selcted by switching the jumper), Ground and a Reset pin are also exposed
Disclosure: Bear in mind that some of the links in this post are affiliate links and if you go through them to make a purchase I will earn a commission. Keep in mind that I link these companies and their products because of their quality and not because of the commission I receive from your purchases. The decision is yours, and whether or not you decide to buy something is completely up to you. Compare Pricing, Inventory and Datasheets for Millions of In-Stock Parts This is a compact circuit that will help us to translate the communication between PC and the microcontroller IC. The USB to RS232 chipset based TTL provides you an easy and convenient way to connect your RS232 TTL Devices such as Arduino boards to your PC via the USB port. usb-serial-for-android. This is a driver library for communication with Arduinos and other USB serial hardware on Android, using the Android USB Host Mode (OTG) available since Android 3.1 and working reliably since Android 4.2. No root access, ADK, or special kernel drivers are required; all drivers are implemented in Java
This is the chip that helps you upload your program to the microcontroller. Once the code is uploaded, this chip will help the Arduino board to send messages back and forth between the Arduino and the PC. The adapter can be plugged into Arduino Pro Mini port. PL-2303HX USB serial adapter used to program Arduino Pro Mini. Now, unless you're using Windows XP or Linux, you'll have a surprise when you'll attempt to use PL-2303HX on Windows 7, 8 or 10. The bad thing is that I still found some USB serial cables with this chip version in local stores
Most new users find it difficult to get the USB drivers. Because Arduino Uno Clone does not use the same driver chip with Arduino Uno R3 Original. But don't worry, Srishti Robotics have provided two drivers. Use the USB / Serial CH340 / CH341 Driver's Download: Windows 32 bit : Download. Windows 64 bit : Download. Linux : Download The code is written in type of C/C++ and when you click on the upload button, the code is compiled and converted to hex format. It is this hex file that is uploaded to the microcontroller IC. To fix the Raspberry Pi and Arduino, you can use the SunFounder RAB Holder. Just use a USB cable to connect the two. Then type in lsusb in the Raspberry Pi terminal, and you can see the device has been connected: Arduino SA Uno R3; for other boards using FTDI, it should be Future Technology Devices International, Ltd FT 232 USB-Serial (UART) IC Arduino and Python-based project that will help us read the sensor values and plot it on Python. Arduino Real-Time Plotting with Python. by Asim Zulfiqar and High Voltages. I made a tool to program the Arduino Pro Mini without the need to solder pins to attach the USB bus port. Programming the Arduino Pro Mini without Soldering Pins FTDI also makes other parts that aren't USB to serial, but their USB to serial chips are quite ubiquitous and are used on many development boards, including the Arduino board. FTDI provides the chip and the associated driver, making it very convenient to add USB support to a device that uses a standard serial port in a world where serial ports.
USB to Serial 3.3V Regulation Buffer for RX LED GND GND CH340G GND 10pF 10pF 12MHz microB GND GND AP2112-3.3V 1.0uF 1.0uF GND GND 5V 5V 10nF GND 3.3V 1K 0.1uF VCC 5V 3.3V GND VCC VCC 330 VCC GND VCC Default 3.3V Move jumper to 5V for 5V VCC and Logic Serial Connection U2 GND 1 TXD 2 RXD 3 V3 4 UD+ 5 UD-6 XI 7 XO 8 CTS 9 DSR 10 RI 11 DCD 12 DTR. For example the Arduino Mega has different Serials (Serial, Serial1, Serial2, Serial3) and the Arduino Zero has a native USB port only (use SerialUSB instead of Serial). On the Raspberry Pi, you can connect many Serial devices on the USB ports
Unable to connect using required security protocol. To access the page requested, please upgrade or use a different browser or mobile device to ensure that your experience on Amazon will be uninterrupted. To discover this feature, we will create a custom USB sensor, and forward all events to the Android Things board over USB. You can see below a video of what we will achieve: the USB device will be an Arduino NFC reader. When scanning a tag (or an amiibo), the Arduino will forward NFC data to the Android Things board over USB
SerialPort^ arduino; arduino = gcnew SerialPort(portName, baudRate); Opening The Port. Just like with text files the first thing you have do is open ports. Open is a method of the serial port class of which arduino is an object of. arduino->Open(); The Loop. We will use a do while loop to run the loop the first time our program is run Most new users find it difficult to get the USB drivers. Because Arduino Uno Clone does not use the same driver chip with Arduino Uno R3 Original. But don't worry, Srishti Robotics have provided two drivers. Use the USB / Serial CH340 / CH341 Driver's Download: USB Serial Driver CH 340 can be used for Windows XP / Win 7 / Wind 8 The FTDI FT232RL is a USB to serial UART interface with optional clock generator output. It's the essential tools for establishing communication between PC and MCU. The best tool for board interfacing with a basic Arduino without it's own USB interface like Sniffer Nano, Colorduino, etc. * Xbee module not included. Features. Reset button for.
Of course, the baud rate of the device and the computer must match. You can then use Putty or Arduino's Serial Monitor to see the data being sent by the device or to send data to the device. You cannot use the same serial port in your app that is being used by the protocol, e.g. You cannot use Serial (Serial0) when the library uses NeoSerial, etc. You can modify this lib easily to use other hardware serial ports on bigger boards than the Arduino Uno if you want to free up your USB Serial connection A year ago I tried the trick to use the Arduino Uno as an USB to serial converter by removing the ATMEGA328 chip from it’s socket and later also by connecting RESET to GND constantly. Both worked fine! But I’ve never thought of just setting digital pin 0 and 1 as inputs so they don’t interfer with the communication. What an Brilliant idea! Adafruit Industries, Unique & fun DIY electronics and kits FTDI Friend + extras [v1.0] ID: 284 - Note: These use genuine FTDI chips, either we purchase them or they are manufactured to our specifications with the requirement of genuine FTDI chips 10/22/14 - read more.Long gone are the days of parallel ports and serial ports. Now the USB port reigns supreme
Usb TO SERIAL CONVERTER. Shop Now Usb To Serial Converte So I searched for the solution and I got arduino can be used as usb to serial converter. I connected the air module to Arduino UNO as mentioned below Module 5v to arduino 5v Module GND to Arduino GND Module Tx to Arduino Tx Module Rx to Arduino Rx and Reset and GND in arduino are connected Find many great new & used options and get the best deals for FT232RL 3.3V 5.5V FTDI USB to TTL Serial Adapter Module for Arduino Mini Port at the best online prices at eBay! Free shipping for many products
thank you so much for posting this!!! i needed an ftdi chip to program my steering wheel module from axxess and was too cheap to buy one and used my arduino to do it instead. worked perfectly! Parallax has designed a USB to Serial (RS-232) adapter that is compact and economical to provide a Virtual Com Port for all of our products that have a DB9 (9-pin) serial connector. Updated FTDI USB drivers for Windows are included in the latest versions of the BASIC Stamp Editor, Propeller Tool, and SX-Key IDE software packages To do that, you don’t need to unplug the Atmel chip from its place. Before using your Arduino board as usb-serial converter you can upload that piece of code.
So with 3rd method (sketch), is it possible to load a sketch on a pre-bootloaded ATMEGA without need to remove the chip from Arduino, all right? Thank you for explain! In this tutorial, we will see how to install the Cp2102 Usb to Serial Drivers. Download the Usb2Serial drivers for this link and follow the below steps to install the Usb-To-Serial drivers. Step1: Connect the USB2Serial breakout/Starter 8051 board to system using the USB cable. Open the device manager, now the device will be listed in other. Once you click on the upload button, the code will be compiled and at that time the status bar on the bottom will be changed to “Compiling”. At that time, press and hold the reset button the Arduino Pro Mini
My idea is to add another USB port so I cant power my device with the new USB port and use free digital pins as input/output of the new USB serial port in V-USB project.You could just program the Arduino with the default “empty” sketch (i.e. empty setup() and loop() functions). Since all digital pins default to input mode after a reset, they will remain as input, since the empty sketch will not change the mode of the pins. Arduino USB-to-Serial Tutorial - Programming the Pro Mini - Duration: 11:04. Julian Ilett 450,816 views. 11:04. 1-Day Project: Build Your Own Arduino Uno for $5 - Duration: 14:23 Almost all the Arduino boards like UNO, nano, MKR series can be programmed by connecting it to the USB port of a PC.
So if the USB To RS232 PL2303 TTL Converter Adapter does not have a DTR pin, we will have to manually reset the Arduino Board in order to upload the code. This will freeze the execution of the currently uploaded code and waits for the USB To RS232 PL2303 TTL Converter Adapter to send the new code.If you are connected to internet, just plug CH340 USB to serial converter to your computer, windows will detect and download driver. You will see following message on successful installation. CH340 is installed on comport 23.The Arduino UNO has its own FTDI chip whose function is to convert TTL signal levels to USB. This is why you can communicate with the board serially using a USB cable and the Serial Monitor feature of the Arduino IDE.
void setup(){ pinMode(0,INPUT); pinMode(1,INPUT); } void loop(){ } I hope it helps someone out there. Arduino, Maker Uno, Raspberry Pi, Raspberry Pi 4, USB Serial Let's try to communicate between Arduino and Raspberry Pi through USB cable using Serial communication. Introductio
This is PL2303 CH340G USB To TTL(Serial) Converter For Arduino Nano Raspberry Pi USB to TTL / USB-TTL /STC microcontroller programmer / PL2303 in nine upgrades plate with a transparent cover Compatible with ARDUINO, RASPBERRY PI, AVR, PIC, 8051, etc The serial to USB(TTL) IC (either FTDI FT232RL or ATmega8U2) is connected to Arduino pins 0 and 1. If we hold the processor in RESET mode, then all its GPIO pins will me in tri-state , effectively removing it from the circuit and you can directly interface the serial to USB IC with your device Installing Drivers for an Arduino Nano in Windows. January 30, 2015 If you are attempting to use an Arduino Nano on a Windows machine and having no luck finding drivers automatically, chances are it is due to a counterfeit FTDI chip which unfortunately does not work with the automatic driver finding functionality in Windows
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Here I attempt to use 3 different USB to Serial modules to program a clone Arduino Pro Mini. The chips are the FTDI FT232RL, the Silicon Labs CP2102 and the Prolific Technologies PL2032HX A mini-USB to 6-pin serial port module used to communicate with Arduino boards and modules. It uses the original FT232 chip with power/sending/receiving indicator and also a selectable 3.3V and 5V power option to suit different boards
Sending simple serial commands to an Arduino is the easiest way to communicate between an Arduino and a computer. The computer could be a PC, a Raspberry Pi, or any device that communicates with serial. By sending and decoding a single character it is easy to add a simple debug menu or even serial menu. Plus, it is easy to extend Here I will show you how you can upload any code to any Arduino board using Arduino IDE and USB to Serial converter. Let us start with the basics. Arduino Behind the Scenes Arduino is a micro controller this statement is technically incorrect. Arduino is a platform/board, which has a micro controller in it. Arduino boards uses a series of. Adafruit Industries, Unique & fun DIY electronics and kits Adafruit CP2104 Friend - USB to Serial Converter ID: 3309 - Long gone are the days of parallel ports and serial ports. Now the USB port reigns supreme! But USB is hard, and you just want to transfer your every-day serial data from a microcontroller to computer. What now? Enter the Adafruit CP2104 Friend!This is a high-quality CP2104.
Here's the connection diagram to connect the PIC (crystal and MCRL pullup omitted) to a computer via an Arduino UNO: 'Serial USB Terminal' is a line-oriented terminal / console app for microcontrollers, arduinos and other devices with a serial / UART interface connected with a USB to serial converter to your android device. This app supports USB to serial converters based on - FTDI FT232, FT2232, - Prolific PL2303 - Silabs CP2102, CP2105, - Qinheng CH340 and devices implementing the USB CDC protocol. Current Arduino boards are programmed via Universal Serial Bus (USB), implemented using USB-to-serial adapter chips such as the FTDI FT232. Some boards, such as later-model Uno boards, substitute the FTDI chip with a separate AVR chip containing USB-to-serial firmware, which is reprogrammable via its own ICSP header Once the code is compiled, the status will be changed to uploading. Now release the reset button and the code will be uploaded in no time. Easy as that!! USB to Serial/TTL Adapter. The first approach involves the connection of a USB to serial adapter to the microcontroller. The USB to Serial/TTL adapter converts data signals from the USB on the computer to serial/TTL for the microcontroller and vice versa. This enables communication from the microcontroller (serial) with the Arduino IDE running.
The Arduino Uno can send data (such as a text message) to the PC over the USB cable. The Arduino IDE has a serial monitor window that can be opened and will receive and display the data sent from the Arduino board. Data can also be sent to the Arduino board from the serial monitor. This serial communication is very useful for controlling. SparkFun Serial Basic Breakout - CH340C and USB-C In stock DEV-15096 This SparkFun Serial Basic Breakout is an easy-to-use USB-to-Serial adapter based on the CH340G and takes advantage of the h Draft saved Draft discarded Sign up or log in Sign up using Google Sign up using Facebook Sign up using Email and Password Submit Post as a guest Name Email Required, but never shown
Since RX and TX are labeled from the Arduino's point of view, don't cross the wires, but plug the device's RX wire into the RX pin 0 and the TX wire into the TX pin 0. This should work with any Arduino compatible boards with a USB to serial chip, but it's nice that it has been confirmed to work on Wemos D1 mini USB-TTL Arduino Tx ----- rxPin Rx ----- txPin Gnd ----- Gnd If all you want to do is to get the data on your PC then you can use any terminal program including Arduino IDE Serial monitor to display the data coming from your spare digital pins. But make sure to display the data on Serial monitor you need to select the com port of the USB-TTL.
this is the output when i boot up the ESP8266. the output goes via the CH340 on the host arduino board to my windows laptop that’s running tera term (or just the arduino serial monitor; either works). Arduino IDE Story If we look at the schematic of Arduino, we will see that the RX and TX pins are connected to the FTDI chip (as we expected) (on Arduino board as pin 0 and pin 1) That means we can use those pins for using the FTDI chip itself If you have any questions about the Arduino USB Serial extension then head on over to the Thunkable Community where you'll find lots of amazing people who are happy to help you out. Blocks Starting a Connection. Transmit and Receive Dat I'm working on a project that needs to use USB to pass serial messages between Arduinos (I can't use I2C or SPI for a few reasons - I especially need USB's support for hot-swapping and address allocation). So far I have the USB Host Shield set up on one Arduino Uno, connected to the standard USB port on another
Arduino Converts Serial To Parallel: The Paralleloslam simple to have an Arduino convert incoming serial data into a parallel output to the printer. USB-parallel converters, like the usb. In this post I will explain everything you need to know about arduino programming, uploading and different logic levels that are involved in the program uploading. Activate the Serial Monitor within the Arduino IDE, clicking on the menu item Tools> Serial Monitor. Fig.10: you can open the serial Monitor from the menu A new window will appear to us, the Monitor Serial precisely and with it you will be able to experiment by writing directly the angles you want the servo motor to be moved AutoReset is a feature, which enables us to upload the compiled sketch to the Microcontroller without pressing the reset switch. The way it works is by sending a reset signal (GND) to the reset pin using the DTR signal on the RS-232 interface.Arduino uses FTDI chips to create serial port connection between computer and the chip, so you can program the Atmel chip inside the Arduino board, without the need of any ISP programmers. If we look at the schematic of Arduino, we will see that the RX and TX pins are connected to the FTDI chip (as we expected) (on Arduino board as pin 0 and pin 1) That means we can use those pins for using the FTDI chip itself.
Plug the board into your computer. Once plugged in, the operating system should recognize it as the appropriate device. In the Arduino IDE, click Tool -> Ports to ensure the device has been recognized. The SparkFun RedBoard will appear a cu.usbserial-XXXXXX device. The Arduino Uno will appear as a cu.usbmodemXXXXXX device The USB Serial Adapter has an onboard micro-USB connector and 5 pins including RX (for receiving data from the computer) and TX (for transmitting data). 5V, Ground and a Reset pin are also exposed. Status lights include power, RX and TX activity. The adapter can easily connect to the Arduino Mini MegunoLink supports serial connections with your Arduino at baud rates from 300 to 500,000 baud. Serial connections are mostly commonly made through the USB connector on most Arduino boards, FTDI adaptor cables or bluetooth modules. To setup a serial connection As mentioned, there are two types of USB To RS232 PL2303 TTL Converter Adapter. The one with DTR and one without DTR pin.There are boards like Arduino Pro Mini and Lilypad that are really small and less costly that doesn’t have the IC that facilitates the communication between the Arduino Board and the USB. So in order to program the we will have to use another external circuit that will stand in between the PC and the microcontroller and help us to communicate back and forth between them.
Organizer 2pcs FT232RL FTDI Mini USB to TTL Serial Converter Adapter Module 3.3V 5.5V FT232R Breakout FT232RL USB to Serial Mini USB to TTL Adapter Board for Arduino $9.78 $ 9 . 78 $15.99 $15.99 Get it as soon as Tue, May 2 In B4R under board selector, choose 'Arduino Pro or pro Mini' and remember to select the correct port number. On the left is the Pro Mini, on the right is the USB to Serial module with a USB cable plugged into it, which in turn is connected to my development laptop which is powering both devices High Speed USB Controllers for Serial and FIFO Applications Based on FTDI FT232BM High-Speed USB UART IC. Supports Windows 64-bit (Vista, XP, Server 2003) 32-bit (Vista, XP, Server 2003, 2000, ME, 98), Linux, Mac OS X, Mac OS 9, Mac OS 8 “Arduino is a micro controller” this statement is technically incorrect. Arduino is a platform/board, which has a micro controller in it. Arduino boards uses a series of micro controllers that are made by a company called ATMEL. All the pins of micro controller IC are connected to the board which makes it easier for us to access the GPIO pins and program the IC.
Reading data from an Arduino's USB/serial port using Debian Linux Here is a later approach using Minicom, from a reader. Thanks Martin, I've learned something new The Arduino UNO has its own FTDI chip whose function is to convert TTL signal levels to USB. This is why you can communicate with the board serially using a USB cable and the Serial Monitor feature of the Arduino IDE
Just about everyone who is involved with serial communication will have his/her RS232 to USB converter. Today's PCs don't even bother to support RS232. Consequently, a USB converter is mandatory to monitor RS232 data traffic. All this appears to render the following project obsolete. However, when it comes to a protocol converter, i.e. the conversion of data frames, this solution might come in. Arduino MEGA 2560 and Due. Both the MEGA 2560 and Due have 4 serial ports in total. One that connects through a USB port chip to the USB device port on the board and three extra serial ports that connect to pins on one of the pin headers of the board Arduino Zero (Arduino.cc) Arduino M0 has two serial ports, M0 pro and Zero have three. Images: This is the Arduino Zero, same form as M0 pro. About Serial ports, I have to say that Arduino M0 only has the native USB port and the Serial pins 0 and 1. Differences between Serial ports: Serial port of pins 0 and 1
Data Terminal Ready (DTR) is simply a control signal in RS232 serial communication, transmitted from data terminal equipment (DTE), like a PC, to data communications equipment (DCE), for example a modem, which will be used to indicate that the terminal is ready for communications and the modem can now initiate a communication channel. Stack Exchange Network Stack Exchange network consists of 177 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. That is how we upload a code to an Arduino board especially Arduino Pro Mini with no USB port using a USB to Serial RS232 PL2303 TTL Adapter with or without a DTR pin. Bluetooth is the most popular way of connecting an Arduino to a smartphone wirelessly. In this tutorial, we will create an arduino-bluetooth interface and send messages from an arduino to smartphone and arduino to a personal computer. Bluetooth is a radio communication protocol that was created as a wireless alternative to the RS-232 serial. The CH340 chip is used by a number of Arduino compatible boards to provide USB connectivity, you may need to install a driver, don't panic, it's easier than falling off a log, and much less painful. In the Arduino IDE when the CH340 is connected you will see a COM Port in the Tools > Serial Port menu, the COM number for your device may vary. This was introduced in Arduino IDE 1.0.1. Returns true if the specified serial port is available. This will only return false if querying the Leonardo's USB CDC serial connection before it is ready. Data type: bool. void setup () { //Initialize serial and wait for port to open: Serial.begin (9600); while (!Serial) { ; // wait for serial.