Automatic Night Lighting Control

Question

Problem: Automatic Night Lighting Control. Solve this hands-on electronics task on EWskills.

Accepted Answer

A street lighting system must activate when the light sensor signal is low. Since standard NOT gates are not available, the circuit is implemented using a NAND gate configured as an inverter.

To understand how this line is evaluated, we examine the truth table for a NAND gate where inputs A and B are tied together (A = B):

Input (A and B tied)	NAND Output
0	1
1	0

Calculation breakdown:

When the Sensor is 0 (Dark): Both inputs to the NAND gate are 0. The output of a NAND gate is 1 when any input is 0; therefore, the Street Light Output is 1.
When the Sensor is 1 (Day): Both inputs to the NAND gate are 1. Since both inputs are high, the NAND gate outputs 0, turning the light off.

Circuit Implementation:

Inversion Gate: Connect the Ambient Light Sensor to both inputs of a NAND gate.
Connect: Map the output of the NAND gate to the Street Light Output probe, ensuring the street light activates automatically when it is dark.

3. Automatic Night Lighting Control