WiFi with ESP8266/ESP32 in Arduino - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to include the WiFi library for ESP8266.

Arduino

#include <[1]>

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

AWiFi.h

BESP8266WiFi.h

CWiFiClient.h

DESP32WiFi.h

Attempts:

3 left

💡 Hint

Common Mistakes

Including the generic WiFi library instead of the ESP8266 specific one.

Using ESP32 library for ESP8266.

The ESP8266 requires the ESP8266WiFi.h library to manage WiFi connections.

2fill in blank

medium

Complete the code to connect to a WiFi network using SSID and password.

Arduino

WiFi.begin([1], password);

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

A"mySSID"

BmySSID

Cssid

D"password"

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable names without quotes.

Using the password instead of SSID.

The SSID must be a string literal enclosed in double quotes.

3fill in blank

hard

Fix the error in the code to check if WiFi is connected.

Arduino

if (WiFi.[1]() == WL_CONNECTED) {

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

Astatus

BisConnected

Cconnect

Dbegin

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'connect' or 'begin' which start connections, not check status.

Using 'isConnected' which does not exist.

The correct function to check WiFi connection status is status().

4fill in blank

hard

Fill both blanks to print the local IP address after connecting to WiFi.

Arduino

Serial.println(WiFi.[1]());
Serial.print("IP Address: ");
Serial.println(WiFi.[2]());

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

Astatus

BlocalIP

CmacAddress

DSSID

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'macAddress' or 'SSID' instead of 'localIP'.

Not checking connection status before printing IP.

First, check connection status with status(). Then get the IP with localIP().

5fill in blank

hard

Fill all three blanks to create a WiFi access point with SSID and password, then print its IP.

Arduino

WiFi.softAP([1], [2]);
Serial.print("AP IP: ");
Serial.println(WiFi.[3]());

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

A"MyESP32AP"

B"12345678"

CsoftAPIP

DlocalIP

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'localIP' instead of 'softAPIP' for access point IP.

Not using quotes around SSID and password.

Use softAP with SSID and password strings, then get the access point IP with softAPIP().

Practice

1. What is the main purpose of WiFi.begin(ssid, password) in ESP8266/ESP32 programming?

easy

A. To start connecting the device to a WiFi network

B. To disconnect from the current WiFi network

C. To check the current WiFi signal strength

D. To get the IP address of the device

Solution

1. Step 1: Understand the function purpose

   WiFi.begin(ssid, password) is used to initiate connection to a WiFi network using the given network name (SSID) and password.

2. Step 2: Compare with other options

   Disconnecting, checking signal strength, or getting IP address are done by other functions, not WiFi.begin.

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 begin with disconnect
• Thinking it returns IP address
• Assuming it checks signal strength

2. Which of the following is the correct syntax to check if the ESP8266 is connected to WiFi?

easy

A. if (WiFi.connected())

B. if (WiFi.checkConnection())

C. if (WiFi.isConnected())

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

Solution

1. Step 1: Recall the correct method to check WiFi connection

   The standard way is to use WiFi.status() and compare it to WL_CONNECTED to confirm connection.

2. Step 2: Verify other options

   Methods like WiFi.connected(), WiFi.isConnected(), or WiFi.checkConnection() do not exist in the ESP8266 WiFi library.

3. Final Answer:

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

4. Quick Check:

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

Hint: Use WiFi.status() with WL_CONNECTED constant [OK]

Common Mistakes:

• Using non-existent methods like WiFi.connected()
• Confusing status check syntax
• Forgetting to compare with WL_CONNECTED

3. What will the following code print if the ESP8266 successfully connects to WiFi?

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

medium

A. The IP address assigned to the ESP8266

B. The SSID of the WiFi network

C. The WiFi password

D. Nothing, it will cause an error

Solution

1. Step 1: Analyze the connection loop

   The code waits until WiFi.status() returns WL_CONNECTED, meaning the device is connected to WiFi.

2. Step 2: Understand the output command

   WiFi.localIP() returns the IP address assigned to the device by the router, which is printed to Serial.

3. Final Answer:

   The IP address assigned to the ESP8266 -> Option A

4. Quick Check:

   WiFi.localIP() prints device IP [OK]

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

Common Mistakes:

• Thinking it prints SSID or password
• Assuming it prints connection status
• Believing it causes an error

4. Identify the error in this ESP32 WiFi connection code:

WiFi.begin(ssid, password);
while (WiFi.status() = WL_CONNECTED) {
  delay(1000);
}
Serial.println("Connected!");

medium

A. Missing WiFi.begin() call

B. Incorrect delay value

C. Using single '=' instead of '==' in the while condition

D. No Serial.begin() before printing

Solution

1. Step 1: Check the while loop condition

   The condition uses a single '=' which is an assignment, not a comparison. It should be '==' to compare values.

2. Step 2: Confirm other parts

   WiFi.begin() is called, delay is valid, and Serial.begin() is not shown but not the main error here.

3. Final Answer:

   Using single '=' instead of '==' in the while condition -> Option C

4. Quick Check:

   Use '==' for comparison in conditions [OK]

Hint: Use '==' to compare, '=' assigns value [OK]

Common Mistakes:

• Confusing '=' with '==' in conditions
• Ignoring Serial.begin() setup
• Assuming delay value causes error

5. You want your ESP32 to connect to WiFi and print its IP address only after a successful connection, but also stop trying after 10 seconds if it fails. Which code snippet correctly implements this?

hard

A. WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
if (millis() > 10000) break;
}
Serial.println(WiFi.localIP());

B. WiFi.begin(ssid, password);
unsigned long start = millis();
while (WiFi.status() != WL_CONNECTED && millis() - start < 10000) {
delay(500);
}
if (WiFi.status() == WL_CONNECTED) {
Serial.println(WiFi.localIP());
} else {
Serial.println("Failed to connect");
}

C. WiFi.begin(ssid, password);
for (int i = 0; i < 20; i++) {
if (WiFi.status() == WL_CONNECTED) break;
delay(500);
}
Serial.println(WiFi.localIP());

D. WiFi.begin(ssid, password);
while (WiFi.status() == WL_CONNECTED) {
delay(10000);
}
Serial.println(WiFi.localIP());

Solution

1. Step 1: Understand the timeout logic

   WiFi.begin(ssid, password); unsigned long start = millis(); while (WiFi.status() != WL_CONNECTED && millis() - start < 10000) { delay(500); } if (WiFi.status() == WL_CONNECTED) { Serial.println(WiFi.localIP()); } else { Serial.println("Failed to connect"); } uses millis() to track elapsed time and stops trying after 10 seconds (10000 ms) if not connected.

2. Step 2: Check connection and print accordingly

   It prints the IP only if connected; otherwise, it prints a failure message. This matches the requirement exactly.

3. Final Answer:

   The code with 10-second timeout using millis() and conditional IP printing -> Option B

4. Quick Check:

   Use millis() for timeout and check status before printing [OK]

Hint: Use millis() to limit connection wait time [OK]

Common Mistakes:

• Not stopping connection attempts after timeout
• Printing IP without checking connection
• Using wrong while condition logic