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ProjectGuideLED Project Design Guide THIS PAGE IS A WORK IN PROGRESS Link to the Webpage which is updated and formatted: http://www.nledshop.com/projectguide/ A basic tutorial on building your own LED lights, LED art project, pixel matrix, pixel mask, anything with LEDs or pixels. This is not meant to be a one-stop guide, but a source for basic questions and terminology. All the information provided are educated opinions, please do additional research using other sources. THIS IS A WORK IN PROGRESS. Please forgive grammar and other mistakes. Please submit questions, comments to improve the content. Or submit links to other relevant content that should be included. This is going to be broken into multiple pages with added pictures someday. NLED has no affiliation in anyway with any of the external websites that are linked from this guide. Controllers: A controller comes in different types, the controller needs to be compatible with the LEDs or pixels that are being used. A controller receives data control(such as DMX) or local stand-alone color sequences and converts the values to an output for the LEDs. Output, Constant Voltage: Most common type, does not regulate current and provides a consistent voltage, usually the output is PWM controlled to vary the channel intensity. Used to control LEDs such as standard 12 volt LED strip or modules. Output, Constant Current: A less common type, regulates the output current to a constant selectable value, voltage is consistent but can be higher than the LED's rated voltage. Used to control high-wattage LEDs like 350mA or 700mA types, or smaller LEDs such as 5mm or 10mm types. Typically these controllers only work with a single current range. Output, Pixel Controller: Becoming more common, these types of controllers are used to talk to smart/addressable pixels, such as WS2812, WS2801, APA102. These controllers do not control the LEDs directly, but rather produce a data signal that is received by the pixels and decoded into light intensity for the colored LEDs within the pixel. Input, DMX-512, ArtNet: The most common control protocols that a software application will output. Packets are limited to 512 channels which is 170 RGB LEDs or 128 RGBW LEDs. Strands controlled with DMX/Artnet can not be longer than that unless the controller features universe merging. Input, Serial, USB, Bluetooth, WiFi: A different way to transmit data to controllers. None of those are protocols necessarily, but are ways to interface from the transmitting PC(or other device) and the controller. WiFi could use protocols such as the NLED serial or even DMX/Artnet. Input, Stand-Alone: Controller stores color sequences locally, either in memory or on an SD card. The user must load the sequences prior to usage. NLED products can trigger and control the stand-alone sequences through commands and software. Pixel Controller: Output Packet Rate: Also referred to as FPS(frames per second) which is how often the pixels are updated with new data. The pixels can not be updated with new data if the new data has not yet been received or transmitted. So the actual pixel packet rate is tied to the input packet rate. The maximum packet rate is limited by the pixel chipset. Asynchronous chipsets can not update as fast and commonly have a limit of 30 FPS with 1024 pixels at best. Synchronous chipsets can update faster and the upper limits is set by the controller's pixel output clock rate. As an example, a WS2801 at 2.6Mhz(NLED default) clock output, with 1000 RGB pixels takes 9.2mS to send the packet to the pixels. 1000 RGB pixels of WS2812 at 800Khz takes 30mS to transmit to the pixels. Input Packet Rate: DMX is typically 24 to 44 FPS, depending on software or console settings. Software applications will have internal values to use as the packet rate, but is also limited by how long it takes to send the data out. Using other data sources such as serial, the input packet rate can be adjusted depending on baud rate of the serial data. To transmit data for 1000 RGB pixels at 1 mega baud(1,000,000) it takes 10uS per byte. There are 3000 bytes(one per channel) that are transmitted. Which takes 30mS to transmit the 3000 channels/bytes from PC(or other device) to the controller. Then that data is converted and sent from the controller to the pixels, which takes additional time. Reception of new data and transmission of the pixel data happens at the same time. There is a latency between what the PC sends and what is updated to the pixels, but there are numerous other aspects(such as drivers, USB enumeration, etc) that can delay the packet update even more. 100mS latency can be reasonably expected. Stand-Alone Packet Rate: For NLED pixel controllers running Aurora stand-alone color seqeunes can perform extremely fast packet rates. Commonly that is 50 FPS, which creates very smooth color fades and transitions. Smart or Addressable Pixels: The most important part of a LED project, the LED didoes. Smart or Addressable Pixels: The most recent development in LEDs, these usually contain integrated RGB or RGBW LED diodes with an integrated driver. The pixels are not powered by the controller but rather receive a digital data signal that the pixel uses to output variable light intensities. Multiple pixels can be (daisy) chained together one after the other to create strands of pixels. Each pixel in the strand can be individually controlled through the data protocol. Pixels come in different chipsets, each chipset requires a different data protocol and has different features and capabilities. Look online for additional information. And visit the LED Pixel Chipsets page for supported chipsets supported by NLED. Pixel Chipsets: Pixels are built around what is called a 'chipset', that is the integrated circuit that does the protocol decoding, current regulation, and PWM output. They are available in multiple form factors, capabilities, colors(RGB, RGB-WW, RGB-CW) all with different with pros and cons. https://www.nledshop.com/pixelchipsets/ https://github.com/FastLED/FastLED/wiki/Chipset-reference Chipset Protocol: Each chipset uses a different protocol, which can be considered similar to a spoken language. The controller must 'speak' the same language as the chipset understands. Some protocols are similar to others and can be used interchangeably, and some protocols are standardized and is supported by multiple chipsets. Chipset PWM: An important, if not most important characteristic of a chipset. PWM frequency and PWM resolution. Described on the NLED chipsets webpage and on external links. https://www.arduino.cc/en/Tutorial/SecretsOfArduinoPWM https://en.wikipedia.org/wiki/Pulse-width_modulation Chipset, Asynchronous vs Synchronous: Describes how many 'wires' it takes to control a pixel. Synchronous uses protocols similar to SPI that uses a wire for clock and data. These are typically much faster to transmit data to and easier to write the code routines. Asynchronous use a single wire(DAT) to send the data, it is time based and has to be transmitted with the exact timings. Can be very difficult to build and transmit the required data, but is easy to wire and typically the cheapest option. 5050 Pixel: The most popular chipset of WS2812 has all the electronics integrated into a single '5050' RGB LED. The '5050' form factor is 5mm x 5mm and is an industry standard size, and there are more sizes being sold, such as the APA102-2020 which is 2mm x 2mm. Other chipsets such as the APA102 also are an integrated 5050, but has more pins as it is synchronous. Pixel Module: Chipsets like the WS2811, may be on a strip with 5050 LEDs, but can be considered a module, as the WS2811 typically will control groups of 3 LEDs(per section), each LED is not individually controllable. Some pixel modules are separate modules with 3 or more LEDs per module, each module is individually controllable, but not per LED. They are connected together in a strand with ribbon cable between them. Common example are WS2801 or WS2811 based 12 volt modules with 3x or 6x 5050 RGB LEDs per module. https://www.doityourselfchristmas.com/wiki/index.php?title=Different_Styles_of_Pixels How to ID a pixel chipset: 1. Look for an integrated IC, black plastic with multiple pins. Read the label, and count the wires. 3 Wires: WS2811. 4 Wires: WS2801, LPD8806, or a few others. 2. If it is a 5050 LED, count the pins, if it has 4 pins: It could be any number of types, such as: WS2812. Look at the LED diode, if it has a white or yellow stripe across half of it, it could be a RGBW pixel such as the SK6812. 3. If it is a 5050 pixel with 6 pins, it could be: APA102, APA107 Strip LEDs, 12 volt or 24 volt: The most important part of a LED project, the LED didoes. 12 or 24 Volt LED Strips: The most commonly available and utilized type of LEDs. They are available in numerous configurations, colors, strip substrates, densities, and lengths. Strips are typically 1cm wide and come in lengths up to 5 meters. They come in single colors, RGB, RGBW with different packages of LEDs, but 5050 is the most common size. LED Package: The 5050 is the most common, and will usually contain 3 LED diodes. For an RGB type, there is 1 diode per color. For a white LED in the 5050 package it will typically contain 3 white diodes, and can be considered 3 times as bright as compared to a single color of a RGB version. There are many other packages available, such as RGBW in a 5050, but also smaller ones like the 3528 is common. All the different package sizes can essentially produce the same amount of light per diode. A single red 3528 produces the same amount of light as the red of a 5050 RGB. Changing the density of the LEDs alters the maximum light output. https://www.flexfireleds.com/pages/Comparison-between-3528-LEDs-and-5050-LEDs.html LED Density: Specified in LEDs per meter. 30/Meter, 60/M, 90/M. Increasing the density increases the light output and current consumption. Current Regulation: LED strips always have onboard current regulation in the form of resistors. Each section of LED strip has a set of resistors, one for each color. The resistor values chosen vary between manufacturers, and are chosen to fine tune the output colors, though some may use the same resistor values for every color. Voltage Drop: A significant problem when using LED strip, covered more in the “Power Wiring” section. The strips can only carry so much current before the voltage starts to drop, usually in the areas furthest from the power supply. This causes color inconsistencies between LEDs. It is best to evaluate the project, but expect to inject power every 3-5 meters for best results. Loose & High-Wattage LEDs: Standard LEDs: Covers SMD packages and epoxy cast packages like 3mm, 5mm, 10mm. These types of LEDs come in a variety of light colors, packaging, and lenses. SMD types usually have a clear lens that adjusts the viewing angle of the LED. Epoxy cast packages come in different sizes, in either clear, diffused white, or colored lenses. Colored lenses do not affect the color of the LED, clear lenses change the LEDs viewing angle. These types of LEDs commonly use 20mA to 100mA. High Wattage LEDs: These types of LEDs are large and bright, and normally mounted on heatsinks(commonly called stars), that are then thermally attached to even larger heatsinks. They require high currents and produce a lot of extra heat that must be dissipated through a heatsink to prevent damage and degraded life expectancy. These types of LEDs should only be controlled with a constant current controller or regulators, using resistors produces too much power waste to be effective. Current Regulation: LEDs can not limit the current that flows through them, given the opportunity they will draw so much current they will burn up the diode. No LED should be powered up with out current regulation, LED pixels have internal current regulation and are powered directly from the power supply. Constant Current: The best way to limit current, it is the most power efficient and safest way to power LEDs. Constant-current regulators come in many sizes and capabilities, they come as small as SOT-23 SMD sized for current regulation as low as 10mA, or larger multi-component circuits that can produce high currents. The constant-current regulator must have the same output current(or less) as the LEDs require, some are output a fixed current, some methods have adjustable output currents. Smart/Addressable pixels have internal constant current regulation and do not require any additional current regulation. Resistors: Suitable for low current standard LEDs, quick and cheap, just add a resistor in series with it. See online calculators for help choosing resistor values for various LED forward voltages. Power Supplies: A very important aspect that is often over looked. A proper power supply is usually selected after all the other components. As the required ratings are dependent on the required voltage for the LEDs, and the required current based on how many LEDs need to be powered. This can be fairly complex or simple, not all power supplies will function the same. Power supplies are available in many types and qualities. A poor quality supply can frequently ruin a project or cause numerous headaches. As power supplies can be responsible for inconsistent LED light intensity, data drop outs, flickers/strobes/noise, controller resets, over-voltage spikes, and so much more. Typically the heavier the power supply the higher quality it is, but that is not a rule. Voltage: Check your LED's or pixel's specifications for the required voltage. Typically 5 volts for addressable pixels, some pixels may require 12 volts(WS2811 sometimes). Standard LED strip is usually 12 or 24 volts. Loose LEDs or high power LEDs have various requirements that would be listed on the specification sheet from the manufacturer. Amperage: The more LEDs that need to be powered the higher this requirement is. It is recommended to use a power supply with a rating at least 10% greater than the requirement. The rating of the power supply can be above the amperage requirement, it is fine to use a 3A PSU to power 1A of LEDs, as an example. Calculated Amperage: The calculated amperage rating will be the absolute maximum in theory. In practice, the LEDs or pixels would never draw that much current. It varies significantly and there are other factors that limit current. Calculated Amperage Rating for Pixels: Each pixel is typically 3 LEDs(RGB), a typical single LED draws 20mA maximum, so absolute maximum draw is 60mA per pixel for RGB, 80mA for RGBW. 100 RGB pixels x 60mA = 6000mA = 6 Amps 50 RGBW pixels x 80mA = 4000mA = 4 Amps Calculated Amperage Rating for Standard LED Strip: For 12 volt RGB LED strip there will be 3 RGB LEDs in series per strip section. LEDs in series use the same current at a higher voltage, each color requires 20mA per for a total of 60mA(for RGB) per section. In wattage that is 12 volts x 60mA = 0.72 watts. Actual Real-World LED Amperage Draw: The values calculated above reflect the absolute maximum draw that could occur. In actuality the LEDs will never draw that much current due to a few reasons. In order to reach those values every LED would have to be set to the maximum color values which is usually (255,255,255). Most color sequences will never display those values, but it could easily or mistakenly be done. Additionally, the resistance of the wires, connectors, strips, and interconnects will limit the maximum current that is delivered to the LEDs. If the LEDs did draw their maximum, or close to, current it can cause issues in the entire system. Power supplies could droop and loose their voltage regulation which can cause over-heating in the PSU, controller resets, pixel resets, noise/flickering/strobing, and numerous other issues. That can sometimes require manual reset of the whole system, but disconnecting the pixels and allow a normal startup. Commonly it can be expected to draw 25-50% of the maximum calculated current during normal usage. Power Supply Amperage Draw: Using ohms law a power supply that outputs 12 volts at 10 amps outputs 120 watts, and would draw around 1 amp from a 120VAC outlet. Or 0.5 amp from 240VAC. Power Supply, Batteries: A lot to cover, batteries can make a project more complex. Need more info and references. https://oscarliang.com/lipo-battery-guide/ Voltage: Batteries are never a stable or consistent voltage. A single lithium cell can range from 3v to 4.2v during its runtime. Most LEDs, even 5 volt pixels, can be powered from a single lithium, but below 3.2v battery voltage the blue LEDs will no longer light up. Amperage: Batteries are rated in mAH, a higher value will produce a longer runtime. Batteries have limits on how much current they can provide to the circuit at any given time. If they are over drawn, the voltage can drop significantly and the battery can heat up. Check the batteries specification sheet for discharge curves. Voltage Step-Up: A common solution to achieve a stable 5(or higher) voltage from batteries with a lower working voltage. These can get very complicated, and not all will work as intended or specified. There are many types of step ups, some work better than others for projects. Look online for other tutorials, but in general, many of the common/cheap Chinese step up modules will work, but expect to not be able to utilize their full output current rating. Anyone have links to good step up info? Protection: Applies to all batteries, but lithium based ones especially. Protection can be features like: under voltage, over voltage, over discharge, over heat, short circuit detection. Typically the protection will turn off the current flow from the battery until the fault condition is removed. One of the most important things to watch for with lithiums is under voltage discharge. Summed up, if a lithium battery drops below a certain voltage, it will never be able to be fully charged again and should be replaced. There are some rare circumstances where they can't be used but almost all cases should use what are called 'protected lithium batteries'. Check online elsewhere for more info and details. Wiring and Connectors: An often over looked component for a project, the wires and connectors used to put everything together is equally important as the other project components. Under rated wires or connectors can cause power distribution issues which can result in inconsistent color between LEDs or pixels. Proper power distribution and routing can greatly affect the quality of the project. Power Wiring: As a general rule, use the heaviest gauge wire that is reasonable for the project, especially on the main power runs, such as from the PSU to the LEDs. If there is a long wire run between LEDs or from the power supply, those are the areas that should have the thickest wire. Thicker wire results in a lower resistance for the wire run, voltage levels will drop as it is transmitted through wires, thicker wire has less resistance so therefore less voltage drop. Bad power routing causes LEDs and pixels to be dimmer than expected. It is especially noticeable when a long pixel strand is powered, the end(s) closest to the power supply will be at full intensity, while the pixels further down the strand and further away from the power supply are noticeably dimmer, affecting the color consistency. It is very noticeable on certain projects and must be avoided. The best method is to inject power into the pixel strand as often as possible, these injection points are a direct connection to the power supply or power distribution point with heavy gauge wire. Supplying numerous power 'injections' can be difficult, NLED has a few products to make power injection easier. Products Webpage Data Wiring: For addressable pixels, some require one wire for data(WS2812) and others require two wires for data(WS2801). This wire should not be overly thick, as it can cause data stability issues. Typically 22-28 AWG is suitable. Data Wiring, Long Distance: Note that addressable pixels have a maximum distance between pixels before data stability issues(like noise or cross talk) become a big issue, usually resulting in flickering/strobing of the pixels. Reference the datasheets for specifics for your pixels, commonly 3 to 5 meters is specified. Some solutions for long distance signal stability are to run each data signal wire as a twisted pair, the data wire with a GND/common wire. If the chipset has 2 data wires(clock and data), run a separate twisted pair for each signal. For very long distance communication the signal can be converted to differential signals and transmitted very far distances. www.nledshop.com/miscproducts/ Connectors: A common bottle neck and often not considered. All connectors, whether it is wire-to-board or wire-to-wire have limits on how much current they can pass through before negative effects such as heating and voltage drop become an issue. If an under-rated connector is used, it can cause issues like lower voltage and limited current draw, which can dim LEDs or make them not function at all. Voltage ratings are less important as they are usually a few hundred volts, not an issue with low voltage DC. The actual current ratings of connectors is specified by the manufacturer. Connector Ratings: The common JST(-SM) connectors commonly used for LED pixels are rated for 3 amps, which equates to about 50 RGB pixels. Common tube jacks(2.1x5.5mm or similar) have ratings between 2 amps and 5 amps. For high current applications, like power supply connection and long runs, connectors like XT-30(30 Amps) or XT-60(60 Amps) with heavy wire are recommended. Notes: 1. The barrel jack adapters with screw terminals that are commonly sold with LED strips and pixels are very under-powered, and should not be used for more than 1-2 amps worth of LEDs. 2. Clip on jumpers for LED strips are also under powered and shouldn't be relied upon for much current consumption. |