Backyard Lamp Circuit using IC CD4060

This Backyard Lamp Circuit using IC CD4060 works like smart switch for outside light.

It uses one special sensor, LDR to know if it is day or night.

When night comes circuit turn ON the backyard lamp by itself.

Then morning comes with light again it turns OFF the lamp.

It do this with a small chip CD 4060 which work like timer.

Circuit Working:

Parts List:

This backyard lamp circuit turn ON the light at 10 pm by itself and keep it on whole night.

It help keep away night animals and stop thief.

It uses LDR sensor to work like light switch.

LDR know if it is dark or bright.

Circuit has no transformer.

It uses special power and timer setup.

Parts like C1, D1 to D4 and C2 make the power supply.

C1 is AC capacitor it reduces big AC voltage to a safe level.

Diodes D1 to D4 change AC to DC and C2 makes DC smooth.

R1 is for safety it removes charge from C1 when OFF and R2 stops big current at start.

LDR tell IC1 to start at sunset.

When at dark LDR have high resistance to about 10 mega ohm.

When bright its resistance is low like 100 ohm or less.

IC CD4060 is timer chip it have built-in counter and oscillator.

Day time LDR is with low resistance to keep pin 12 of IC1 high so that the chip does not work.

Night time LDR resistance connects to pin 12 which goes low and so the chip start working.

C3, R4 and R5 make the timer.

Red LED blink when IC1 start.

With current values pin 1 become high after 4 hours around 10 pm.

Then Triac turns ON then the lights also turns ON.

At same time D5 diode block the timer to stop IC1 counting more.

IC1 stay in ON mode till morning.

In morning LDR see light again and start to reset IC1.

Then it wait for sunset again.

Put whole circuit is enclosed in a safe box but let LDR face the sun.

Keep lamp far so it does not affect LDR light sensing.

VR help to set light level where LDR turn circuit ON /OFF

LDR in black tube which makes VR adjust easily.

Warning:

This circuit connect directly to high voltage without any isolation.

Never test when the plug is in.

Only touch VR with tool may be with screwdriver with cover.

Do not touch parts when power is ON.

Note:

Do not use CFL or tube light this is because triac does not gives full power and can break those lights.

Formulas:

Using IC 4060 to make backyard light circuit means we can build timer.

This timer turn the lamp ON and OFF after some time as the time is set by IC 4060.

How long IC 4060 wait (timer delay) depend on resistor and capacitor we connect.

In this circuit R4 + R5 resistors and C3 capacitor control the timing.

We have used this formula to find the time (T):

T = 2.3 × R × C

here,

R = R4 + R5

C = C3

So the timing becomes:

T = 2.3 × (R4 + R5) × C3

where,

• R4 and R5 connects to oscillator pin of IC 4060 and then they set resistance.
• C3 connects to same oscillator pin to set the capacitance.

Note:

This idea and simple circuit are just starting point to build IC 4060 based timer for backyard lamp.

We can change R4, R5 and C3 values to get different time delay so that light turns ON when one wants.

How to Build:

To build a Backyard Lamp Circuit using IC CD4060 below mentioned are the steps:

Be Safe First:

• Before starting be sure we know how to work with high voltage (mains power).
• Take all safety steps and work in open place with fresh air.
• Use tools with insulation with no metal touching.

Power Part:

• Connect C1 in series with mains to lower voltage.
• Use D1 to D4 to make full wave rectifier which changes AC to DC.
• C2 smooth the DC power.
• R1 is bleeder as it remove charge from C1 when circuit is OFF.
• R2 stop big current when is power ON.

Timer Part:

• LDR tell IC1 CD4060 to start at sunset.
• CD4060 is timer chip with counter and oscillator built inside.
• When it get dark the LDR resistance go high as it pull down pin 12 of IC1.
• Then IC1 start timer using C3, R4 and R5.
• Red LED blink that mean IC1 is running.
• With set values of C3, R4, R5 pin 1 go high after 4 hours we can adjust time with VR.

Lamp Control:

• When pin 1 goes high Triac turn ON the lamp.
• D5 also turn ON and stops IC1 from counting more.
• IC1 stay ON whole night and pin 1 stays high.
• In morning LDR see sunlight and IC1 reset by lamp turning OFF.
• Then wait for sunset again.

Box and Setup:

• Put whole circuit in safe box for shockproof.
• Keep LDR outside to see light.
• Put unit where sun can reach it.
• Keep lamp far from LDR so lamp light does not get confuse with it.
• Use VR to set how dark it should be before turning ON.
• Putting LDR inside black tube helps one to adjust it better.

Important Note:

• This circuit uses direct mains power which is dangerous if not handled right.
• Better to ask expert or someone with experience before one try to build it.

Conclusion:

Backyard Lamp Circuit using IC CD4060 is easy and useful.

It turn ON the light by itself at night and is good for keeping away night animals and stopping theft.

But be careful this circuit uses high voltage (mains power) which can be dangerous.

So always take care when making or testing it.

References:

Datasheet IC CD4060