LED matrix projects are all over the place, but this one is interesting for its simplicity: it’s an LED matrix that is driven straight from an ESP8266 board. [Ray] put it together as a quick project for his students to teach the basics of LED programming.
It’s built using a WS2812 LED matrix board he designed himself and his own ESPToy ESP8266 dev board. But the gist of the hardware is simply an ESP8266 and some WS2812’s. Where this gets interesting is with the user interaction side of things. The ESP makes WiFi and web serving easy, and [Ray] has build a simple HTTP GET API into the firmware. This is a great combination for the web dashboard and JavaScript-based animation programs [Ray] is demonstrating in the video below.
Just get on the same network and load up the module’s WiFi address for a graphical representation of the 5×7 LED matrix. Pick a color, turn pixels on or off, or choose a predefined pattern and send it to the hardware. This is a powerful way to get use input and with this as a guide it’s fast to set up for pretty much an application you can think of. Just work your way through the documents he put together for the workshop (Zip file link), including all of the code and the slides he used to run the workshop.
Very good stuff, this one. Well presented too. I think I’ll have a play with it.
I have turned an ESP8266 into an ArtNet node. This allows me to control my ceiling LEDs with lots of dedicated programs, including professional ones, if I were so inclined.
Lowest I could do with WS2812 is 20MHz PIC16F overclocked at 24MHz with critical routines programmed in asm. That would be 6MHz in ATMega (Arduino) terms because PIC uses 4 clock cycles for single instruction. That LED chip is much more forgiving than datasheet says, the biggest challenge is not to exceed period which chip considers end of command. ESP8266 runs at 80 or 160 MHz and has plenty of power to run those LED chips.
I really love the scalability of featured board, and 5×7 design is much more practical for big text displays than 8×8 or 4×4 available on eBay.
Yea I get that WS2812s are cheap, but I wish that the chinese board manufacturers would move on to APA102 and the like for large arrays because you can drive them with SPI. Even the crappiest little micros have hardware SPI support, or you can control a handful with bitbanging and NO timing requirements. With the ability to use DMA+SPI in ARMs, it means you can trivially drive massive arrays with tiny quantities of code without doing nasty hacks like we’ve seen linked here a few times recently (OctoWS, DMA-to-PWM and the like).