Simple Automatic Doorbell Light Circuit is like small help friend for our door
When someone presses doorbell light turn ON by itself near button.
It help us to see button easily and specially in night or dark time.
So we can open door fast and can be safe for visitor.
Circuit Working:
Parts List:
| Category | Component | Quantity |
|---|---|---|
| Resistors (All resistors are 1/4 watt unless specified) | 2.2k 1W | 1 |
| 10k | 1 | |
| 100k | 1 | |
| 1k | 1 | |
| Capacitors | PPC 180nF 400V | 1 |
| Electrolytic 100µF 16V | 1 | |
| Semiconductors | IC 4N35 | 1 |
| IC 555 | 1 | |
| LEDs white 5mm 20mA | 1 | |
| Doorbell 230V | 1 |
This circuit uses one 6V battery doorbell light which we can use with normal AC 230V doorbell together.
When someone presses the doorbell the bell ring sounds like normal and at the same time AC power goes to circuit through opto coupler IC1.
When IC1 work it start monostable circuit using 555 timer IC2.
Then one bright white LED D1 turn ON for short time.
This is very helpful at night as it gives light so we can find room switch or outside light easy.
We can change how long LED stays ON/OFF by changing C2 value.
This circuit is safe as IC1 keep it separate from dangerous AC power.
But be careful do not touch front part of circuit it is connected with AC directly.
Better to put this circuit inside strong ABS box to stay safe.
Formula:
When trigger signal comes monostable multivibrator which is also called one shot pulse maker gives one output pulse only.
In auto doorbell light circuit when someone presses the doorbell LED turns ON for some time.
We can control how long LED stays ON using this formula for pulse time:
Pulse Time T = 1.1 × R × C
where:
- T is pulse time in seconds (s)
- R is resistor in ohms Ω
- C is capacitor in farads F
This formula help us to design simple doorbell light using 555 timer in monostable mode.
Just change R and C to get time we want to turn light ON.
How to Build:
To build a Simple Automatic Doorbell Light Circuit follow the below mentioned assembling steps:
Get the parts:
- Gather all parts we see in the circuit diagram.
Make the circuit:
- Put doorbell switch in parallel with AC 230V doorbell.
- Connect opto-coupler IC1 to doorbell switch and AC power.
- Then connect 555 IC2 and bright white LED D1 to output of IC1.
Build the circuit:
- Put all parts on PCB board and solder them same like circuit diagram.
Try the circuit:
- Put 6V battery in holder and press the doorbell switch.
- LED should turn ON for short time.
Change LED time:
- If LED stay ON too short or too long then change capacitor C2 value.
Cover the circuit:
- Put whole circuit inside strong ABS box to protect from touching or outside damage.
Fix near doorbell:
- Place this doorbell light near the doorbell and be sure it is fixed well and safe.
Note:
- Be careful working with electricity can be dangerous.
- If anyone do not know electronics well ask help from someone who know or call the professional.
Conclusion:
Simple Automatic Doorbell Light Circuit is very useful and easy for any doorbell system as it help us to see better especially when light is low.
When someone presses the doorbell the light turn ON by itself near the button and this make it easy for people inside to find the switch fast.
This circuit is simple and works good.
It is nice to improve for any home or building door area.