This is my first post here, I hope to find a great community as in other places.
I'm rather new to electronics and I have been studing Arduino since a year ago on and off.
I'm not a pro but I'm willing to learn and study further. I got this as a new hobby.
I want to do an RGB led strip arduino VU Meter
I got some general knowledge but not the specifics to make it. I have tryed to look into many places for information but somehow I can not find a whole tutorial on how to do it.
I rather do it with a regular rgb 5050 led strip rather than a WS2812B led strip
I own both and I'm open to suggestions on what wiuld it be the best way to do it.
I do not know if it's possible to do both functions the VU meter plus the control of the color of the led strip section. Or is better to let arduino do the VU meter part and use a separate rgb led controller to controll the colors of the leds.
I want to do it in like 3 levels
One level is 3 sections of 6 leds each
One level is 3 sections of 6 leds each
One level is 4 sections of 6 leds each
I know I must use transistors but I would like to know wich ones to use. and how to make the formulas or calculations for it. Also for the resistors for each pin.
Can you explain your design further please. Why are you using rgb strips instead of single colour strips? Could you make each level from different colours of single colour strip? Single colour strips are available in red, green, yellow, white and perhaps other colours. It would be much simpler if you can use those.
If you use ws2812b strips, you will not need transistors. But it would be a waste to use those if the colours in each level never change.
I ask because I already have an RGB 5050 Led Strip and also I got a WS2812 Led strip
I do not own individual color rgb strip. And it take a long time to arrive to my country (Venezuela)
1-) LM3915 as VU Meter but I do not know how to calculate the transistors not to burn the IC, Also I need help on how to connect a separate rgb led controller (Wich I also got)
2-) RGB Led Strips with Arduino (Each step of the Acrilic Vu Meter will be of 6 RGB Leds for a total of 10 steps)
I guess I need to use also a PWM led driver to be able to control each step individually (on each step al the leds will have the same colors)
3-) Use a WS2812 led strip. As I'm writing this now I'm also reading as much as I can about that kind of leds and arrays.
This is a liner output device, to make a VU display you need a LM3916.
The output of this chip is a constant current pull down. So you can replace the LEDs with resistors (2K sould do but it is not critical ) and take the output pin to the base of a transistor. The transistor does have to be able to handle the current of the strip.
I hope it's more clear now
Sorry not much.
, Also I need help on how to connect a separate rgb led controller (Wich I also got)
Can't answer that without knowing what sort of controller you have.
Somehow this guy manage to do what I wanted to do but right now I'm kind of lost n the connection adn type of transistors to use.
BJT? Mosfet? N or P channel? Resistors at the base of each output of the IC pins where the led strip is going to be?
The post is in german and although I translated it with google translation, my knowledge of electronics is basic I'm learning so I do not understand fully what is says there.
It is possible to do it with the LM3915. Matter of fact yesterday I finished my fisrt circuit basd on that IC
I think you are misunderstanding.
The LM3915 will generate a bar display but it is not a VU display the relationship between the input volume and the display strip will be logarithmic not in Volume Units. Yes it will bounce up and down with the volume of the signal but they will not be in Volume Units without using the LM3916 chip.
Look at the circuit on page 5 of the LM3916 and compare it with the circuit on page 7 of the LM3915 data sheet. You will see that the resistor chain has different values so giving you a different relationship between the input voltage and the LED lit.
but right now I'm kind of lost n the connection adn type of transistors to use.
The German web site is telling you what I said in reply #2. Replace the LED with a pull up resistor. Then the output is a signal that will be 0V or 5V. With this you can use a transistor to switch a much heaver load than a single LED.
BJT? Mosfet? N or P channel?
You can use any of these.
Basically use a P channel FET or a PNP transistor for driving a 5V load, or an N channel FET or NPN transistor for driving a higher voltage load. It all depends on what sort of strip you have. They are normally either 5V or 12V working with built in current limiting circuits. This shows you how to use a 12V strip using NPN transistors or N channel FETs. Usage | RGB LED Strips | Adafruit Learning System
In place of the Arduino, just connect it to the output of the LM3915 chip with the pull up resistors fitted as mentioned above.
so I do not understand fully what is says there.
