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Small Can Be Better: Applying Modern Computer Technology to Layout Operations ... Continued

By Russ Keil,  TCA 04-56974                           Return to Main Article

For those interested in considering further technical aspects of this effort, we present additional information below. Learning such things takes time and effort. If you have questions, feel free to contact me.

First, a quick overview of some standard Arduino components:

Arduino components.
Typical Arduino Components

Note that these are SMALL, and require careful handling. The nomenclature for Arduino class items calls any add-on board a "shield."

MEGA board

The Arduino UNO R3 uses an Atmel ATmega328P chip, which is an 8-bit RISC processor with 32 x 8 General Purpose registers and up to 20 MIPS (million instructions per second) throughput @ 20MHz. It has 32K of programmable Flash Memory, used for Program Storage, 1K of EEPROM and 2K of internal SRAM. It also has two 8-bit and one 16-bit counters, a real-time counter and programmable serial UART.  There are 14 Digital Input/Output (I/O) pins (of which 6 can be used as PWM outputs) and 6 analog inputs. PWM is an acronym for Pulse Width Modulation and is used to control motor speeds, robotic servos and the intensity of LEDs and lights, similar to the way a light dimmer works. There is also a 16 MHz crystal oscillator, a USB connection, a power jack, an in-circuit serial programming header (ICSP) and a reset button. Click here for the more information.

The Arduino MEGA seen above is a microcontroller based on the Atmel ATmega2560 chip instead of the ATmega328P found on the UNO R3. The Mega has 54 digital (I/O) pins, (of which 14 can be used as PWM pins) and 16 Analog Input pins. This board also features 256K of flash memory, 8K of SRAM and 4K of EEPROM. It also has 4 hardware UARTS for communication. There is a 16 MHz crystal oscillator, a USB connection, a power jack, an in-circuit serial programming header (ICSP) and a reset button. It also supports I2C (TWI) and SPI communication.  Click here for the complete datasheet.

The UNO can operate at 3.3V or 5V while the MEGA operates at 5V. Both have a recommended input voltage of 7-12V (DC). They can be powered via the USB connection or with an external power supply of the appropriate DC voltage. Non-USB power can come either from an AC-DC adapter (think wall-wart) or battery using a 2.1mm center-positive plug inserted into the board's power jack.

Gabe schematic

Note that the above diagram is a "breadboard" view of Gabe's components. The breadboard allows the designer to test the components (using Dupont wires with pins attached to each end, making it easy to plug into the Arduino & breadboard holes), before final assembly and soldering the finished project. Click image for larger view of both Breadboard and Daughter Board versions.

The Air Whistle controller on the previous page made use of a daughter board (these are also known as shields). The shield allows projects to be more modular, so that changing components can be done without having to solder wires and components. I use these shields as often as possible. They add less than $2 to a project, and make it a lot easier to work with the board after installation.


Relays as seen above are used throughout projects as needed.

Continue to next page for more illustrations and technical information


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