Automatic Dimness Controlled Lighting System
Using this automatic control system, you may program the tube lights to turn on automatically when night falls and turn off when the sun comes up. A lighting system that is controlled aut…
Know the mission before touching a wire.
Understand what you are making, prepare the right tools, and make the workbench safe.
Project details
Automatic Dimness Controlled Lighting System is a electronics project. Using this automatic control system, you may program the tube lights to turn on automatically when night falls and turn off when the sun comes up. A lighting system that is controlled aut…
- Source pages
- 272-273
- Named parts
- 2
- Build goal
- Working, tested prototype
Tools you need
- Digital multimeter
- Wire stripper and side cutters
- Soldering iron with a fine tip
- Current-limited bench supply
Use eye protection, good lighting, and a clean insulated surface throughout the build.
Safety precautions
- Disconnect every power source before changing a connection.
- Check component polarity, pinout, and supply voltage twice.
- Use a current limit for the first power-up.
- Keep liquids, loose metal, and uninsulated wires away from the bench.
Gather, identify, and understand every part.
Use the standardized inventory, then open What's this? to learn each part's role, advantages, limitations, handling, and specifications.
What's this?Image, role, pros, cons, handling & specifications
MODULE LEARNING VIEWLDR
A sensor converts a physical condition into an electrical signal the circuit can measure.
What it does hereIt provides project input as an analogue, digital, resistive, frequency, or calibrated signal.
Buy / compare this part ↗Advantages
- Adds real-world awareness
- Can usually be tested independently
- Often supports calibration
Limitations
- Readings can drift
- Placement affects results
- Some sensors need warm-up or calibration
Handling
- Protect the sensing surface
- Observe supply voltage and polarity
- Keep signal leads away from noisy power wiring
Specifications to verify
- Use the exact model, value, package, and rating listed for LDR; similar-looking parts are not always interchangeable.
- Confirm supply range, output type, measurement range, accuracy, response time, and pin order.
What's this?Image, role, pros, cons, handling & specifications
SEMICONDUCTOR LEARNING VIEWBT136 - specified part
A semiconductor stage performs switching, amplification, regulation, rectification, or logic.
What it does hereIt controls current or signal flow at a defined point in the circuit.
Buy / compare this part ↗Advantages
- Fast and efficient
- Compact
- Can control larger loads from smaller signals
Limitations
- Pin order varies
- Sensitive to overvoltage and reverse polarity
- May need cooling or bias components
Handling
- Verify the datasheet pinout
- Avoid static and soldering heat
- Check notch, stripe, or flat-face orientation
Specifications to verify
- Use the exact model, value, package, and rating listed for BT136 - specified part; similar-looking parts are not always interchangeable.
- Confirm pinout, maximum voltage/current, dissipation, gain or forward voltage, and package.
Connect one verified path at a time.
Explore the named components and standardized signal flow, then use Source Check to verify exact physical pins, values, and topology before applying power.
Trace this circuit.
Automatic Dimness Controlled Lighting System: interactive parts, standardized terminals, responsive anchored wires, student explanations, and the original circuit reference in one shared system.
Trace before wiring
Follow power, ground, inputs, processing, and outputs in that order. Never guess a pin from package shape alone.
Connect with power off
Make short, labelled connections and share a common ground only where the schematic requires it.
Inspect every joint
Check continuity, polarity, adjacent shorts, and loose connections before the first power-up.
Open all source diagrams and build views 1 visuals
Confirm the hardware-only control path.
This project does not include firmware in the source. The circuit itself provides the required behaviour.
How to connect
- Match every controller label to the circuit view and source pin map.
- Join grounds before signal wires when separate low-voltage supplies are used.
- Keep motors, relays, pumps, and other loads on a suitable driver and external supply.
Common mistakes
Reversed VCC/GND, board-label versus GPIO-number confusion, missing common ground, and charge-only USB cables.
Troubleshoot
Disconnect loads, continuity-test one path at a time, then test with a current limit.
Software preparation
No IDE, board package, library, or firmware upload is required for this project.
If you add a programmable controller as an extension, document its pin map separately.
How to upload code
The original design is implemented entirely in hardware, so proceed after verifying the circuit and supply.
Assemble, deploy, test, and troubleshoot.
Use the complete source notes in build order, then pass the final checks before calling the project finished.
Build in functional stages
- Power and regulation
- Controller or processing stage
- Inputs and sensors
- Outputs and loads
- Enclosure and strain relief
Power up safely
- Inspect unpowered continuity first
- Apply the lowest safe current limit
- Measure supply rails before signals
- Add one load at a time
- Record expected and actual results
Work from simple to complex
- Confirm power, ground, polarity, and orientation
- Compare each pin with the source
- Test inputs separately from outputs
- Replace only one variable at a time
- Power off before every correction
Follow the documented instructions.
These notes come from this project's source and remain in their original order.
Project overview
Project build noteUsing this automatic control system, you may program the tube lights to turn on automatically when night falls and turn off when the sun comes up. A lighting system that is controlled automatically by the presence or absence of darkness will cause a light source, such as a bulb or tubelight, to glow whenever darkness is detected. The circuit is powered by 5V that has been regulated, and it consists of a triac BT136, a NOT gate 7404, and a light-dependent resistor (LDR).
Figure: Circuit of automatic darkness-controlled lighting system
Project build noteThe operation of the circuit is really straightforward. The low resistance of LDR1 causes pin 1 of gate N1 to be low and for pin 2 of its output to be high when it is daytime. This high output is connected to the third input pin of the gate N2. As a direct consequence of this, the output of gate N2 will now be low. Since triac BT136 (triac 1) does not receive any gate signal, it behaves as an open circuit; hence, the light bulb does not glow. When it is nighttime, the high resistance of LDR1 causes pin 1 of gate N1 to become high, while the output pin 2 of gate N1 becomes low. This low output is connected to the third input pin of the gate N2. As a consequence of this, the output of gate N2 becomes high, which is then applied to the gate of triac BT136 (triac 1), where it functions as a short circuit, causing the bulb to begin illuminating. Construct the circuit on a printed circuit board (PCB) designed for general use, then store it in an appropriate location. Maintain LDR1 in a position where it receives an adequate amount of light during the day. You can also use this circuit to control the lights at the street intersection.
You built Automatic Dimness Controlled Lighting System.
You followed the full workflow from understanding the mission to testing the finished project. That is a real engineering achievement - well done.
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