Light Meter Logger Kit

Classes 7-8, typical ages 12–14. Age ranges vary by learner. Guided low-voltage electronics.

Activity engagement

60–90 minutes. Explore 10–15 min · Build 20–30 min · Test and discuss 30–45 min. Estimated time for building, testing and discussion.

What you need

A computer with a USB port and Arduino IDE is required and is not included.

Included components

• Small Breadboard / Mini Solderless Board - 400 points — 1 breadboard
• Jumper Wire Combo - Male to Male, Male to Female and Female to Female Breadboard Connecting Wires (10 Qty Each) — 1 set
• Illustrated Activity Guide and Observation Sheets — 1 set
• Fitted Headers and Labelled Connection Leads — 1 set
• Arduino Uno R3 CH340G version compatible Arduino Development Board — 1 controller board
• USB A to B Programming Cable for Arduino Uno/ Arduino Mega — 1 data cable
• LDR Sensor (Light Dependent Resistor) - 5mm — 1 photoresistor
• 10K Ω 1/4 Watts (10 PCS) — 1 resistor

What you learn

• An LDR changes resistance with light.
• A voltage divider converts resistance change to voltage.
• Raw readings are relative; they are not calibrated lux.

Connection guide

• 5 V → LDR → A0 node → 10 kOhm → GND.

Steps to make it

1. Disconnect all power and identify the supplied part labels and pinouts before wiring.
2. Build the divider and upload the sketch.
3. Open Serial Plotter and observe the baseline for ten seconds.
4. Cover the LDR, uncover it, then illuminate it with a room lamp at two distances.
5. Copy the serial CSV into a spreadsheet and annotate the conditions.
6. Change only the named parameter for the extension, repeat the controlled trials, save observations and disconnect power afterward.

Programming resources

Arduino IDE: select Arduino Uno and the USB port. Use the supplied USB data cable. Serial Monitor/Plotter: 115200 baud.

Uses the selected board core libraries.

Download starter sketch

Test challenge

Collect ten readings per condition without changing the circuit.

Observation task

Elapsed milliseconds, raw ADC count and light condition.

Expected result

In this divider orientation brighter light normally increases ADC readings.

If it does not work

An unconnected A0 pin floats. Reverse sensor/resistor order only when deliberately testing an inverted response.

Try next

Calibrate a relative 0–100 scale using your own dark and bright references.

Use and supervision

Use only the supplied low-voltage DC parts. Disconnect power before rewiring; check polarity and labelled pinouts. No soldering or exposed mains connections. Adult guidance is recommended.

How this experiment works

Download class activity guide

Cover illustrations show component types. Functional animations explain principles and are not recorded prototype tests. Follow the supplied connection labels and pinouts.