Potentiometer and LED Board

Goal: Make a board with an LED and potentiometer

TinkerCAD

To better understand the circuit that we were going to create on a protoboard, we used TinkerCAD to simulate our boards. First, we made a board with an LED that could be turned on with a slide switch. We learned that the middle leg was critical for supplying power to the switch, and since it had two remaining legs, one LED could be turned on when the switch is in the first position. The second LED could be turned on when the switch was in the second position.

The LED on the right is on

The LED on the left is on

Note the different positions of the slide switch; in one, the switch is in the "up" position, and in the other, it's in the "down" position.

Once accustomed to using TinkerCAD for simulating circuits, we used TinkerCAD to plan our protoboards. These boards would include a potentiometer, a slide switch, and an LED. We learned that a potentiometer is like a customizable resistor, where the resistance can be changed.

The potentiometer is set to its lowest resistance, which is not enough for the LED. So, it blows the LED.

The potentiometer is set to have more resistance, so the LED can light up without being blown.

The potentiometer has the most resistance possible, which leads to a dimmer LED.

Making the protoboard

We used solder, wires, and the necessary components (LED, potentiometer, and slide switch) to replicate what we made on TinkerCAD in real life.

My protoboard

We soldered (through hole soldering) the components onto the board. I was unable to finish creating solder bridges to connect the components and where the power/ground would be coming from.

Learning how to use EAGLE

We used Eagle by Autodesk to learn how to learn how to make a schematic, following these instructions:

An Overview of Schematic Basics

Following the tutorials in the above tutorials, I generally did not have any trouble creating the final result. However, there are steps that are critical to follow, including:

  • Activation of libraries- you cannot input any components into a schematic without access to the libraries
  • Performance of an action on any component, such as rotation or movement- To rotate a component, first select the rotation tool. Then, select the component you would like to rotate. The move tool works similarly. Many CAD programs function differently (where you select the object and then the tool), but Eagle functions differently.
  • Use of nets instead of wires
  • Understanding junctions versus overlaps- a "node" (or a dot at the intersection of two nets) indicates that these nets are connected. To add a junction to an existing net, click on the intersection again while still in the net tool or use the junction tool.
  • Use of ERC- ERC is a useful tool that helps prevent mistakes when actually milling the board. Use the errors in the ERC as a checklist of things to correct.