In recent posts I’ve covered how to use LEDs and how to use shift registers and even how to combine shift registers and LEDs to control numeric displays. In this post we’re going to use 64 LEDs in an 8×8 LED grid.
In previous tutorials I showed how to use seven segment displays, how to use shift registers and how to daisy chain shift registers, and talked a bit about persistence of vision. In this tutorial we’re going to combine shift registers and seven segment displays to make an Arduino control two four-character seven-segment displays, a task that (at first glance) might not seem possible.
The first time using a new microcontroller is what I call funstrating, especially if you don’t have clear instructions. We’ve done the hard work of figuring out the NodeMCU drivers and NodeMCU Arduino IDE setup for you. Read on for the two steps that have to be done only once. More helpful info at the end, too.
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Shared anodes and cathodes are a common technique used to control lots of LEDs with a small number of microcontroller pins. I’m going to talk about why share anodes and/or cathodes. Then I’ll show an example of shared anodes, an example of shared cathodes, and finally combine the two for some more impressive results.
In the previous post we learned how to use a 74hc595n shift register. I mentioned briefly that shift registers could be daisy chained – connected end to end – to increase the number of available connections without using extra resources on the Arduino. In this post we’ll cover why daisy chain shift registers, how to plug them together, what changes in the code, and show some examples in a video at the end. (more…)
