ESP8266 and ESP32 WiFi capabilities in IOT Protocols - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize WiFi on ESP8266.

IOT Protocols

WiFi.begin([1]);

Drag options to blanks, or click blank then click option'

Astart()

Bconnect()

C"MySSID", "MyPassword"

Dsetup()

Attempts:

3 left

💡 Hint

Common Mistakes

Using WiFi.connect() instead of WiFi.begin()

Not providing SSID and password as strings

The WiFi.begin() function starts the WiFi connection using the SSID and password.

2fill in blank

medium

Complete the code to check if ESP32 is connected to WiFi.

IOT Protocols

if (WiFi.[1]() == WL_CONNECTED) { /* connected */ }

Drag options to blanks, or click blank then click option'

Astatus

Bbegin

Cconnect

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using WiFi.begin() to check status

Using WiFi.connect() incorrectly

The WiFi.status() function returns the current connection status.

3fill in blank

hard

Fix the error in the code to print the ESP8266 IP address.

IOT Protocols

Serial.println(WiFi.[1]());

Drag options to blanks, or click blank then click option'

AlocalIP

BipAddress

CgetIP

Daddress

Attempts:

3 left

💡 Hint

Common Mistakes

Using WiFi.ipAddress() which does not exist

Using WiFi.getIP() which is invalid

The correct function to get the IP address is WiFi.localIP().

4fill in blank

hard

Fill both blanks to create a WiFi access point with ESP32.

IOT Protocols

WiFi.softAP([1], [2]);

Drag options to blanks, or click blank then click option'

A"MyESP32AP"

B"password123"

C"SSID"

D"pass"

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping SSID and password

Using generic strings like 'SSID' or 'pass' instead of real names

The WiFi.softAP() function creates an access point with the given SSID and password.

5fill in blank

hard

Fill all three blanks to scan for WiFi networks and print their SSIDs.

IOT Protocols

int n = WiFi.[1]();
for (int i = 0; i < n; i++) {
  Serial.println(WiFi.[2](i).[3]());
}

Drag options to blanks, or click blank then click option'

AscanNetworks

BSSID

Cc_str

DgetSSID

Attempts:

3 left

💡 Hint

Common Mistakes

Using WiFi.getSSID() which does not exist

Not calling scanNetworks() before looping

WiFi.scanNetworks() returns the number of networks found.
WiFi.SSID(i) gets the SSID of the i-th network.
c_str() converts the SSID to a printable string.

Practice

1. What is the main purpose of the WiFi.begin() function on ESP8266 and ESP32 devices?

easy

A. To start connecting the device to a WiFi network

B. To disconnect the device from the WiFi network

C. To check the current WiFi connection status

D. To get the device's IP address

Solution

1. Step 1: Understand the function purpose

   WiFi.begin() is used to initiate the connection process to a WiFi network by providing the network credentials.

2. Step 2: Differentiate from other functions

   WiFi.status() checks connection status, WiFi.localIP() gets IP, and disconnecting uses WiFi.disconnect().

3. Final Answer:

   To start connecting the device to a WiFi network -> Option A

4. Quick Check:

   WiFi.begin() starts connection [OK]

Hint: Remember: begin means start connection [OK]

Common Mistakes:

• Confusing WiFi.begin() with WiFi.status()
• Thinking WiFi.begin() returns IP address
• Mixing up connect and disconnect functions

2. Which of the following is the correct way to check if the ESP32 is connected to WiFi?

easy

A. if (WiFi.connected()) { ... }

B. if (WiFi.begin() == true) { ... }

C. if (WiFi.localIP() != 0) { ... }

D. if (WiFi.status() == WL_CONNECTED) { ... }

Solution

1. Step 1: Identify the correct status check method

   The function WiFi.status() returns the connection status, and WL_CONNECTED means connected.

2. Step 2: Evaluate other options

   WiFi.connected() does not exist, WiFi.begin() starts connection but doesn't return boolean, and WiFi.localIP() returns IP object, not a number.

3. Final Answer:

   if (WiFi.status() == WL_CONNECTED) { ... } -> Option D

4. Quick Check:

   WiFi.status() == WL_CONNECTED checks connection [OK]

Hint: Use WiFi.status() to check connection status [OK]

Common Mistakes:

• Using WiFi.begin() to check connection
• Assuming WiFi.connected() exists
• Comparing IP address directly to zero

3. Given this code snippet on an ESP8266 device:

WiFi.begin("MySSID", "MyPass");
while (WiFi.status() != WL_CONNECTED) {
  delay(500);
}
Serial.println(WiFi.localIP());

What will be printed if the device successfully connects to the WiFi?

medium

A. WL_CONNECTED

B. The SSID of the WiFi network

C. The IP address assigned to the device

D. An error message

Solution

1. Step 1: Understand the code flow

   The code waits until WiFi.status() returns WL_CONNECTED, meaning connection is successful.

2. Step 2: Identify the output of WiFi.localIP()

   This function returns the device's IP address on the network, which is printed by Serial.println().

3. Final Answer:

   The IP address assigned to the device -> Option C

4. Quick Check:

   WiFi.localIP() prints IP address [OK]

Hint: WiFi.localIP() shows device IP after connection [OK]

Common Mistakes:

• Expecting SSID instead of IP
• Thinking WiFi.status() prints status automatically
• Confusing connection status with output

4. You wrote this code to connect ESP32 to WiFi:

WiFi.begin("HomeNetwork", "password123");
if (WiFi.status() = WL_CONNECTED) {
  Serial.println("Connected!");
}

Why does this code fail to print "Connected!" even when WiFi is connected?

medium

A. Because Serial.println() cannot print strings

B. Because the assignment operator '=' is used instead of '==' in the if condition

C. Because WiFi.status() returns a string, not a constant

D. Because WiFi.begin() must be called inside the if statement

Solution

1. Step 1: Identify the error in the if condition

   The code uses '=' which assigns value instead of '==' which compares values. This causes a logic error.

2. Step 2: Understand the impact on execution

   Because of assignment, the condition does not properly check connection status, so "Connected!" is never printed.

3. Final Answer:

   Because the assignment operator '=' is used instead of '==' in the if condition -> Option B

4. Quick Check:

   Use '==' to compare in if conditions [OK]

Hint: Use '==' for comparison, not '=' [OK]

Common Mistakes:

• Using '=' instead of '==' in conditions
• Calling WiFi.begin() inside if statement
• Misunderstanding Serial.println() capabilities

5. You want your ESP32 to connect to WiFi and print its IP address only after a successful connection, but also retry connection up to 5 times with 1 second delay each. Which code snippet correctly implements this?

hard

A. int retries = 0;
WiFi.begin("SSID", "pass");
while (WiFi.status() != WL_CONNECTED && retries < 5) {
delay(1000);
retries++;
}
if (WiFi.status() == WL_CONNECTED) {
Serial.println(WiFi.localIP());
}

B. WiFi.begin("SSID", "pass");
for (int i = 0; i < 5; i++) {
if (WiFi.status() == WL_CONNECTED) {
Serial.println(WiFi.localIP());
break;
}
delay(1000);
}

C. WiFi.begin("SSID", "pass");
while (WiFi.status() != WL_CONNECTED) {
delay(1000);
}
Serial.println(WiFi.localIP());

D. WiFi.begin("SSID", "pass");
int retries = 0;
while (retries < 5) {
if (WiFi.status() == WL_CONNECTED) {
Serial.println(WiFi.localIP());
break;
}
retries++;
delay(1000);
}

Solution

1. Step 1: Analyze retry logic with condition and counter

   int retries = 0; WiFi.begin("SSID", "pass"); while (WiFi.status() != WL_CONNECTED && retries < 5) { delay(1000); retries++; } if (WiFi.status() == WL_CONNECTED) { Serial.println(WiFi.localIP()); } uses a while loop that checks connection status and retries count, delaying 1 second each time, stopping after 5 tries or success.

2. Step 2: Confirm printing IP only after successful connection

   int retries = 0; WiFi.begin("SSID", "pass"); while (WiFi.status() != WL_CONNECTED && retries < 5) { delay(1000); retries++; } if (WiFi.status() == WL_CONNECTED) { Serial.println(WiFi.localIP()); } prints IP only if WiFi.status() == WL_CONNECTED after retry loop, meeting requirements.

3. Final Answer:

   Option A correctly implements retry with delay and prints IP after connection -> Option A

4. Quick Check:

   Retry loop with condition and counter works best [OK]

Hint: Use while loop with counter for retries [OK]

Common Mistakes:

• Not limiting retries causing infinite loops
• Printing IP before confirming connection
• Using for loop without checking connection inside