WiFi < IoT_Course_English

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---+ Connecting to !WiFi
---++ Exercise 1:

Verify the available access points before the activation of the ESP32 WiFi.<br />Study the [[https://docs.micropython.org/en/latest/library/network.WLAN.html?highlight=wlan][MicroPython documentation on the WLAN class]].<br /><br />
   * Configure the !WiFi interface as an access point.
   * Check if the interface is already active and activate it, if not. Confirm that activation succeeded. If activation fails, emit an error message.
| !WiFi network before activation of the ESP32 access point | !WiFi after activation |
| <img alt="noESP32_AP.png" height="462" src="%ATTACHURL%/noESP32_AP.png" title="noESP32_AP.png" width="476" /> | <img alt="withESP32_AP.png" height="462" src="%ATTACHURL%/withESP32_AP.png" title="withESP32_AP.png" width="476" /> |
Connect the PC to the new access point and verify that communication works using ping.

<img alt="ap_ping.png" height="211" src="%ATTACHURL%/ap_ping.png" title="ap_ping.png" width="696" />

---++ Exercise 2:
   * Configure the ESP32 as "station interface"
   * Verify if the interface is active, activate it if not.
   * Scan the network and print all available information about the SSIDs found in a tabular format
   * Connect the ESP32 with the router specifying the SSID and the password
   * Verify that the connection was successful. (This may take a few seconds. Wait up to 10 s for the connection to be established)
   * Print the IP address assigned to your ESP32
   * Print the MAC address of the ESP32 !WiFi interface
   * Verify with ping that the ESP32 is accessible
Here is a screen dump of the solution:

<img alt="solution_ex2.png" height="248" src="%ATTACHURL%/solution_ex2.png" title="solution_ex2.png" width="909" />

This is what you will see if you try to ping the ESP32:

<img alt="sta_ping.png" height="190" src="%ATTACHURL%/sta_ping.png" title="sta_ping.png" width="691" />

You can try ping also on the ESP32:

<verbatim>from uping import ping  
ping("the machine_to_be-checked")</verbatim>
---++ Exercise 3:

Write a module: wifi.py which encapsulates the functionality of exercise 2. Upload the module to the /lib folder on the ESP32.

The code connecting to the ESP32 will then be as simple as this:
<literal>from&nbsp;wifi&nbsp;import <br />connect() &nbsp;</literal>

<img alt="wifi_connect.py.png" height="192" src="%ATTACHURL%/wifi_connect.py.png" title="wifi_connect.py.png" width="709" />

---++ Exercise 4 :

Add a function returning the ESP32's IP address.

Read the current UTC time from the network using NTP. Set the real time clock on the ESP32. Provide a function that converts UTC into your local time.
---++ Exercise 5 :

Write a TCP server and a client program running both on the PC. The server waits for a connection request from the client on port 5000, accepts it and sends a message to the client. After that, a prompt appears on the client and the user can type a message to be sent to the server. The server prints this message and creates a prompt on its side, where a message can be entered, to be sent to the client. A ping-pong communication is started. Typing the message "bye" on the client side terminates the connection.

<img alt="client-server.png" src="%ATTACHURL%/client-server.png" title="client-server.png" />
---++ Exercise 6 :
   * Move the server to the ESP32. In this case, the !WiFi initialization is needed before starting the server part. Test the communication as you did in exercise 5.
   * Move the client to the ESP32 and run the server on the PC.
---++ Exercise 7 :

Write a client on the ESP32 which reads the temperature and humidity from the DHT11 every 5s and packs the result into a message of the following form:<br />temperature [°C]: 25,humidity [%]: 56<br />Send this message to a server on the PC

The server parses the message and extracts the parameter names (temperature [°C] and humidity [%]) and the values and plots them in a dynamic plot created with matplotlib. The parameter names are used for the legend, the values are displayed graphically.

<img alt="dht11Plot.png" height="586" src="%ATTACHURL%/dht11Plot.png" title="dht11Plot.png" width="672" />

In the above plot, I put a finger on the DHT11, which quickly increases the measured humidity and more slowly increases the temperature.

-- %USERSIG{UliRaich - 2022-08-29}%

---++ Comments

%COMMENT%

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who
png	ap_ping.png	r1	manage	61.1 K	2022-08-29 - 08:09	UliRaich
png	client-server.png	r1	manage	199.2 K	2022-09-04 - 08:17	UliRaich
png	dht11Plot.png	r1	manage	31.3 K	2022-09-25 - 08:36	UliRaich
png	noESP32_AP.png	r1	manage	20.4 K	2022-08-29 - 08:09	UliRaich
png	solution_ex2.png	r2 r1	manage	71.0 K	2022-09-03 - 19:52	UliRaich
png	sta_ping.png	r2 r1	manage	52.7 K	2022-09-04 - 08:48	UliRaich
png	wifi_connect.py.png	r1	manage	20.9 K	2022-08-29 - 08:28	UliRaich
png	withESP32_AP.png	r1	manage	22.0 K	2022-08-29 - 08:09	UliRaich

Topic revision: r5 - 2022-09-25 - UliRaich