This circuit shows you how to build your own wireless headphones!
Instead of a wire connecting them to your device, they use invisible light signals infrared or IR to transmit the sound.
This lets you move around freely while listening and you can even control them from a distance like turning up the volume or changing songs.
What is a Infrared Headphones Receiver Circuit:
An Infrared IR Headphones Receiver Circuit is an electronic circuit designed to receive audio signals transmitted wirelessly via infrared light.
Infrared headphones are a type of wireless headphones that use infrared technology to transmit audio signals from a source like a TV or audio system to the headphones.
The receiver circuit is a crucial component in the headphones that captures the transmitted signals and converts them back into audible sounds.
Circuit Working:
Parts List:
| Category | Description | Quantity | Notes |
|---|---|---|---|
| Resistors | 470k | 1 | 1/4 watt |
| 820k | 1 | 1/4 watt | |
| 560Ω | 1 | 1/4 watt | |
| Preset | 100k | 1 | 1/4 watt |
| Capacitors | Ceramic 10nF | 1 | |
| Electrolytic | 47μF 16V | 2 | |
| 22μF 16V | 2 | ||
| Semiconductors | Transistor BS170 | 1 | |
| IR receiver LED BP104 | 1 | ||
| Others | Headphone | 1 | |
| Battery 9V | 1 |
Utilize the infrared headphones receiver in conjunction with the IR headphones transmitter.
Employ headphones with a impedance of 600Ω.
The BPW41N and BP104 feature a filter designed for visible light centered at 950nm at 25°C.
Under standard light conditions and at a distance of 3 to 4 meters audio distortion ranged from 1% to 2% which is acceptable considering the simplicity of the IR headphones receiver schematic.
How to Build:
Building an infrared IR headphones receiver involves several steps.
Identify Components:
- Choose the appropriate infrared photodiode based on your specifications.
- Verify the impedance of the headphones and ensure compatibility with the receiver.
Design the Circuit:
- Design a basic circuit that includes the photodiode amplifier if needed, and impedance matching components.
- Incorporate a filter to block visible light and focus on the infrared spectrum.
Assemble the Circuit:
- Build the circuit on a PCB or a breadboard.
- Connect the components according to the circuit diagram.
Connect the Infrared Headphones Transmitter:
- Establish a connection between the IR headphones transmitter and the receiver.
- Ensure proper alignment and line of sight for effective signal transmission.
- Connect a suitable power source to the circuit.
- Verify that the power supply meets the requirements of the components used.
- Test the receiver at a reasonable distance 3 to 4 meters under normal light conditions.
- Measure audio distortion using appropriate tools.
Adjustments:
- Fine tune the circuit as needed to optimize performance.
- Adjust amplifier gain or other parameters for desired audio quality.
Final Testing:
- Conduct thorough testing in various conditions to ensure the reliability of the IR headphones receiver.
Documentation:
- Document the final circuit design, connections and any adjustments made for future reference.
What is a Infrared Headphones Transmitter Circuit:
An Infrared Headphones Transmitter Circuit is an electronic circuit designed to transmit audio signals wirelessly to infrared IR headphones.
The transmitter circuit is a crucial component in an infrared wireless headphone system, enabling the wireless communication of audio signals from a source to the headphones.
Circuit Working:
Parts list:
| Category | Description | Quantity | Notes |
|---|---|---|---|
| Resistors | 100k | 1 | 1/4 watt |
| 82k | 1 | 1/4 watt | |
| 6.8Ω | 1 | 1/4 watt | |
| Preset | 100k | 1 | |
| Capacitors | Ceramic 100nF | 1 | |
| Electrolytic | 220μF 16V | 1 | |
| Semiconductors | Transistor BC547 | 2 | |
| Transistor BS170 | 2 | ||
| IR transmitter LED LD271 | 3 | ||
| Others | Battery 9V | 1 |
The transmitter facilitates an optical connection infrared for headphones.
T1 current polarizes three infrared LEDs IR, and P1 is utilized to fine tune the current level.
The current consumption of this infrared transmitter for headphones is approximately 60mA at 9V.
To prevent current reactions through the LEDs, it is advisable to keep the adapter ground separate from the audio signal ground.
The optical link is relatively directional and can be enhanced by situating the LEDs at different angles and incorporating reflectors behind them.
For optimal performance the recommended input audio level ranges from 100 to 200mV providing coverage of 1.2 to 2.4 meters for this infrared transmitter.
We offer the schematic for the infrared receiver for this specific infrared headphone transmitter on our website.
Formula:
The voltage gain (Av) of a Field Effect Transistor FET amplifier may be computed using the following generic formula:
Av = −gm * RL
where,
- gm is the transconductance of the FET, which is given by gm = 2ID / VGS − Vth
- ID is the drain current of the FET.
- VGS is the gate source voltage of the FET.
- Vth is the threshold voltage of the FET.
- RL is the load resistance connected at the drain of the FET.
Justification:
Transconductance gm: The amount that the FETs output current varies in response to variations in the input voltage (gate source voltage) is indicated by this parameter.
It is a measurement of the FET amplifiers gain.
Load Resistance RL: This is the external resistor that is linked to the FET amplifiers output (drain).
It establishes the amplifiers voltage gain.
How to Build:
Building an Infrared Headphones Transmitter involves several steps and it requires a good understanding of electronics.
Identify Components:
- Choose suitable infrared LEDs a transistor for current polarization T1, and a preset P1 for current adjustment.
- Select resistors, capacitors and other electronic components based on the circuit design.
Design the Circuit:
- Create a circuit diagram that includes the infrared LEDs current polarization components, current adjustment components and audio input components.
- Decide on the placement of reflectors if you choose to incorporate them.
Assemble the Circuit:
- Build the circuit on a PCB or a breadboard.
- Connect the components according to the circuit diagram.
Connect the Audio Input:
- Connect the audio input from your source device to the transmitter circuit.
Power Supply:
- Connect a suitable power source battery or external power supply to the circuit.
Adjustments:
- Use the preset P1 to adjust the current level through the LEDs.
- Fine tune the circuit for optimal performance.
Testing:
- Test the transmitter with an infrared receiver and headphones.
- Check the range and audio quality of the transmitted signal.
Conclusion:
The infrared wireless headphone circuit allows users to enjoy audio content wirelessly while providing the convenience of remote control functionality.
It finds applications in scenarios where freedom of movement and the ability to control audio playback remotely are desirable features.
The circuit design can vary based on the specific requirements and features desired by the designer or user.