Update examples/src/main.cpp

README.md

@@ -13,7 +13,7 @@ The CTA API can be fairly trivially queries to get a JSON response with the requ
     To query XML: https://lapi.transitchicago.com/api/1.0/ttarrivals.aspx?key=<KEYID>&mapid=<mapID>
     To query JSON: https://lapi.transitchicago.com/api/1.0/ttarrivals.aspx?key=<KEYID>&mapid=40380&outputType=JSON
 
-    Simple HTTP POST queries use the '?' to define start of parameters, and each parameter is seperated by an '&'
+    Simple HTTP queries use the '?' to define start of parameters, and each parameter is seperated by an '&'
     In the above, we are querying the 'ttarrivals' endpoint, used for the Arrivals API
     KEYID is your API key
     MAPID is the ID of a station on the CTA, such as "40380". These station numbers are available on the ttdocs website.
@@ -106,9 +106,10 @@ print(stations_eta[40390])
 ```
 
 ### ESP32 Implementation
-- Micropython appears to still be poorly documented for ESP32s (especially the aliexpress clone boards).
-- Recommendation is to use either the Arduino IDE (for quickly getting going) or using PlatformIO with VS Code.
+- Micropython, Arduino IDE and PlatformIO are the three best options
+- Easier programming - go with MicroPython
+- Simpler setup, use either the Arduino IDE (for quickly getting going) or using PlatformIO with VS Code.
     - Both of these are just fancy wrappers around C++ language, so plenty of documentation to google.
-    - The latter is harder to initially get going (mostly cause of VS Code), but it's a much nicer environment to code in than Arduino IDE.
+    - The latter is harder to initially get going (mostly cause of VS Code weirdness), but it's a much nicer environment to code in than Arduino IDE.
     - PlatformIO is completely compatable with Arduino code, so can always start in Arduino IDE and move from there.
-- Example PlatformIO code for the API is available in example/src/
+- Example Arduino IDE code for the API is available in /example/src/

examples/src/main.cpp

@@ -0,0 +1,89 @@
+#include <Arduino.h>
+#include <WiFi.h>
+#include <ArduinoJson.h>  // Include ArduinoJson library
+#include <HTTPClient.h>
+#include <time.h>
+
+const char* ssid = "OSULL";
+const char* password = "thisispassword";
+const char* APIKey = "f4b7aff25779483bba8cac91900f6efc";
+// Use HTTP instead of HTTPS for a bit more simplicity
+String serverName = "http://lapi.transitchicago.com/api/1.0/ttpositions.aspx";
+
+
+// Last run time for the loop, don't need to query too often, stored in milliseconds
+unsigned long lastTime = 0;
+// How often to update table (every 60 seconds)
+// unsigned long queryTime = 60*1000
+unsigned long queryTime = 5*1000;
+
+// How far away the train (in seconds) should be from the station to trigger
+unsigned int time_to_led = 120;
+
+void setup() {
+  Serial.begin(115200);
+  WiFi.begin(ssid, password);
+  
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(1000);
+    Serial.print("Connecting to WiFi...");
+  }
+  
+  Serial.println("Connected to WiFi!");
+  Serial.print("IP Address: ");
+  Serial.println(WiFi.localIP());
+}
+
+void loop() {
+  // Only run if we haven't run in queryTime
+  if ((millis() - lastTime) > queryTime) {
+    // Query the HTTP endpoint with a POST request and parameters, only interested in Blue route for now
+    const char* route = "Blue";
+    
+    // http object let's us query a webserver
+    HTTPClient http;
+
+    String serverPath = serverName + "?key=" + APIKey + "&rt=" + route + "&outputType=JSON";
+    http.useHTTP10(true);
+    http.begin(serverPath.c_str());
+    int httpResponse = http.GET();
+
+    // Minimum size acquired from pasting raw JSON into here: https://arduinojson.org/v5/assistant/
+    DynamicJsonDocument location_json(9128);
+    deserializeJson(location_json, http.getStream()); 
+
+    // Store time we queried server
+    const char* time_c = location_json["ctatt"]["tmst"];
+    struct tm time_tm;
+    strptime(time_c, "%Y-%m-%dT%H:%M:%S", &time_tm);
+    time_t time = mktime(&time_tm);
+
+    Serial.print("Time of query: ");
+    Serial.println(time_tm.tm_hour);
+
+    const char* nextStaID = location_json["ctatt"]["route"][0]["train"][0]["nextStaID"];
+    Serial.println(nextStaID);
+
+    // Move through the array to find 
+    for (JsonObject train : location_json["ctatt"]["route"][0]["train"].as<JsonArray>()) {
+      unsigned int nextSta = train["nextStaId"];
+      const char* arrTime = train["arrT"]; 
+      // Annoying multistep process to get ISO time into time_t format
+      struct tm eta_tm;
+      strptime(arrTime, "%Y-%m-%dT%H:%M:%S", &eta_tm);
+      time_t eta = mktime(&eta_tm);
+
+      // Save station name for pretty output
+      const char* stationName = train["nextStaNm"];
+      
+      double difference = difftime(eta, time);
+
+      if(difference < time_to_led) {
+        String output = String("Train arriving soon at ") + stationName + " in " + difference + " seconds.";
+        Serial.println(output);
+      }
+    }
+
+    lastTime = millis();
+  }
+}