System Design

Before we get into the nitty-gritty of theory and components we want you to think about design in general. Electronics are just a means to an end. Every circuit has a few common features that you should think about prior to putting down a single resistor or jumper wire. You can change your mind later as you experiment, but you should try to consider the overall design from the beginning.

Output

What is the purpose of the circuit—what is being controlled? Are you turning a heater on/off, are you spinning something with a motor? Or maybe you are making an artistic design with flashing lights or sounds?

Power Source

What could power this circuit? Is AC power from the wall possible? Does a battery work? How long will the battery last at expected currents?

— A power source can be a wall outlet, a battery or even an Arduino Microcontroller

There are several power pins on an Arduino Microcontroller, including “5V” and “GND”(abbreviation for “ground”). 5V is the pin supplies 5 volts of power to your projects, which a common value for digital electronics. There are a few ground pins on the Arduino and they all work the same.

User Control

What user inputs do you want? These could be simple buttons, a dial, or even a keyboard and mouse. Some designs may not even need user input and rely purely on sensors.

Sensors

What sensory inputs are required for the circuit to operate? Do you need to monitor temperature, light, or distance? Some designs may not even need sensors.