Page 199 - Make Your Own PCBs with EAGLE from Schematic Designs to Finished Boards

FIGURE 8-1 An Arduino Uno.

The board has two rows of sockets on either side, and a wide range of plug-in shields are
available that are the same size as the Arduino board but fit over the top of it and add extra features.
Among other things, there are shields for Ethernet interfacing, controlling motors, and various kinds
of displays.

Shield Design

When designing a shield, before wading into the schematic design, it is usually a good idea to think
about exactly what the shield will do. In this case, we could set down the design goals of the shield as
follows:

• A top shield; that is, no shields stacked on top of it

• Attractive design with retro four-digit, seven-segment display
• Real-time clock (RTC) chip

• Buzzer