Hello. I am making a wifi display using a max7219 and an esp32. I've got the basic code working, but there is an issue that I don't understand. Only one character will show up and when I send an "A", ":" gets displayed, when I send a "b", ">" will show up and only one character will show up. Do you get what I'm trying to say?
#include <WiFi.h>
#include <WiFiClient.h>
#include <WebServer.h>
#include <ESPmDNS.h>
#include <MD_Parola.h>
#include <MD_MAX72xx.h>
#include <SPI.h>
const char *ssid = "TheSecretMustNotBeRevealed";
const char *password = "SameHere";
uint8_t connectedDevices = 0;
WebServer server(80);
MD_Parola mx = MD_Parola(MD_MAX72XX::FC16_HW, 23, 18, 5, 4);
const int led = 13;
void handleRoot() {
digitalWrite(led, 1);
char temp[400];
int sec = millis() / 1000;
int min = sec / 60;
int hr = min / 60;
snprintf(temp, 400,
"<html>\
<head>\
<meta http-equiv='refresh' content='5'/>\
<title>ESP32 Demo</title>\
<style>\
body { background-color: #cccccc; font-family: Arial, Helvetica, Sans-Serif; Color: #000088; }\
</style>\
</head>\
<body>\
<h1>Hello from ESP32!</h1>\
<p>Uptime: %02d:%02d:%02d</p>\
<img src=\"/test.svg\" />\
</body>\
</html>",
hr, min % 60, sec % 60
);
server.send(200, "text/html", temp);
digitalWrite(led, 0);
}
void handleNotFound() {
digitalWrite(led, 1);
String message = "File Not Found\n\n";
message += "URI: ";
message += server.uri();
message += "\nMethod: ";
message += (server.method() == HTTP_GET) ? "GET" : "POST";
message += "\nArguments: ";
message += server.args();
message += "\n";
for (uint8_t i = 0; i < server.args(); i++) {
message += " " + server.argName(i) + ": " + server.arg(i) + "\n";
}
server.send(404, "text/plain", message);
digitalWrite(led, 0);
}
void setup(void) {
pinMode(led, OUTPUT);
pinMode(4, OUTPUT);
digitalWrite(led, 0);
Serial.begin(115200);
WiFi.mode(WIFI_STA); //WIFI_STA for non-AP mode, WIFI_AP for AP mode
WiFi.begin(ssid, password);
Serial.println("");
mx.begin();
// AP MODE
// while (!WiFi.softAP(ssid, password)) { //WiFi.status() != WL_CONNECTED
// delay(500);
// }
// non-AP MODE
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.print("Connected to ");
Serial.println(ssid);
Serial.print("IP address: ");
//Serial.println(WiFi.softAPIP());
Serial.println(WiFi.localIP());
if (MDNS.begin("esp32")) {
Serial.println("MDNS responder started");
}
server.on("/", handleRoot);
server.on("/test.svg", drawGraph);
server.on("/ledon", ledOn);
server.on("/ledoff", ledOff);
server.on("/display", displayHandler);
server.on("/msgpost", HTTP_POST, postHandler);
server.on("/inline", []() {
server.send(200, "text/plain", "this works as well");
});
server.onNotFound(handleNotFound);
server.begin();
Serial.println("HTTP server started");
}
void loop(void) {
server.handleClient();
if(connectedDevices != server.client().connected()) {
Serial.println("A page was visited");
}
connectedDevices = server.client().connected();
mx.displayAnimate();
delay(2);//allow the cpu to switch to other tasks
}
void postHandler() {
String postResult = server.arg("text");
const char *txt = postResult.c_str();
mx.displayText(txt, PA_LEFT, 50, 2000, PA_SCROLL_LEFT);
server.sendHeader("Connection", "close");
server.send(200, "text/html", "<h1>" + postResult + "</h1>");
}
void displayHandler() {
server.send(200, "text/html", "<form action=\"/msgpost\" method=\"post\"><input type=\"text\" name=\"text\"><button type=\"submit\">Display</button></form>");
}
void ledOn() {
digitalWrite(4, HIGH);
server.send(200, "text/plain", "led is ON");
}
void ledOff() {
digitalWrite(4, LOW);
server.send(200, "text/plain", "led is OFF");
}
void drawGraph() {
String out = "";
char temp[100];
out += "<svg xmlns=\"http://www.w3.org/2000/svg\" version=\"1.1\" width=\"400\" height=\"150\">\n";
out += "<rect width=\"400\" height=\"150\" fill=\"rgb(250, 230, 210)\" stroke-width=\"1\" stroke=\"rgb(0, 0, 0)\" />\n";
out += "<g stroke=\"black\">\n";
int y = rand() % 130;
for (int x = 10; x < 390; x += 10) {
int y2 = rand() % 130;
sprintf(temp, "<line x1=\"%d\" y1=\"%d\" x2=\"%d\" y2=\"%d\" stroke-width=\"1\" />\n", x, 140 - y, x + 10, 140 - y2);
out += temp;
y = y2;
}
out += "</g>\n</svg>\n";
server.send(200, "image/svg+xml", out);
}