Challenge: STEMTera Analog Inputs and Potentiometers

ECE 206: STEMTera and Potentiometer
Challenge: STEMTera Analog Inputs and Potentiometers
In this lab, we will learn an alternative approach to change the LED display numbers; a potentiometer
will be used instead of a quadrature encoder to adjust the displayed numbers.
A potentiometer is a three-way resistor that can output different resistance by adjusting a built-in screw
or knob. It also acts as a voltage divider since there are essentially two resistors in series with common
node connected to the middle pin and each end of the resistors connected to the side pin of a
potentiometer (see Figure 1).
Figure 1. Circuit diagram of a potentiometer
In this lab, you will rebuild the circuit you used in Lab 3.1 and replace the quadrature encoder with the
potentiometer. Connect one side pin of a potentiometer to 5 V, the other side pin to GND, and the
middle pin to an analog input pin of the STEMTera board. This way, the voltage received at the middle
pin can change from 0 to 5 V due to the voltage divider rule.
Next, you will use the Arduino code to convert the received analog value to an integer variable ranging
from 0 to 99 and display it on the LED display segment.
Once your circuit can display numbers from 0 to 99 using a potentiometer, demonstrate it to your TA.
Both potentiometers and encoders are commonly used to enter data into a digital system. Compare the
advantages and disadvantages of each device. Under what circumstances might you prefer one versus
the other?
Report Deliverables:
• Include a diagram/sketch of you circuit.
• Include commented code for your design.
• Obtain your TA signoff on the circuit in operation
Updated 10/2/2020
Report should contain, at minimum the following elements:
• Title, Names, Dates
• Statement of Purpose
• Plan and Execution
• Results / Conclusion
o Answer any questions posed in the lab challenge.
o Explain your understanding of what happened and why.
Report Element Value
Documentation of lab completion 40
Circuit diagram 20
Commented code 20
Report quality and all other elements 20
Maximum possible score 100/100