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--- en:iot-open:remotelab:sut:generalpurpose2:u2 [2019/10/29 22:04] – pczekalski
+++ en:iot-open:remotelab:sut:generalpurpose2:u2 [2020/07/20 12:00] (current) – external edit 127.0.0.1
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+==== U2: Exposing access point (AP)====
+In this scenario, you set up your own access point. Please note, in this case, a number of devices you can connect to the AP is really limited. VRELs 1, 2, 3 and 4 are physically located together, while VREL 6 and VREL 7 are in two remote locations, thus you may not be able to reach hosted AP.
+=== Target group ===
+Undergraduate / Bachelor / Engineering Students
+=== Prerequisites ===
+You need to know how to handle 4×20 characters LCD screen. In case of doubt re-work on scenarios B1 and B2.\\ <fc #ff0000>Warning: In no case should you give your AP the ''internal.IOT'' SSID name! You will mess up the laboratory environment and block other users from accessing network infrastructure. We consider this behaviour as hacking and it will be penalized under legal jurisdiction!</fc>
+<note warning>In no case give your AP the ''internal.IOT'' SSID! You will mess up the laboratory environment and block other users from accessing network infrastructure. We consider this behaviour as hacking and it will be penalized under legal jurisdiction!</note>
+To fully experience this scenario, you need to book another node (one of 1,2,3 or 4), to let the other node act as your networking client. You can use scenario U1 for this purpose but mind to update network SSID and passphrase in your code, to let it connect to your server. <note tip>Students physically present in the SUT IoT laboratory room 320 may use their own devices like laptops or mobile phones to connect to your AP.</note>
+=== Scenario ===
+In this scenario, you will set up an access point and present on the LCD screen number of clients connected. The devices that connect to your AP obtain automatically an IP address from your AP so actually it hosts a DHCP server out of the box! The IP range is from the ''192.168.4.x'' subnet, but you can configure it for another one if you only wish via ''wifi.ap.shcp.config()'' function. if you use the default configuration, your AP is 192.168.4.1.
+=== Result ===
+On the LCD you should present that AP is active, its name (SSID) and passphrase (select one no longer than 20 characters, to fit single line). In the last line of the LCD, there should be present a number of connected devices.
+=== Start ===
+Define some identifiers to separate and update AP's SSID and passphrase easily. To format lines for the LCD, we suggest using a char buffer of 20 characters (one full line) and some 2-3 integers for iterators. Remember to declare the LCD control class in your code. You do not need to instantiate WiFi communication class - as you have only one interface here, it is singleton class you can refer directly using ''WiFi''. you will use ''loop()'' to display a number of connected devices to your network. There do exist asynchronous way (event-based) to do it, but here we use a simplified, blocking approach. If you want to test the other one, refer to the ESP8266 WiFi implementation for Arduino documentation.
+=== Steps ===
+Following steps do not present full code - you need to supply missing parts on your own!
+== Step 1 ==
+Include all necessary libraries. The minimum set here is:
+<code c>
+#include <Arduino.h>
+#include <ESP8266WiFi.h>
+#include <LiquidCrystal_I2C.h>
+...
+</code>
+== Step 2 ==
+Give it some definitions as identifiers for cleaner code, remember to change ssid name to yours!
+<code c>
+#define wifi_ssid_ap put_your_unique_id_here //give it some unique name-change here
+#define wifi_password_ap "1234567890"
+</code>
+<note warning>Never use ''internal.IOT'' as your SSID name ''wifi_ssid_ap'' - you will overlap existing network infrastructure and we consider it as hacking that is subject to jurisdiction! Your account will be imediatelly banned!</note>
+== Step 3 ==
+Print some information about starting software WiFi AP, configure network interface as a WiFi AP and give it a try to start:
+<code c>
+...
+  delay(10);
+...
+  WiFi.mode(WIFI_AP);
+  delay(100);
+  boolean result = WiFi.softAP(wifi_ssid_ap, wifi_password_ap);
+  if(result == true)
+  {
+... //Announce success, print status, SSID and passphrase to the LCD
+  }
+  else
+  {
+... //Announce failure. Print it on LCD
+  }
+...
+</code>
+== Step 4 ==
+Implement in the ''loop()'' an information about number of connected clients, i.e. like this:
+<code c>
+...
+void loop()
+{
+  lcd.setCursor(0,3);
+  sprintf(buffer, "Stations: %d", WiFi.softAPgetStationNum());
+  lcd.print(buffer);
+  delay(3000);
+}
+...
+</code>
+=== Result validation ===
+Check your AP is active on LCD eventually observe failure. If works OK, compile U1 scenario on another node(s), mind to update SSID and passphrase in the U1 source code then observe if connected clients counter increases.
+=== FAQ ===
+Do I need to use WiFi.mode(WIFI_AP);?: Yes, please do. Theoretically, if consecutive compilations use AP (software server) mode of the ESP8266 wifi interface, your code may work without it. However, you never know if the previous user used STA or AP (or both). Your code may fail then if not explicitly stated!