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English (United Kingdom) How to make your own automatic staircase lighting using LED strip or spotlights. Detailed instructions.
Background.
Creating automatic staircase lighting has long been an interesting task for many designers and electricians. Just a couple of decades ago, staircases with steps that turn on sequentially when you enter them were possible only in fantastic feature films. With the advent of LED strips, this task no longer seemed fantastic, but it was about organizing the smooth sequential switching on of each step one after another when entering the staircase, while taking into account the direction of movement. It is to this task that we have devoted the last 15 years. Our company, as one of the pioneers on the market, was the first to develop and introduce into mass production simple and affordable controllers to solve this problem. And despite the availability of microprocessors, for most of the controllers on the market, even now it remains unattainable to smoothly turn on each next step. Most controllers on the market, as before, simply turn on or off the desired channel. Why? It's simple: most microcontrollers do not have the required number of outputs using PWM and dimming individual channels is simply not possible. Our company developed and implemented a dimming method using binary modulation, allowing you to planically turn on and off the LEDs of each step. At the beginning of 2017, a company from China purchased several controllers from us, after which Chinese controllers for staircase lighting appeared on the market, but since the chip of our microprocessor has read protection, they could not decode our code and copied it as is. Including several errors that were present at that time. Without the source code, they cannot eliminate errors and bring the controller to the perfect state as we have, so they simply sell an old copy of our first controller, which has long been discontinued.
How to make your stairs fantastic.
Today we will tell you what options for lighting stairs can be created, how to calculate and implement it, what materials and equipment you will need.
Staircase lighting options:
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Illumination of each step with a monochrome (single-color) LED strip. Part 1 of this material.
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Lighting each step with an analog multi-color RGB strip. Part 2 of the material.
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Lighting each step with an addressable color ARGB LED strip. Part 3 of the material.
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Staircase lighting using LED fixtures mounted in the wall. Part 1 of the material.
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Staircase illumination using addressable LED strip laid parallel to the stairs in the wall, in the railing, etc. Part 4 of the material.
Which option is right for you is up to you.
Illumination of each step with a monochrome (single-color) LED strip
Illumination of each step with a monochrome (single-color) LED strip
The first and most common option is to install a monochrome LED strip in the groove under each step along its entire length. To implement this lighting option, a monochrome (single-color) LED strip is usually used. A strip segment for each step is connected to the corresponding controller channel. A sensor is installed at the entrance and exit to the staircase, which initiates the inclusion of these segments in a given direction.
At this stage, you will have to decide on the choice LED strip, type and location of sensor installation, calculation of required power supply, selection of controller for LED staircase lighting control. Let's take a look at everything in order.
1. Choosing an LED strip.
The first criterion for choosing LEDs is dimming support.
As is known, monochrome LED strips, as a rule, do not all support dimming using PWM (pulse width modulation) well, as is usually indicated by the inscription on them. But recently, there has been a huge number of cheap (sometimes cheap ones are sold at a high price, pretending to be high-quality) Chinese-made LED strips on the market, assembled from low-quality LEDs, which may not support PWM dimming and at the same time flicker noticeably. This is due to the fact that PWM dimming is implemented by changing the frequency of turning on / off the LEDs with a certain frequency (usually not below 50Hz) while the lower the frequency, the weaker the LED glows, visually the human eye perceives this as a decrease in brightness, although in fact the brightness is not variable, it changes. This is necessary because the LED cannot change the "spiral voltage" like in old incandescent lamps, when the required voltage and current are applied to them, the LED simply turns on. The option of changing the brightness by changing the current for the LED is not desirable, because this can affect its service life. Therefore, PWM is used for LEDs. Cheap LEDs are not able to provide the required frequency, so flickering noticeable to the eye occurs due to the LED skipping the PWM duty cycle.
The second is no less important - the required brightness.
When choosing an LED strip, you should consider that the backlight will turn on for you in a dark room. At the same time, the human eye in the dark adapts to a low level of lighting, turning on too bright steps can cause glare or discomfort and cause injury if glare occurs on the stairs. The overall brightness level of the stairs should not cause glare. All these parameters are regulated by GOSTs and international standards. For diffused, indirect lighting, the brightness should exceed 550Lm per linear meter. These parameters are met by an LED strip based on SMD3528 LEDs with a density of 60 LEDs per meter. Typically, such strips have a brightness of 470-510Lm per meter, depending on the color temperature and manufacturer. Warm shades have a lower luminous flux, colder ones are more intense and may not be comfortable in the dark. It is optimal to use warm or neutral tones. But here you should take into account the color of your stairs, because as a result of mixing colors, the shades may change and it is better to illuminate black stairs with neutral or cold light.
The third parameter is the choice of LED strip by supply voltage
As is known according to Ohm's law, the higher the voltage, the lower the current. And what does this mean when designing staircase lighting? Savings and risks. For example, Above, an LED strip based on SMD3528 LEDs requires 3.2V power for each LED and 20 mA of current for each LED. Then 60 LEDs require 1.2A of current. If the LEDs are assembled in series from 3 LEDs connected in series, then 9.6V will be required for their power and the current per segment of 3 diodes will be 20mA and then 60 LEDs will consume 400mA (0.4A). Since 12V is usually used for such strips, a current-limiting resistor is included in the circuit. If 6 LEDs are connected in series, then the supply voltage will be 19.2V, and the current for a group of 6 LEDs will be the same 20mA, and 60 LEDs will require a current of 0.2A (200mA). In fact, reducing the current allows you to save on the cross-sectional area of the wires connecting the LED strips. For example, if your copper wire is 10 m long, then using the formula
To calculate the cross-sectional area of a wire with a voltage drop of no more than 5%, we use the formula:
S = (2 * I * L * ρ) / ΔU
Where:
- S - cross-sectional area (mm²),
- I - current (A),
- L - wire length (20 m),
- ρ - copper resistivity (0.0175 Ohm·mm²/m),
- ΔU - permissible voltage loss (5%).
Substituting the values into the formula, we get the following results:
- For 5 V and 1.2 A: 4 mm².
- For 12 V and 0.4 A: 0.5 mm² (0.75 mm² recommended).
- For 24 V and 0.2 A: 0.25 mm² (0.5 mm² recommended).
If take into account that you will need a lot of wires for all the steps, then you will get a very significant saving not only of money, but also of the space where you will have to lay all these wires.
As for the risks, they are associated with errors during connection and the occurrence of induction currents in the wires. For example, the controller for lighting the stairs SmartStairway SS-26 LCD Pro starting from incorrect connection or the occurrence of induction currents in the sensor wires, since in addition to protection against electrostatic discharge, it also has protection against overvoltage on digital inputs. But other controllers do not have protection to this extent. Therefore, if you accidentally mix up the wires and apply high voltage to the digital input of the controller for a long time, the controller will burn out. If, as a result of incorrect laying of the power wires of the LED strips and sensor wires, you will have an induction current in the data wires (and with a supply voltage of 24V and excess power wires and sensor wires wound into a coil, you can create a "step-up transformer" with a primary and secondary winding of 1000 volts). Therefore, a lower voltage reduces the risk of damage to the controllers due to inept connection and laying of cables.
Therefore, it is better to choose a middle ground and use 12-volt strips with minimal power. Please note that the controllers SmartStairway SS-26 and the power amplifier SmartStairway APS-21, or even better, choose the controller SmartStairway SS-26 LCD Pro which allows you to connect loads up to 4A per step.
2. Calculation and selection of a power source.
Quality of the power source. The power supply is no less important component of your staircase lighting. Low-quality switching power supplies usually do not have protection against short circuits and overloads, especially since they do not have power filters and produce questionable pulses at the output (high level of ripple) and have a large number of interferences. Interferences are not particularly critical for monochrome analog LED strips, but can become fatal for addressable ARGB LED strips and make the entire project inoperable, causing flashes, artifacts and complete inoperability of such strips. In our case, the analyzed version of the staircase lighting, this can manifest itself in the flickering of LEDs when using dimming at low brightness, up to complete unusability. Among the inexpensive Chinese-made power supplies, MeanWell power supplies have proven themselves quite well, but here too you need to be careful and not buy a fake, because any popular product is always at risk of counterfeiting.
Power calculation. When calculating the power, you need to add up the total power of your entire LED strip and add a power reserve of at least 20% to the resulting value. After that, choose the closest power supply from the available range. Let's consider the example of a staircase with 21 steps 1 m wide, on which we will install an SMD3528 DC12V 60LED/m LED strip (300 LEDs in a 5 m roll). In total, we use 21 meters of LED strip, according to the specification of this LED strip (usually indicated on the packaging), the power consumption of this strip is 4.8 W/m. It is not difficult to calculate the current strength, if it is not indicated, you need to divide the power by the supply voltage 4.8W/12V=0.4A per 1 meter. Then for 21 meters of tape we will need a power of 21 m*4.8 W = 100.8W or 8.4A. Add 20% (not less than 15% for high-quality power supplies) of the reserve and get 120.96W. In this case, we have practically reached the existing nominal value of the available assortment and can use a 120W (10A) power supply or choose a larger one, for example 150W.
Probably one of the most difficult tasks is the selection of sensors. When choosing sensors, you should take into account the place of their installation, the presence of railings and the material from which they are made, the passage zones in the field of view of the sensors, etc.type of sensor itself and properties characteristic of this type of sensor. There are several types of sensors:
- Pyroelectric sensors
- Infrared sensors
- Ultrasonic sensors
- Laser sensors.
Pyroelectric sensors of our production have a limited field of view angle of 45 degrees (usually these sensors have a viewing angle of about 180 degrees) and are able to detect the movement of objects that are 10-15 degrees Celsius warmer than the surrounding space at a distance of 5-7 meters. For sensors of this type, silicate glass is not transparent. What does this mean? This means that if you install this sensor on the wall, so that it looks towards the stairs, and behind the stairs there are passage areas where there is movement of people, then the sensor will turn on the light on the stairs every time it sees movement. But if the stairs are limited by railings made of silicate glass or other material that is not transparent to IR rays, then everything will work correctly. The best option for sensors of this type is when the sensor is installed so that it can see the opposite wall or the stairs are limited on the other side by a material that is not transparent to IR rays. If the stairs do not have railings and the sensor looks into the passage area, then it is better to choose a different type of sensor. In this figure, you can see that the sensor installed in the specified place will trigger switching on every time it sees the movement of a warm object in the marked yellow zone. Please note that the sensor does not care whether it is a living object or just warm air masses moving from a heated floor or a heating device. The sensor does not have the ability to determine what exactly is moving in the specified zone. Therefore, in this example, a pyroelectric sensor is clearly not suitable.
Where is a pyroelectric sensor ideal? Below you can see examples of suitable installation options for this sensor. These are places where the sensor's range is limited by a wall, railings or other surface that is not transparent to IR rays. Please do not forget that in the idle state the sensor on the signal wire has a low signal or logical zero. With a sufficiently long wire, especially if it is laid next to the power wires of the LED strips, the wire acts as an antenna in which induced currents can occur, which can cause false switching on of the staircase lighting when the voltage reaches above 1V, i.e. the occurrence of a logical one. Despite the fact that the controller inputs are connected to ground through a 22kΩ resistor, the induced currents can be strong enough for the controller to perceive them as a logical one. Therefore, use shielded signal wires. Or UTP wire. Be sure to ground the wire screen or ground the power source.
This type of sensor has an infrared emitter and an infrared receiver. Unlike a pyroelectric sensor, as long as there is no obstacle in the sensor's field of view, it sends a high signal (logical one) to the digital input of the controller. When an obstacle appears in the sensor's field of view, the sensor is pulled up to zero and a low signal (logical zero) is sent to the controller's input. Thus, the presence of inductive induction in the sensor wires and other interferences do not matter, since in the absence of an obstacle, a high signal is sent to the input and the interferences are not important. When pulled to zero in the event of a sensor tripping, all obstacles will also be pulled to zero and the controller will correctly process the tripping. Infrared receptors have a multi-turn trimmer resistor on the back of the case and an indicator LED, which allows you to adjust the tripping distance from 3 to 80 cm. Like all other sensors, they have certain disadvantages, for example, they may not work correctly with surfaces that absorb infrared radiation and are sensitive to the level of illumination, in bright light they may not work at large distances of 30 cm and further. This must be taken into account when choosing this type of sensor. Also, if your stairs have several spans and you plan to place the sensors oneIf the sensor is opposite to the other, then this is not desirable and can cause erroneous operation of the sensors. Where can you use detectors? In any place where there is no bright light and you need the sensor to turn on the light if a reflective obstacle appears in its visibility zone at a distance of 75 centimeters or less. Keep in mind that the sensor's detection angle is about 15-20 degrees, so it should not be installed too close to the surface in the side planes. that is, above the floor or from the step no closer than 20 cm. Since the infrared sensor is not critical to induction interference, it is not demanding on shielded wires, which is an absolute plus if you already have a regular wire.
Ultrasonic sensor.
The ultrasonic sensor, like the infrared one, is designed to measure the distance to an obstacle and compare it with the value you set. If the distance becomes less than the specified value, the controller will turn on the light. The principle of operation of ultrasonic rangefinders is based on the reflection of a sound wave. The sensor has an ultrasound emitter and a receiver. When meeting a surface, the sound is reflected and returns. Since the speed of sound is known at a given atmospheric pressure and temperature, it is easy to calculate the distance to the object. At the same time, technologically, this type of sensor cannot determine the calculations for surfaces made of sound-absorbing materials, if the surfaces have a complex shape, reflecting sound at different angles, creating reflection distortion. Therefore, when choosing a location, the distance to the side surfaces, stairs and floor should be taken into account. It is recommended to install the sensor no closer than 50 cm. Since sound reflected from the floor or from the end of the step can distort the data and cause false alarms.
The video below shows an example of the operation of an ultrasonic sensor.
Take this into account when choosing a location for the sensor. It should also be noted that a 4-wire shielded wire no longer than 8 meters long should be used to connect ultrasonic sensors, since these sensors are high-frequency devices that are demanding on the quality and length of the wiring. The operating distance is set on the controller display. You simply specify the distance in centimeters for the upper and lower sensors, respectively. The younger version of the SmartStairway SS-26 controller also supports ultrasonic sensors, but the operating distance is set by placing an obstacle at the desired distance opposite the upper and lower sensors at the same time and pressing the corresponding button in one of the settings menu items. In this case, the controller measures the distance to the obstacle and writes it to memory. This is not very intuitive and is somewhat difficult for some buyers. Therefore, to use these sensors, we recommend choosing older models with a display.
We also offer a precision ultrasonic sensor in a miniature moisture-proof housing SmartStairway US-SR042 Mini. This sensor allows you to measure distances from 25 to 150 cm, which is very convenient when installing at the end of a step or in difficult places where other surfaces or steps are located nearby. It has miniature dimensions and can be installed in a hole with a diameter of 20 mm. The sensor consists of an ultrasonic module in a sealed housing that matches the RX/TX module. The sound-emitting module already has a 2.5 meter long wire and thus allows you to increase the installation distance to more than 10 meters from the controller.
This sensor can also be used to illuminate external stairs, as it has an IP67 protection class.
A laser rangefinder is a sensor that measures distance using a laser beam, like an infrared or ultrasonic sensor, it has a built-in laser emitter and a receiver of the reflected signal. Its main advantage is its miniature size. It has a size of 1.2x3.5 mm. You are probably familiar with these sensors, they are widely used in proximity sensors in modern smartphones. This sensor is used only in the controller model for illuminating stairs and corridors with a built-in ARGB LED strip, SmartS.tairway SL-28. This sensor is already built into the controller housing. The controller itself is also miniature and is made in a housing made of a profile for LED strips. Now we will not consider this sensor and controller, since you will find an overview of it in part 4.
LED staircase lighting using lights built into the wall that are sequentially turned on.
Here everything is the same as with the lighting of the steps, but with the cancellation of the choice of LED lights instead of strips. This is a very simple task, which for some reason causes a lot of difficulties for our customers. Let's try to figure it out.
What types of lamps are on the market and how do they differ?
- LED lamps are designed to operate on 110/240V AC power
- LED lamps are designed to operate on 12/24V DC power
- A typical lamp fixture for incandescent, halogen, or LED lamps.
The most troublesome are high-power LED lights with a 110/240V AC power driver. As can be seen from the design of the light in the photo, it has several high-power LEDs, usually 1W or 3W each, a housing and a power driver. That's right, the driver, because LEDs require a power source stabilized in terms of current, not voltage, so if you use 1W LEDs, the driver provides a stable current of 300-320mA, and if 3W LEDs, the current will be 700mA, and the voltage will depend on how many LEDs are connected in series. Therefore, if you thought that you could simply discard the driver and connect this lantern to a controller with a 12 or 24 volt power supply, you are mistaken. The lanterns and the controller can burn out and the only question is which one of them will burn out first. Therefore, if you are going to use such lanterns, the power driver cannot be simply discarded, it must be replaced with a suitable driver for DC12 or DC 24V power supply with the appropriate current for these LEDs. You will also most likely have a problem with smog, because most of these drivers do not support smog, and therefore at low brightness the lights may not work at all, and switching on will be done in jumps. Therefore, it is not a very good idea to use such lights. But if you still really need it and you already have such lights, then you can still use them by installing high-power current-limiting resistors, or drivers of the appropriate current that support smog. If you need it, you can write to us, indicating the detailed characteristics and photos of your lights, it is advisable to disassemble 1 light and provide a photo of its contents. The more information, the more detailed and high-quality help.
The second type are lights designed for DC 12/24V power supply. As a rule, they are used in cars, motorcycles and boats. This is a much better option, which will most likely suit you without any modification, the only thing you need to pay attention to is whether it supports dimming, if so, then make sure that the power does not exceed the capabilities of the controller and you can use them. These lights usually already have a built-in driver, if it is a branded light, or a regular current-limiting resistor, if it is a cheaper option. But both will work. The main thing is that they do not exceed the permissible current per 1 channel of the controller for staircase lighting.
The third type is probably the cheapest and best. You choose a lamp fixture that suits you and satisfies you in shape and design, it doesn't matter whether there are lamps or not at all, the main thing is that they have a pleasant appearance, price and quality that will satisfy you. You should also choose LED lamps with the appropriate socket, voltage and power for them. At the same time, pay attention to the amperage of each lamp so as not to exceed the permissible amperage for the controller you have chosen and whether it supports smoking. Lamps,that do not dim (cannot be dimmed) will not work correctly and may turn on and off intermittently and flicker.
After you have chosen your lights and lamps, calculate their total power and proceed to selecting a power source and controller for the stairs, as described above.
