Nightlight Circuit Design
A nightlight circuit using a light-dependent resistor as the sensor, a 2N2222 transistor as the switch, and two potentiometers for adjustment.
Key Features
- Uses the 10K Potentiometer
- Uses the LDR Photoresistor
Key Benefits
- Free, open lessons. The Moving Rainbow textbook has the kit page, wiring, and MicroPython code.
- Classroom friendly. Built on a solderless breadboard or no-solder connectors.
- Real-world data. Students read sensors and turn measurements into decisions.
- Budget. About $4–$6 (estimate: breadboard $2, photoresistor and 2N2222 transistor under $1 together, two potentiometers about $1, an LED and resistors).
Parts
| 10K Potentiometer | Input knob |
| LDR Photoresistor | Sensor |
| 830-Point Breadboard ($1.10) | Breadboard |
Microcontroller listed first. Prices shown only where known; see the source book for quantities, wiring, and current prices.
About this kit: From the Moving Rainbow collection.
Source: Moving Rainbow