CSV format data logging in Arduino - Step-by-Step Execution

Concept Flow - CSV format data logging

Start Program

↓

Initialize Sensors

↓

Read Sensor Data

↓

Format Data as CSV

↓

Write Data to Storage

↓

Repeat at Interval

↓

Stop or Continue Loop

The program starts, reads sensor data, formats it as CSV, writes it to storage, and repeats this cycle.

Execution Sample

Arduino

void loop() {
  int temp = analogRead(A0);
  int hum = analogRead(A1);
  Serial.print(temp);
  Serial.print(",");
  Serial.println(hum);
  delay(1000);
}

Reads two sensor values, prints them as CSV to serial every second.

Execution Table

Step	Action	temp Value	hum Value	CSV Output	Delay
1	Read temp sensor	523
2	Read hum sensor	523	487
3	Print temp	523	487	523
4	Print comma	523	487	523,
5	Print hum with newline	523	487	523,487
6	Wait 1000 ms	523	487	523,487	1000 ms
7	Repeat loop

💡 Loop runs continuously; no exit unless powered off.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 5	Final
temp	undefined	523	523	523	523
hum	undefined	undefined	487	487	487
CSV Output	""	""	""	523,487	523,487

Key Moments - 3 Insights

Why do we print a comma between sensor values?

The comma separates values in CSV format, so each sensor reading is a separate column. See execution_table steps 3 and 4.

Why use println for the last value instead of print?

println adds a newline, ending the CSV row. This ensures each data set is on its own line. See execution_table step 5.

What happens if delay is removed?

Without delay, data prints too fast, making it hard to read or store properly. See execution_table step 6 for timing.

Visual Quiz - 3 Questions

Look at the execution_table, what is the CSV output after step 5?

A 523;487

B 523487

C 523,487

D 523 487

💡 Hint

Check the CSV Output column at step 5 in the execution_table.

At which step is the humidity sensor value read?

A Step 2

B Step 3

C Step 1

D Step 4

💡 Hint

Look at the 'Action' column for sensor reads in the execution_table.

If the delay(1000) is changed to delay(500), what happens to the data logging speed?

A Data logs half as fast

B Data logs twice as fast

C Data logging stops

D No change in speed

💡 Hint

Refer to the Delay column in execution_table step 6 and think about timing.

Concept Snapshot

CSV Data Logging in Arduino:
- Read sensor values (e.g., analogRead)
- Print values separated by commas
- End each line with println for new row
- Use delay to control logging frequency
- Output is easy to import into spreadsheets

Full Transcript

This lesson shows how Arduino reads sensor data and logs it in CSV format. The program reads temperature and humidity sensors, prints their values separated by a comma, and ends the line with a newline character. This creates rows of data that can be saved or viewed in serial monitor. A delay controls how often data is logged. The execution table traces each step: reading sensors, printing values, and waiting. Key points include why commas separate values and why println ends the line. The quiz tests understanding of output format, sensor reading steps, and timing effects.