Add matrixDisplay example

examples/matrixDisplay/Makefile

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+#!/usr/bin/make -f
+# SPDX-License-Identifier: MPL-2.0
+#{
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/
+#}
+
+default: all
+	@echo "# $@: $^"
+
+top_reldir?=../..
+topdir?=${CURDIR}/${top_reldir}
+
+-include ${topdir}/Makefile
+
+AVR_TOOLS_DIR?=${ARDUINO_DIR}/hardware/tools/avr
+ARDUINO_DIR?=/usr/share/arduino
+ARDMK_DIR?=${ARDUINO_DIR}
+arduino_mk?=${ARDMK_DIR}/Arduino.mk
+
+#{ Config part
+VARIANT?=mega
+BOARD_TAG=mega2560
+BOARD_SUB=
+MCU?=at${BOARD_TAG}
+F_CPU?=16000000L
+MONITOR_PORT?=$(shell ls /dev/ttyUSB* 2> /dev/null \
+	|| ls /dev/ttyACM* 2> /dev/null \
+	|| echo "/dev/TODO/setup/monitor" \
+	| sort | head -n1)
+#}
+
+ARCHITECTURE=avr
+AVRDUDE_ARD_BAUDRATE?=115200
+MONITOR_BAUDRATE?=${AVRDUDE_ARD_BAUDRATE}
+AVRDUDE_ARD_PROGRAMMER?=wiring
+
+CPPFLAGS+=-I${top_reldir}
+
+ARDUINO_LIBS += Ethernet SPI
+ARDUINO_LIBS += ArduinoMDNS
+ARDUINO_LIBS += ArduinoJson
+ARDUINO_LIBS += WiFi101
+ARDUINO_LIBS += Wire
+ARDUINO_LIBS += Adafruit_GFX
+ARDUINO_LIBS += Adafruit_SSD1306
+
+-include ${arduino_mk}
+
+rule/setup:
+	@echo "Please setup your env to use ${arduino_mk}"
+
+%: rule/setup
+	@echo "Please run \"make $@\" again"

examples/matrixDisplay/README.md

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+## Matrix Display example
+
+You need to install the WebThings Arduino library in order to use this example.
+
+Change the ssid and password to connect to your router
+
+```c++
+const char *ssid = "";
+const char *password = "";
+```
+
+If you want to use more than four matrix displays, you can just change the value of `MAX_DEVICES`
+
+```c++
+#define MAX_DEVICES 4
+```
+
+If you use another PIN than PIN 5 as CS, you have to change it in the code before
+
+```c++
+#define CS_PIN 5
+```
+
+The SPI matrix display has to be connected to VSPI of the ESP32.
+
+|  ESP32 Pin  |   | MAX7219 Matrix |
+|-------------|---|----------------|
+| VCC (3.3V)  | → |    VCC (VDD)   |
+|     GND     | → |       GND      |
+|  D23 (IO23) | → |   DIN (MOSI)   |
+|   D5 (IO5)  | → |     CS (SS)    |
+|  D18 (IO18) | → |       CLK      |

examples/matrixDisplay/matrixDisplay.ino

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+/**
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+#include <MD_Parola.h>
+#include <MD_MAX72xx.h>
+#include <SPI.h>
+#include <Arduino.h>
+#include <Thing.h>
+#include <WebThingAdapter.h>
+
+#define LARGE_JSON_BUFFERS 1
+
+#define HARDWARE_TYPE MD_MAX72XX::FC16_HW
+#define MAX_DEVICES 4
+#define CS_PIN 5
+
+MD_Parola myDisplay = MD_Parola(HARDWARE_TYPE, CS_PIN, MAX_DEVICES);
+
+// TODO: Hardcode your wifi credentials here (and keep it private)
+const char *ssid = "";
+const char *password = "";
+
+#if defined(LED_BUILTIN)
+const int ledPin = LED_BUILTIN;
+#else
+const int ledPin = 13; // manually configure LED pin
+#endif
+
+ThingActionObject *action_generator(DynamicJsonDocument *);
+WebThingAdapter *adapter;
+
+const char *displayTypes[] = {"Matrix Display", nullptr};
+ThingDevice displayThing("matrixDisplay", "Matrix Display", displayTypes);
+
+StaticJsonDocument<256> displayInput;
+JsonObject displayInputObj = displayInput.to<JsonObject>();
+ThingAction displayAction("display", "Display text", "display a text on a Matrix display",
+                 "displayAction", &displayInputObj, action_generator);
+
+void setup() {
+  Serial.begin(115200);
+  Serial.println("Initialize...");
+  myDisplay.begin();
+  myDisplay.setIntensity(0);
+  Serial.println("Clear display...");
+  myDisplay.displayClear();
+
+  pinMode(ledPin, OUTPUT);
+  digitalWrite(ledPin, HIGH);
+  Serial.println("");
+  Serial.print("Connecting to \"");
+  Serial.print(ssid);
+  Serial.println("\"");
+#if defined(ESP8266) || defined(ESP32)
+  WiFi.mode(WIFI_STA);
+#endif
+  WiFi.begin(ssid, password);
+
+  bool blink = true;
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+    digitalWrite(ledPin, blink ? LOW : HIGH);
+    blink = !blink;
+  }
+  digitalWrite(ledPin, HIGH);
+
+  Serial.println("");
+  Serial.print("Connected to ");
+  Serial.println(ssid);
+  Serial.print("IP address: ");
+  Serial.println(WiFi.localIP());
+
+  adapter = new WebThingAdapter("matrix-display", WiFi.localIP());
+  displayThing.description = "A web connected matrix display";
+
+
+  displayInputObj["type"] = "object";
+    JsonObject displayInputProperties =
+      displayInputObj.createNestedObject("properties");
+
+
+  JsonObject bodyInput =
+      displayInputProperties.createNestedObject("body");
+  bodyInput["type"] = "string";
+
+  displayThing.addAction(&displayAction);
+
+  adapter->addDevice(&displayThing);
+  adapter->begin();
+}
+
+#define BODY_MAX_LENGTH 200
+#define MAX_WO_SCROLLING 6
+
+char body[BODY_MAX_LENGTH];
+bool scrolling = false;
+
+void clear_buffer(){
+  memset(body, 0, BODY_MAX_LENGTH);
+  scrolling = false;
+}
+
+int rounds = 0;
+
+void loop() 
+{
+  if(strlen(body) > 0){
+    myDisplay.displayClear();
+    myDisplay.setTextAlignment(PA_LEFT);
+
+    myDisplay.print(body);
+    rounds = 1;
+    clear_buffer();
+  }else if(rounds > 0){
+      //To avoid burning, clear after 30 seconds.
+      if(rounds == 300){
+          myDisplay.displayClear();
+          rounds = 0;
+      }else{
+          delay(100);
+          rounds++;
+      }
+  }
+}
+
+void do_display(const JsonVariant &input) {
+  Serial.println("do display...");
+  clear_buffer();
+
+  JsonObject inputObj = input.as<JsonObject>();
+  myDisplay.displayClear();
+  String body_tmp = inputObj["body"];
+
+  size_t length = strlen(body_tmp.c_str());
+  if(length > BODY_MAX_LENGTH){
+      Serial.println("Body is too long");
+      return;
+  } else{
+      memcpy(body, body_tmp.c_str(), length);
+  }
+}
+
+ThingActionObject *action_generator(DynamicJsonDocument *input) {
+  return new ThingActionObject("display", input, do_display, nullptr);
+}