Hi guys,
I don't know if this is the right section (or forum), but I have a question about RGB LEDs matrix
There are some that are very cheap, some that are way more expensive.
Can I control the color per-LED on the cheap matrix? Or I just select a color and lights up every LED? Is programming the 2 the same?
Thanks
The expensive one is far easier to drive and use. It uses only one data line and does not use any CPU power to keep it shining.
The cheap one needs extra multiplexing components and a lot of wiring up and requires constant refreshing to keep it lit. It will also be not as bright as the expensive one.
The cheap matrix does not require multiplexing by the Arduino, it has an ht1632c which performs the multiplexing (probably two, actually).
The main disadvantage of the cheap matrix is that each led can only display one of 7 colours (red, green, blue, yellow, cyan, magenta, white). The matrix can be dimmed overall, but there is no dimming of individual leds and no colour mixing to create more colours.
The expensive matrix allows individual dimming of each led and colour mixing to create a large range of colours.
Thanks!
So, I'm definitely gonna buy the expensive one.
Can you guys help me on how to control it? I never did something like that before
If we can help, we will. The seller will probably be able to give you some example sketches to begin with.
Shop around, maybe you can find that matrix cheaper.
Also, you will need a separate power supply for the expensive matrix. At least 15A, 5V. The reason is that, as Mike said, the expensive matrix is far brighter than the cheap one (too bright to look at when up close). More brightness requires more current.
What project do you need the matrix for? Maybe the expensive matrix is not really suitable.
I'd like to use it for displaying images (I followed this guide: Netopya Planet - Show images with an Arduino on a RGB LED Matrix), displaying animations, the clock and other things that I'll add in the future. The "windows" can be switched by a button.
I can't find that matrix cheaper, the price is always around 40€
Is there any other good 16*16 RGB matrix a little bit cheaper?
There is another type which is cheaper. They come in 16x32, 32x32 and 32x64. These are the type Mike was describing, where the Arduino must perform the multiplexing, dimming and colour mixing. An ordinary Arduino such as Uno is only just powerful enough to run these displays, in a limited way. There may be not much program space and speed left for your application. These displays are not really suitable for beginners. Unfortunately, this is the type used in the guide you gave the link to.
So, should I go for an Arduino mega?
Found this!
Perhaps Mega. It has more ram and flash memory than Uno/Nano/Micro. But it is the same speed, so you may still be limited in the number of colours available, if you follow that guide.
The ws2812b matrix does not need so much speed. But again, if using an Uno/Nano, most of the ram memory will be used, leaving very little for your programs. And the guide you linked to may not help you very much because it does not use that type of matrix.
If you want more speed and more memory, you will need to look at something more exotic, such as a Teensy 3.x or an esp8266. But again, this may not be simple enough for a beginner.
lorenzoalinari:
Found this!
You seem to have forgotten how to post links. You did it correctly in your first post.
Can you figure out the price for the 16x16 on that page? I cannot find out how to select which model to find out the prices for each type. One of the choices is 8x8 which will be much cheaper than the 16x16.
PaulRB:
Perhaps Mega. It has more ram and flash memory than Uno/Nano/Micro. But it is the same speed, so you may still be limited in the number of colours available, if you follow that guide.The ws2812b matrix does not need so much speed. But again, if using an Uno/Nano, most of the ram memory will be used, leaving very little for your programs. And the guide you linked to may not help you very much because it does not use that type of matrix.
If you want more speed and more memory, you will need to look at something more exotic, such as a Teensy 3.x or an esp8266. But again, this may not be simple enough for a beginner.
How much are colors limited?
Btw, once got the picture in text format, isn't quite the same for every matrix?
PaulRB:
You seem to have forgotten how to post links. You did it correctly in your first post.Can you figure out the price for the 16x16 on that page? I cannot find out how to select which model to find out the prices for each type. One of the choices is 8x8 which will be much cheaper than the 16x16.
I used the site from desktop the first time, now I'm on the mobile. The matrix there costs about 30€
There exists a shield + library for the Teensy 3.1 to drive the 32x32 matrix with 24-bit color. It can be programmed with the Arduino IDE + Teensyduino.
If you want to stick with the Arduino Uno / Mega, I´d recommend to go for a 16x16 WS2812 matrix if you need 24-bit color.
edit: For the beginning you can use the Neopixel lib. For advanced projects and animations there is the FastLED lib.
You can drive the 32x32 multiplex matrix with an Uno, but just at low speeds and with reduced color resolution (4096 colors). There is a library as well.
Helmuth:
There exists a shield + library for the Teensy 3.1 to drive the 32x32 matrix with 24-bit color. It can be programmed with the Arduino IDE + Teensyduino.If you want to stick with the Arduino Uno / Mega, I´d recommend to go for a 16x16 WS2812 matrix if you need 24-bit color.
You can drive the 32x32 multiplex matrix with an Uno, but just at low speeds and with reduced color resolution (4096 colors). There is a library as well.
In fact the matrix I wanna run is 16*16..
As Mike said:
The expensive one is far easier to drive and use. It uses only one data line and does not use any CPU power to keep it shining.
Driving the WS2812:
For the beginning you can use the Neopixel lib. There are many good tutorials arround.
For advanced projects and animations there is the FastLED lib available.
Keep in mind that you need a good power supply for the 16x16 WS2812. The leds need at full white up to 15A.
Helmuth:
As Mike said:Driving the WS2812:
For the beginning you can use the Neopixel lib. There are many good tutorials arround.
For advanced projects and animations there is the FastLED lib available.
Ok thanks!
So, with the 16x16 I will be able to run all the colors?
So, with the 16x16 I will be able to run all the colors?
Well, what means "all"?
It has 38 bits for R, G & B - so you can display 256256*256 = 16777216 different colors.
You said that with the 32x32 one I couldn't display only some colors. Btw, I think that 16777216 colors is ok
I also found this
Anything based on WS2812B leds will be fine for you.
You said that with the 32x32 one I couldn't display only some colors.
Yes, with an Uno / Mega you can´t.