/* * AnalogReadToWaveformCode.ino - Simple example code for EasyNextionLibrary * Copyright (c) 2020 Athanasios Seitanis < seithagta@gmail.com >. * https://www.seithan.com * All rights reserved. EasyNextionLibrary is licensed under the MIT License * https://opensource.org/licenses/MIT */ /* I have invested time and resources providing open source codes, like this one. * Please do not hesitate to support my work! * If you found this work useful and has saved you time and effort, * Just simply paypal me at: seithagta@gmail.com */ //******************************************************************************** // You can find more examples, tutorials and projects with Nextion on my website // https://www.seithan.com //******************************************************************************** /* This example aims to show how you can use and manage single waveform * on Nextion displays. As an example we are going to display the value of an analog input. * With the same way you can manage more than one channels or waveforms */ /* Every waveform can have up to 4 channels. They are numbered from 0 to 3 * Don't mistake the number of channels with the ID of the channel * ID is 0 for the first channel, 1 for the second, 2 for the third, 3 for the fourth */ //********** Waveform's channel data range is min 0 max 255 ********** // **** A re-map of value range must de done **** /* The command to Add single value to Waveform Channel is: * add ,, * is the .id of the waveform component * is the channel the data will be added to * is ASCII text of data value, or numeric value */ /* TIP: Waveform 1 pixel column used for every data value added on x - axis * on y - axis as the Data range is from 0 to 255 the height of waveform must be 255 pixel * in order to have a represent of zero to the lower point and 255 to the higher point of the waveform * If the height of the waveform is not 255 pixel use the * dis * attribute for scaling the data from 10 to 1000% * if waveform has a height of 127 pixel set data scaling * dis * to 50. Set dis to 200 for 510 pixel waveform height * You can use this math type < dis = 100*(waveform height in pixels)/255 > */ /* There is no need to send from Arduino the command add ,, * as most times the waveform is not the only component on a page that must be updated * usually the display of the value on a box also needed * On some cases a change of color on a box also needed when value reach a point. * As the value to waveform must be re-mapped to 0-255 and in order to not send the same value multiple times * with different formats and limit the data from Serial, use the advantages of Nextion graphics to * create a variable and save there the value you want to appear in the waveform. * Use the features provided by Nextion via the user code on a timer to update the waveform * and at the same time display the value or whatever else you need */ #include "EasyNextionLibrary.h" // Include EasyNextionLibrary EasyNex myNex(Serial); // Create an object of EasyNex class with the name < myNex > // Set as parameter the Hardware Serial you are going to use uint16_t voltageGraph; // a variable to store the reading // for simplicity reasons, we do not use float and we are going to take the measure in millivolts const int REFRESH_TIME = 100; // time to refresh the Nextion page every 100 ms unsigned long refresh_timer = millis(); // timer for refreshing Nextion's page void setup() { pinMode(A0, INPUT); // set A0 pin as INPUT myNex.begin(9600); // Begin the object with a baud rate of 9600 // If no parameter was given in the begin(), the default baud rate of 9600 will be used } void loop() { if((millis()-refresh_timer) > REFRESH_TIME){ //IMPORTANT do not have serial print commands in the loop without a delay // or an if statement with a timer condition like this one. int tempData = analogRead(A0); // Read the analog pin voltageGraph = map(tempData, 0, 1024, 0, 5000); // same like: voltageGraph = analogRead(A0)*5000/1024 /* We Re-map the value of tempData from 0-1024 (steps) to 0-5000 millivolt * connect the pins of a Potentiometer on A0 pin, 5v (5000 millivolt) and GND. Outer pins to 5v and GND, middle pin to A0 * https://www.arduino.cc/en/tutorial/potentiometer * Turn it over and read values from 0 to 5000 millivolts */ myNex.writeNum("NvoltageGraph.val", voltageGraph); // NvoltageGraph.val is a variable that we have create on Nextion. // we send the value of the voltageGraph variable on Arduino // you can use the same name for variables on Nextion for easy recognition with a capital N infront // Avoid the use of big variable names as every character is one byte to serial. // In here we use big names for the sake of the example. refresh_timer = millis(); // Set the timer equal to millis, create a time stamp to start over the "delay" } } /* The rest work is on Nextion with the code on a timers user event sys0=NvoltageGraph.val*255/5000 // use sys0 to make the calculations add 2,0,sys0 // add the value to the waveform with id=2 at first channel (0) n0.val=NvoltageGraph.val // write NvoltageGraph.val to n0.val // // Waveform can take values from 0-250 // we map the value from arduino 0-5000 : // the math type for map the range is: // return = (value - low1) * (high2 - low2) / (high1 - low1) + low2 // as both ranges start from zero low1 and low2 = 0 // the type becomes // return = value*hight2/hight1 // return=value*255/5000 // // And some graphic effects if(n0.val>3300) { n0.bco=RED }else { n0.bco=YELLOW } */