Wireless LED Light Circuit

Nowadays there are wireless charging inside many things like phone and even big medical machines.

In this article we will show how to make Wireless LED Light Circuit which light using one small chip called IC 555.

No wire needed the LED will light up to show how wireless charging works.

What is a Wireless LED Light Circuit:

A wireless LED light circuit is an electric setup that controls LED light without cable or any physical connection.

This wireless system uses many tech like Bluetooth, Wi-Fi, infrared and radio frequency (RF).

Because of this circuit the LED lights the work easily with remote so it is good for lighting system and very flexible for use.

Circuit Diagram:

Parts List:

Transmitter Circuit Working:

555 IC is set as astable multivibrator to make nonstop 20KHz square pulse.

Resistor R1, R2 and capacitor C1 decide how long charging and discharging takes.

C1 charge through R1 and discharge through R2 again and again and this make loop of oscillation.

Inside 555 IC the flip-flop changes state when C1 voltage goes up to 2/3 of power supply VCC.

Then C1 send power out through R2 and discharges pin 7 which become low.

When C1 voltage drop to 1/3 of VCC the flip-flop changes again and pin 7 goes high.

Because of this it keeps happening and pin 3 of 555 IC give nonstop square pulse.

This pulse goes to gate of IRF540 N Channel MOSFET.

When pulse is high MOSFET turns ON like switch and when pulse is low it turn OFF.

Coil L1 connect to MOSFET drain so coil turns ON and OFF again and again.

Because of this magnetic field around coil L1 starts to oscillate strong.

Receiver Circuit Working:

To catch the changing magnetic field receiver coil L2 is put close to transmitter coil L1.

With help of Faradays law the coil L2 makes current when magnetic field changes near it.

Diode D1 connect to one side of coil L2 and work likes rectifier.

It changes the AC signal from coil into DC signal with only one direction.

After that signal go to voltage doubler circuit which makes voltage bigger.

This bigger voltage is enough to turn ON twelve LEDs.

Because of this voltage difference is made and LEDs light up in the circuit.

Formulas and Calculations:

We can use these formulas to find values for astable 555 IC in wireless LED light circuit:

Flashing Frequency Formula:

Frequency = 1 / (1.1 × R1 × C1)

where:

• Frequency (f) is in hertz Hz
• R1 is resistor in ohms Ω which is 1k
• C1 is capacitor in farads F which is 3.3nF = 3.3 × 10⁻⁹ F

Calculation:

f = 1 / (1.1 × 1000 × 3.3 × 10⁻⁹)

f = 294.1 Hz

So flashing frequency of circuit is near 294.1 Hz.

That mean LED flash about 294 times in 1 second.

Duty Cycle:

Duty cycle is how much percent of time LED stay ON in full cycle (ON + OFF).

Formula:

Duty Cycle = R2 / (R1 + R2) × 100%

where:

• R1 is 1kΩ
• R2 is 10kΩ

Calculation:

Duty Cycle = 10k / (1k + 10k) × 100%

Duty Cycle = 90.9%

So LED is ON about 90.9% of time and OFF only 9.1%.

Summary:

With these parts circuit give about 294.1 Hz flashing and 90.9% duty cycle.

That means LED blink very fast and stay ON most of the time.re ON they will flash for a greater duration than when they are OFF.

Remember:

These calculations numbers are for 555 IC working is perfect and all parts have exact value.

But in actual circuit small changes can happen because parts are not always perfect and other small problems.

How to Build:

To build a Wireless LED Light Circuit following steps should be followed:

• Put IC 555 on the PCB.
• Connect VCC pin and reset pin to positive power on PCB.
• Put resistor R1 between discharge pin 7 and positive power.
• Put resistor R2 between discharge pin and the two pins (threshold and trigger) that are joined together.
• Put capacitor C1 between threshold pin and ground pin.
• Join trigger pin and threshold pin together.
• Connect resistor R2 again between the joined trigger threshold pins and discharge pin.
• Connect output pin 3 of IC 555 to gate pin of IRF540 MOSFET.
• Connect drain pin of MOSFET to transmitter coil L1.
• Connect source pin to ground on PCB.
• Connect power supply:
• Positive to VCC pin and negative to ground pin.

Transmitter Coil L1 Winding:

• Use 18 SWG insulated copper wire
• Ferrite core is optional
• Wind 25 turns of wire
• Use round object like pipe to keep coil shape same
• Connect one end of coil to drain pin of IRF540 MOSFET
• If we want better working use ferrite core
• Wind wire around ferrite core for better power transfer

Receiver Coil L2 Winding:

• Use 22 SWG insulated copper wire
• Wind 100 turns of wire
• Wind slowly and neatly with no overlapping
• Connect one end of coil to anode of diode D1 and other end connect to ground or reference point in circuit

Extra Note:

Ferrite core for receiver coil is also optional.

Like transmitter coil we can use ferrite core in receiver coil to make it work better.

Just wind copper wire around ferrite core.

Safety:

Be careful do not let wire turns touch each other and keep coil winding clean and strong.

How much power coil can send depends on number of turns and core material we use.

We can change the circuit later if needed based on our testing and project needs.

Conclusion:

With this Wireless LED Light Circuit after making both Transmitter and Receiver circuits we can see LEDs glow with wireless power

Always follow safety rules when working with circuit.

References:

Wireless power transfer