Project 3: Introduction to Electronics: The Basics

Description Introduction to electronics:
Learn about the concepts of electricity, voltage and current through the water analogy
Hook up a simple circuit using a solderless breadboard that lights up an LED

Materials RaspberrySTEM™ Base with Raspberry Pi
RaspberrySTEM™ CREATOR Lid
LED RaspberrySTEM™ Cell
Buttons RaspberrySTEM™ Cell



Prerequisites Introduction to the RaspberrySTEM™
What is electricity?
  • Flow of charged particles (in this curriculum, we are generally concerned with the flow of electrons through a conductor (a metal, usually copper)).
  • Water analogy – Flow of water through a completely filled pipe is highly similar (in intuitive basis and in equations) for many of the electrical concepts. Many electronics components can be modeled with analogous water based structures that are intuitively easy to understand. A brief list of concepts about electricity in a wire can be explained by analogy to water in a pipe:
Electricity Water
Current – flow of electrons Current – flow of water molecules
Voltage Pressure
Resistance Constriction
Battery or Voltage Source Pump
  • Ubiquity – electricity is everywhere, and used to power all of our modern devices: to heat our homes, run electronics, and turn motors.
  • What is a Circuit?
  • Definition: A loop (of wire) that conducts electricity
  • Simplest circuit: power source (e.g. battery) connected to a load (e.g. light bulb).
  • Saftey
Demonstration: LED throwie (with resistor) – one of the simplest circuits
  • Build the circuit as shown, using your hands. This can be done by pinching one lead of the the resistor and one lead of the LED around the battery with the left hand, and pinch the remaining LED and resistor leads together with the right hand.
  • Note: Current will only flow through the LED in one direction, therefore you must connect it up correctly (no harm done if you don't, but it won't work). The cathode of the LED (has the shorter lead, and has a flat side) should be connected to the negative side of the battery.
  • Note: An LED throwie can be made without the resistor, however it is considered bad practice to do so as it either it can possibly damage either the battery or LED (the resistor is used to limit the current through the circuit to a reasonable level). But, as the LED throwies are often only temporarily, they are often made without the resistor. In this exercise, though, it makes sense to teach the proper way to connect up an LED.
How Does a Breadboard Work?
  • Contains metal clips inside that make it easy to connect wires together.
  • Has power rows marked in blue and red on the top and bottom edges.
  • All other holes are connected together as columns of 5.
Assemble the RaspberrySTEM™ CREATOR Lid
  • Attach the Connector PCB to to the Lid with two nuts and bolts. The bolts should be pointed upwards.
  • Attach the CREATOR Lid to the Raspberry Pi with the ribbon cable.
  • Snap the Lid onto the RaspberrySTEM™ Base.
Building Your First Circuit on a Breadboard
  • Connect the 3.3V power and ground (GND) from the CREATOR Lid Connector to the breadboard power rails. The 3.3V should be hooked up to the positive “+” (red) rail, and the GND should be hooked up to the negative “-” (blue) rail.
  • Build the circuit as shown in the previous example, in two steps:
    • First, plug the resistor/LED connection into a single 5-pin column of the breadboard (previously held with the right hand). Continue to hold the left hand with the battery. The LED should light up.
    • Second, remove the battery and instead hook the leads that were connected to the battery to the positive and negative. The LED should light up.