Geeks With Blogs
Joaquin Jares Just another geek's blog November 2010 Entries
DEMUX Chaining
There are several ways to chain demux IC’s to get more outputs than the ones that a single IC can get you. In these posts I’ll explore the ones I could find and use successfully. The first one has to do with the differences of inverting and non-inverting IC’s. In this video, I have 2 iC’s driving 16 LEDs. With this configuration I could drive as much as 64 LEDs with these 2 IC’s. I simply didn’t have the patience to connect them all: 16 LEDs with 2 IC’s In my previous post I mentioned that the 74HC138 ......

Posted On Sunday, November 14, 2010 9:23 AM

DEMUX with Netduino
In my previous post I used a lot of transistors (not very successfully, I might add) to drive 4 LEDs with 2 digital GPIO pins from a Netduino. I mentioned that there are Integrated Circuits (ICs) that may be used for that. In this post I’m going to use one of those ICs (specifically, a 74HCT138) to do the exact same thing. First, here is how it looks: Very simple prototype of the use of a 74HCT138 The code I’m using is exactly the same as before. I have the Encoder class, which will receive a single ......

Posted On Saturday, November 6, 2010 9:02 AM

Magic Transistor Boolean Logic
WARNING: I’m probably doing something terribly wrong here. In my last post, I mentioned that using transistors you can do boolean logic. This is the fundamental basis for computers to work. I wanted to test the concept. In that article, I was using a single Netduino digital output to drive two LEDs. In this experiment, I’m using two digital outputs to drive four LEDs, using some transistors. Here’s the video: Driving 4 LEDs from 2 pins using transistors You can see the LEDs turning on in order when ......

Posted On Wednesday, November 3, 2010 8:58 PM

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