Nuts and Volts - February 2012

#43

Breadboard Part 2: The

Navigator Buttons

by Joe Pardue

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Recap

Last month, we looked at the LCD part of the LCD Navigator project. This month, we will look at the Navigator part: the five momentary pushbuttons arrayed

■ FIGURE 1. LCD Navigator.

as a cross in Figure 1. These buttons can be used to navigate a menu much like you would typically do with a TV remote control five-button navigator as shown in Figure 2. These buttons typically don’t have labels since most folks intuitively know that they are up, down, left, right, and select after just a few moments of messing with them and watching what happens on a TV menu.

We will first look at the hardware considerations for using mechanical switches like these pushbuttons. Then, we will learn to use the nav_button library that you can find in avrtoolbox, buried fairly deeply in the folder tree at avrtoolbox\libavr\source\driver\external_hardware \nav_button. You can get this from the avrtoolbox repository at http://code.google.com/p/avrtoolbox. You will probably want to start with the tester library at avrtoolbox\libavr\testers\nav_buttons.