4 thoughts on “Poseidon

  • 24/08/2024 at 21:24
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    Which power LEDs are best used for a marine aquarium?

    For a marine aquarium, specific power LEDs are required that provide the correct light spectrum to optimally support coral and marine life. Important factors to consider are the color spectrum, light intensity, and the reliability of the LEDs. Here are some important types of power LEDs commonly used for marine aquariums:

    1. Royal Blue (450-460 nm)

    • Function: Stimulates photosynthesis in corals and promotes growth.
    • Why it’s important: Royal Blue LEDs are crucial because many corals depend on blue light for photosynthesis. This light also enhances the fluorescent colors of corals.

    2. Cool White (6500K-10000K)

    • Function: Provides a broad spectrum of light.
    • Why it’s important: Cool White LEDs complement blue light with broader spectral colors and give a natural look to the aquarium.

    3. Violet/UV (380-420 nm)

    • Function: Enhances coral coloration and stimulates fluorescent proteins.
    • Why it’s important: This UV light brings out the vibrant colors of corals, although it’s less crucial for photosynthesis.

    4. Deep Red (660 nm)

    • Function: Supports photosynthesis, especially in deeper or shaded parts of the aquarium.
    • Why it’s important: Corals in deeper areas may rely on red light, though it should be used in controlled amounts to avoid algae blooms.

    5. Cyan (495-520 nm)

    • Function: Enhances the color representation of greenish hues in the aquarium.
    • Why it’s important: Helps fill the gap in the spectrum between blue and red light, providing a more natural appearance to the aquarium.

    6. Warm White (3000-4500K)

    • Function: Provides a more natural, sunny daylight.
    • Why it’s important: This type of light can help balance and simulate natural day and night cycles in the aquarium.

    Brands and Specifications

    Brands like Cree, Philips, and Osram produce high-quality power LEDs that are often recommended for marine aquariums. These LEDs have high light output and are energy efficient. It’s also important to choose LEDs with good heat dissipation, as aquarium lighting is used intensively.

    Additional Tips

    • Full Spectrum: A combination of the above LEDs in one fixture will provide a full spectrum that supports marine life well.
    • Dimmer Function: This allows you to simulate the day and night cycle in the aquarium.
    • Active Cooling: Ensure the lighting is well-cooled, as high temperatures negatively impact the lifespan of the LEDs.

    By combining these elements, you can create a lighting system that is both visually appealing and healthy for the inhabitants of your marine aquarium.

    What are the most important colors?

    The most important colors for a marine aquarium are those that optimally support the photosynthesis process in corals while enhancing their vibrant colors. These are the key colors and why they are crucial:

    1. Royal Blue (450-460 nm)

    • Most important color for coral growth.
    • Why: Royal Blue is the most effective light spectrum for the photosynthesis of zooxanthellae (symbiotic algae in corals). This color helps corals gain energy and promotes growth and health. It also highlights the fluorescent colors of corals.

    2. Cool White (6500K-10000K)

    • Provides a broad spectrum of light.
    • Why: Cool White LEDs complement blue wavelengths with a mix of colors that resemble natural sunlight. This helps the aquarium and corals look more natural.

    3. Violet/UV (380-420 nm)

    • Stimulates fluorescent colors in corals.
    • Why: While UV light is less important for photosynthesis, it helps corals produce fluorescent proteins, making their colors more intense. This light highlights the natural, vibrant colors of corals and other invertebrate sea creatures.

    4. Cyan (495-520 nm)

    • Enhances the natural look of the aquarium.
    • Why: Cyan helps complement the blue and white lights by enhancing green hues, giving the aquarium a more natural appearance. It also helps make the water appear more realistic.

    5. Deep Red (660 nm)

    • Important for overall color representation.
    • Why: Although red light penetrates less deeply into the water, it is crucial to provide a natural light spectrum and support the growth of certain corals in shaded or deeper areas. However, it should be used in controlled amounts to prevent excessive algae growth.

    Summary of the Most Important Colors:

    • Royal Blue (450-460 nm) – Crucial for coral growth and vibrant colors.
    • Cool White (6500K-10000K) – Broad spectrum, supports both growth and color representation.
    • Violet/UV (380-420 nm) – Enhances the fluorescent colors of corals.
    • Cyan (495-520 nm) – Provides natural hues in the aquarium.
    • Deep Red (660 nm) – Adds balance to the spectrum, but use in moderation.

    By using mostly blue, violet, and cool white light, you will achieve the best results for both coral growth and the aesthetics of the aquarium.

    In what ratio should I apply them?

    The ratio of the different power LED colors in a marine aquarium is essential to creating the right light spectrum for both coral health and visual appeal. Here is a recommended ratio based on tested experiences in the reef aquarium hobby:

    Recommended Ratios:

    1. Royal Blue (450-460 nm): 40-50%
    • Why: Royal Blue light is the main component for coral photosynthesis and stimulating vibrant colors. Corals are most dependent on this light spectrum for growth and energy production.
    2. Cool White (6500K-10000K): 20-30%
    • Why: Cool White light complements the blue wavelengths and provides a mix of colors similar to natural sunlight. This helps to naturally illuminate the aquarium and create a realistic appearance.
    3. Violet/UV (380-420 nm): 10-15%
    • Why: Violet and UV light bring out the fluorescent effects in corals, making them glow and intensifying their colors. However, it is less important for photosynthesis, so it should be used in moderation.
    4. Cyan (495-520 nm): 5-10%
    • Why: Cyan helps fill out the light spectrum by enhancing green and blue tones. It helps balance the spectrum and gives the aquarium a more natural look.
    5. Deep Red (660 nm): 5-10%
    • Why: Although red light should be limited to avoid algae blooms, a small amount is needed to provide a full spectrum and support coral growth in shaded or deeper parts of the aquarium.

    Example Ratio for 100% LED Distribution:

    • 40-50% Royal Blue
    • 20-30% Cool White
    • 10-15% Violet/UV
    • 5-10% Cyan
    • 5-10% Deep Red

    Practical Implementation:

    1. More Blue than White: Blue light (especially Royal Blue) should dominate, as corals in natural reef environments receive mostly blue light due to water refraction.
    2. Gradually Balance: Use cool white and other spectrums like UV/violet, red, and cyan in smaller amounts to balance the light spectrum without encouraging algae growth.
    3. Dimmer Function: Make sure your LEDs are dimmable so you can fine-tune the spectrum and experiment with light intensity and timing (e.g., sunrise/sunset effect). This prevents the colors from being too intense or over-illuminating.

    By following these ratios, you create an optimal environment for both coral growth and a visually appealing aquarium.

    How much power is minimally required for an aquarium 100x40x40 (40 cm deep)?

    For a marine aquarium of 100x40x40 cm (160 liters, with a depth of 40 cm), it’s important to have sufficient lighting power to not only cover the surface but also penetrate to the bottom, so corals at all levels of the aquarium can thrive. The required power largely depends on the type of corals you want to keep and the efficiency of the LED lighting.

    General Guidelines for LED Lighting:

    A common rule of thumb for LED lighting in a marine aquarium is 0.5 to 1 watt per liter of water. Since your aquarium is 160 liters, you would need approximately 80 to 160 watts of LED power, depending on the specific needs of your corals.

    More Specific Guidelines:

    1. For Soft Corals (Lower Light Intensity):
    • 0.3-0.5 watts per liter: This translates to a total of 48-80 watts. Soft corals like zoanthids, leather corals, and mushrooms require less light intensity.
    2. For LPS Corals (Low to Medium Light Intensity):
    • 0.5-0.7 watts per liter: This translates to 80-112 watts total. LPS (Large Polyp Stony) corals such as euphyllia and acanthastrea need moderate light intensity.
    3. For SPS Corals (High Light Intensity):
    • 0.7-1 watt per liter: This translates to 112-160 watts total. SPS (Small Polyp Stony) corals such as Acropora and Montipora require strong lighting to grow well and maintain their colors.

    Additional Considerations:

    • Aquarium Depth: With a depth of 40 cm, you don’t need extreme light penetration, like in deeper tanks. However, good light distribution is important to cover the entire water column.
    • Light Distribution and Spread: Ensure even light spread across the aquarium surface. Use LED fixtures with wide light beams or multiple clusters of LEDs to avoid dark spots.

    Summary of Required Power:

    • Minimum power: 80 watts for soft corals.
    • Average power: 100-120 watts for LPS corals.
    • Maximum power: 160 watts for SPS corals and high light intensity.

    With an LED setup between 100 and 160 watts, you’ll have enough power to maintain a well-balanced and well-lit marine aquarium.

    What is the optimal switching frequency when controlling LEDs with PWM?

    The best switching frequency for controlling LED lighting in a marine aquarium with PWM (Pulse Width Modulation) depends on factors such as visual effects, LED performance, and the sensitivity of the electronics. Here are some guidelines for the right frequency:

    General Recommendation:

    • 500 Hz to 2 kHz (500-2000 Hz) is usually ideal for LED lighting in aquariums.
    • This frequency is high enough to prevent flickering visible to the human eye.
    • This range provides a good balance between accurate light control and compatibility with most LED drivers.

    More Specific Frequencies:

    1. 500 Hz to 1 kHz:
    • Why: This is a common frequency for aquarium lighting. It is sufficient to make flickering invisible to the human eye and ensures smooth dimming of the LEDs. This works well for most LED controllers.
    • Application: Suitable for most aquarium setups without very fast dynamic lighting changes.
    2. 1 kHz to 2 kHz:
    • Why: Higher frequencies in this range can help create even smoother transitions when dimming, especially if using sensitive electronics or fast-reacting drivers.
    • Application: Recommended for more advanced systems that may be sensitive to flickering or for sophisticated dimming scenarios like sunrise/sunset simulations.
    3. >2 kHz (2-5 kHz):
    • Why: Frequencies higher than 2 kHz are typically used in special applications where extremely smooth lighting is needed, and there can be absolutely no chance of flicker, such as when filming the aquarium. However, higher frequencies can reduce driver efficiency and lead to more heat generation in some LED drivers.
    • Application: Usually not necessary for standard aquarium lighting unless using sensitive sensors or special video setups.

    Considerations for the Switching Frequency:

    • Visual Flicker: Frequencies below 100 Hz can cause visible flicker, which can stress fish and corals and be noticeable to the human eye.
    • Electromagnetic Interference (EMI): Higher switching frequencies can generate more EMI, potentially causing interference with other electronic devices, especially in technology-heavy aquariums.
    • Driver Efficiency: Very high PWM frequencies (>2 kHz) can reduce LED driver efficiency and lead to increased heat production.

    Conclusion:

    A PWM switching frequency between 500 Hz and 2 kHz is generally the best compromise for LED lighting in marine aquariums. This prevents visible flicker, ensures smooth dimming, and doesn’t overburden the electronics. For most aquarium applications, around 1 kHz is an excellent choice.

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  • 24/08/2024 at 21:33
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    Example PWM code for Esp32

    // Define the PWM Channel, Frequency, and Resolution
    const int pwmChannel = 0; // PWM channel (0 to 15)
    const int pwmFrequency = 5000; // Frequency in Hz (can be from 1 Hz to 40 MHz)
    const int pwmResolution = 8; // Resolution in bits (1 to 16 bits)
    const int pwmPin = 5; // The pin you want to output PWM on

    void setup() {
    // Configure PWM functionalitites
    ledcSetup(pwmChannel, pwmFrequency, pwmResolution);

    // Attach the pin to the PWM channel
    ledcAttachPin(pwmPin, pwmChannel);
    }

    void loop() {
    // Create a sawtooth wave by sweeping the duty cycle from 0 to 255
    for (int dutyCycle = 0; dutyCycle <= 255; dutyCycle++) { ledcWrite(pwmChannel, dutyCycle); // Write the duty cycle delay(10); // Wait for 10ms } }

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  • 25/08/2024 at 09:40
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    Q: LEDs glued to an aluminium plate?

    Yes, even when the 3W power LED is attached to the aluminum plate with **Loctite EA 9497**, the heat can still be dissipated effectively. Loctite EA 9497 is a thermally conductive two-component epoxy adhesive with a thermal conductivity of **1.7 W/m·K**, which is sufficient for this application.

    Here’s why this works:

    1. **Thermal conductivity of Loctite EA 9497**: Although the adhesive has a lower thermal conductivity than aluminum, **1.7 W/m·K** is still good enough for transferring heat from the LED to the aluminum plate. This means the heat from the LED is sufficiently transferred to the plate, which can then spread it further.

    2. **Aluminum plate**: As discussed earlier, the aluminum plate, with a thermal conductivity of approximately **205-235 W/m·K**, has excellent properties to quickly and efficiently spread the heat from the adhesive and the LED to the surrounding air.

    3. **Limited heat production**: A 3W LED produces relatively little heat (about 2-2.4W needs to be dissipated), and with an aluminum plate as a heatsink, combined with a thermally conductive adhesive like Loctite EA 9497, this amount of heat can be effectively dissipated.

    ### Conclusion:
    The combination of a **3W LED**, **Loctite EA 9497**, and a **2 mm thick aluminum plate** will likely be sufficient to dissipate heat effectively, as long as the plate has enough surface area and reasonable ventilation. This should keep the LED cool enough to operate efficiently and ensure a long lifespan.

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