I would like to ask for your help with a personal project.
First of all, I want to point out that my knowledge of electronics is very limited.
My need
My use case is simple: when I open a door of my cabinet, I want to turn on two LED strips.
I am planning to use an Arduino board to connect the door status (detected via a reed switch) to the activation of the LED strips.
The LED strips have the following specifications: COB LED strip – 24V – 15W per meter.
Eventually, my cabinet will include:
4 reed switches
8 LED strips, each 3 meters long, which may be lit simultaneously.
For power supply, I only have a single 230V outlet nearby.
My questions
Powering the system
How can I continuously power the Arduino board and, when needed, the LEDs?
I was thinking of using a 230V → 24V adapter for the LEDs and a 24V → 5V converter for the Arduino board.
Wiring
Some LED strips will be located more than 3 meters away from the Arduino board.
What type of wire/cable should I use? (Until now, I have only worked with cables for BreadBoards).
Power management
I am not very familiar with power and amperage concepts...
Are there any precautions I should take (for example, the use of resistors, etc.)?
I would like to thank in advance everyone who is willing to share their expertise with me.
If I understand correctly, when you open the cabinet door, you want the LED strips to light up and when you close them, they turn off, right? Because if that's what you want, why the hell do you need a microcontroller!?
Maybe the reed switches if they can handle the current. Or maybe a microswitch or some other kind of spring operated switch, like the switch that turns-on your refrigerator light or the switch that turns-on the interior lights when you open your car door, etc.
...The switches on my car doors do actually have some kind of electronics attached because they stay-on for a moment after I close the door and then fade-out, etc. But my older vehicle just goes on/off like regular switch.
I understand now that using an Arduino board might be a bit overengineered and that simple microswitches would do the job.
I’m still wondering about the question of powering the LEDs.
I believe I understood that to power my 8 LED strips in series I would need 8x24V = 192V, whereas wiring them in parallel would only require 24V.
Preferring the latter option, I was thinking of using a 230V —> 24V adapter like this one:
RSP-75-24
AC-DC Single Output Enclosed power supply; Output 24VDC Single Output at 3.2A; PFC
Does this seem like a suitable choice?
Also, are there any precautions I should take if I decide to wire 30V / 5A microswitches in this way?
Total power of your strips will be 8x3x15W = 360W, so you need more than 15A power supply.
To my honest opinion, that quantity of light is not necessary for any normal cabinet. Maybe for a warehouse...
If you didn't purchase your strips yet, look for something that has 10% of that power.
No. Because of the way the strips are wired internally, if you connect them in series they will still require 24V. Inside the strip, the + and - power conductors run, unbroken, the entire length of the strip. Groups of 6 adjacent LEDs are connected in series between the power conductors. When you connect two strips in series, in reality you are connecting the power strips, making one longer strip.
However, with so many LEDs, the current will be quite high, and the power conductors on the strip can only carry so much current before the voltage begins to drop, causing the LEDs along the strip to have different brightness. So connecting the strips in parallel, with heavy-gauge external wires, limits the current any individual strip has to carry and keeps the brightness more consistent.
