Arduino : Since the first edition of this book, there have been many new developments in the Arduino product line (a lot from other vendors as well); there are many flavors of the “Arduino” out in the wild. For the purposes of this book, the MEGA 2560 Pro will be used. This is because it has a very small form factor, and it has a ton of IO (inputs/outputs). Really though as we are designing through this book, you may want to experiment with other Arduino boards; that is fine and encouraged since most of the code in this book will work with the standard Arduino UNO form factor; that is not to say other form factors will not work as well. See Figure 1-1.

Bluetooth Mate Silver or RN-42: Since this book will focus on end to end development while still keeping in mind the engineering process to prototype your circuit, you may want to purchase a Bluetooth Mate Silver, but when we design actual PCBs (Printed Circuit Boards), we will need to use a module that we can quickly and effectively use just like the Bluetooth Mate Silver, which is the RN-42. This module has a small footprint which will be nice because we want to use as little space on the PCB as possible. See Figure 1-2.

Solderless breadboard: Another very important piece of hardware is the solderless breadboard (see Figure 1-3), which is used to implement your circuitry. For this book, you need to have a midsize solderless breadboard. It will be used in both the design and troubleshooting phases of the projects and will allow you to create a proof of concept for when we create the PCB in Eagle.

Wire: We will use a large quantity of wire in this book; you can get a wire jumper kit at almost any electronics store.

Arduino shields : Unlike the first edition of this book, we will not focus too much on shields; they are very useful and can make validating firmware a breeze, but this edition will focus on creating a couple of shields for the MEGA 2560 Pro. See Figure 1-4 for a couple of examples of shields, and underneath that picture, you will find a few descriptions of useful shields for this book. Please note that it is not necessary to purchase these shields, but they are still valuable tools.

Motor shield: This shield is used to control motors up to 18V. It includes a surface mount H-bridge, which allows for a higher power motor to be used as well as for control of two motors.

GPS shield: This shield is used to get positioning information from GPS satellites. It uses the National Marine Electronics Association (NMEA) standard, which can be parsed to tell you any number of things such as longitude and latitude, whether the GPS has a fix, what type of fix, a timestamp, and the signal-to-noise ratio.

Sensors: These are very important because they give your projects life. Some sensor examples are PIR (Passive Infrared), sonar, and temperature (see Figure 1-5).

PIR sensor: This is an outstanding sensor for detecting changes in infrared light and can detect changes in temperature. It is also great at detecting motion, and that’s what we will use it for.

Sonar sensor (not pictured): Sonar sensors are good at detecting objects in their surroundings. The sonar sensor we will use is a Parallax sensor that uses digital pinging to tell how far away an object is.

Temperature sensor: These sensors are used to read temperature. To use them, you first scale the voltage to the temperatures you want to record.

Accelerometer: This sensor can detect acceleration in multiple directions, that is, in the X, Y, and Z directions. There are accelerometers that have more degrees of freedom. These sensors can be used to measure motion, vibration, or shock. For example, accelerometers are used in Fitbits and other exercise tracking hardware to keep track of your step count or even what exercise you are doing. We will be using an accelerometer later in this book on the main shield that we will create.

GPS module: The GPS module that will be used in this book is the EM-506; it has a UART interface which will make it very easy to interface with the Arduino.

Photoresistor: These sensors are used to sense brightness and dimness.

Tilt sensor: This sensor is used to detect if a system has flipped over which can be useful if you don’t have access to an accelerometer.

Flex sensor: As this sensor is flexed, the resistance increases, which can then be read by the Arduino on one of its ADCs (Analog to Digital Converters) to keep track of how much flex a system has.

Humidity sensor: The RHT03 humidity sensor can read both temperature and relative humidity and is accurate (+/–2%RH for humidity and +/–0.5C for temperature) for a low-cost sensor.

FSR (force sensitive resistor): This sensor is great to detect force. A good use for this sensor may be a scale or to detect pressure points.

Servos and motors: We will be using motors and servos to control many aspects of the projects (see Figure 1-6).

Miscellaneous: These are the most common components, such as resistors, capacitors, LEDs, diodes, headers, push buttons, and transistors. You can buy many kits that will supply you for a while on all this hardware at a low cost (see Figure 1-7).

Soldering iron: This tool is used to connect circuits to each other; we will use it mostly to connect wire to circuits (see Figure 1-8).

Solder: You will use this in conjunction with the soldering iron; it is the metal that connects the circuits together. Solder has a very low melting point.

Needle-nose pliers: These pliers are very important; they are used to hold wire and circuits in place, wrap wire around circuitry, and so on.

*Third hand: This is a very useful tool when you are trying to solder a PCB together (see Figure 1-12 #2).

Cutters : These are used to cut wires (see Figure 1-12 #1).

Wire stripper: This tool is used to take off wire insulation (see Figure 1-12 #3).

Multimeter: Possibly the most important tool you can own; this tool allows you to read voltage (AC (alternate current) and DC (direct current)), amps (ampere), and ohms (see Figure 1-10).

*Scientific calculator: This allows you to do various calculations (Ohm’s law, voltage divider, etc.).

*Adjustable DC power supply: With a power supply, you can give your projects continuous power; this is normally only used for testing circuits (see Figure 1-9).

*Microscope: Can be very useful for checking leads on circuits to make sure they are soldered properly (see Figure 1-11).

*Logic analyzer: Another very useful tool; a logic analyzer will read back data coming off of various IO lines. For example, the one pictured in Figure 1-13 #1 can read eight lines of IO simultaneously; these IO lines could be UART, I2C, SPI, and so on. We will discuss these protocols later in this book.

*AVR programmer (AVRISP mkII): This programmer can be used to upload code into various Atmel uC (microcontrollers). It is also able to upload the Arduino Bootloader onto the ATMEGA2560 or ATMEGA328p.

*FTDI programmer: Another programmer, if the board you are working on does not have an ISP (in-system programmer), it may have a five-pin header that you can connect an FTDI programmer to. Make sure you get the correct voltage level FTDI programmer for your system. Normally, they come in 5V and 3.3V levels (see Figure 1-14).

*Oscilloscope : The multimeter and the oscilloscope are probably the most important tools when debugging electronics. The Oscope, as it is sometimes referred to as, allows you to measure voltage vs. time. This can be useful when reading back digital or analog signals. For example, you may want to read the output of a digital pin to make sure it is triggering at the correct intervals. This is an example where a multimeter would not be as useful as an Oscope because the Oscope will show you voltage over time (such as transitions from high to low states) for a set interval, and the multimeter will just display the latest voltage output.