Hello everyone, I need some advice on how to continue with this project.
I want to make a sort of clock, but instead of using servo-motors to swing the clock pointers around, I wanted to make it with LEDs, something like a ring with 12 spaces, each space divided into 2 so the top sections would be for hours, the bottom ones for the minutes, that would give me 24 leds and that is quite a bit of pins to plug into a microcontroller.
I thought in using the ‘NeoPixel Ring’’ or even the Circular LED Bargraphs, but none of them come in a ‘12 led package’ as I’d need to the clock. The caseing for the leds is not a problem as I have a few friends with 3D printers that I could borrow to build a custom and fit case, my problem relies on how to use as few pins as possible.
Anyone here got an idea on how I can build an addressable LED ring so I don’t have to wire 48 pins to a microcontroller? I thought in buying a ‘NeoPixel Stick - 8 x WS2812 5050 RGB LED’ and breaking it apart, place them in a ring and just wire them back as they were before but I’m not sure if I could go and stick 4 extra leds to the same line of LEDs as it was only built to operate with 8.
Also, a separate question, would I be able to give a common anode pin to a lot of LEDs? Like, having the LEDs receive power from different output pins of an microcontroller but then all connect to the same pin and connect it to the ‘ground’ of the microcontroller?
stillnex:
Anyone here got an idea on how I can build an addressable LED ring so I don’t have to wire 48 pins to a microcontroller? I thought in buying a ‘NeoPixel Stick - 8 x WS2812 5050 RGB LED’ and breaking it apart, place them in a ring and just wire them back as they were before but I’m not sure if I could go and stick 4 extra leds to the same line of LEDs as it was only built to operate with 8.
You certainly could do the above or buy the pixels individually and wire up your own 24 pixel string (or two 12 pixel strings). Both SFE and Adafruit sell them.
https://www.sparkfun.com/products/11821
http://www.adafruit.com/products/1655
Or you might use something like 2 of these. (note it’s WS2801 not WS2811, WS2812a/b)
https://www.sparkfun.com/products/11020
Or get one and add …
https://www.sparkfun.com/products/10866
Or even better (25 LEDs) …
http://www.adafruit.com/products/738
http://www.adafruit.com/products/322
Lastly you could use shift registers to expand the output of 2-3 pins into 48.
https://www.sparkfun.com/products/734
https://learn.sparkfun.com/tutorials/shift-registers
Thanks for the help, I think I will just buy a couple of pixels and wire them myself, looks like it will be much cheaper and will allow me to work it just the way I need.
On the Shift register: Never heard of them before, I bet would be a cool thing to learn but right now, on this project, I’m trying to be really minimalistic and I think that using the pixels would be better than sticking another chip to it. But I’m definetely taking a look at it, should fit perfectly in another project I have in mind.