Identify resistance of a resistor using Arduino

High-level Requirements:

• Rq0001: Measure the resistance of the resistor under test

• Rq0002: Measured resistance needs to be displayed on the attached display

• Rq0003: Determine if the resistance measurement is close to expected value

• Rq0004: Determine the measurements using multiple fixed value resistors

• Rq0005: Signal the user by using Buzzer, when the measurement is complete

• Rq1002: Find the optimal time for the measurements

• Rq2001: Warn the user by using Display Notification as well

• Rq2002: Ability to use multiple known resistors to increase the measurement range(preceeds Rq2002)

• Rq3001: Ensure that device doesn't harm user during usage

Requirements Legend:
Rq0... => Functional Requirements
Rq1... => Non-functional Requirements
Rq2... => Nice-to-have Requirements
Rq3... => Regulatory / Legal Requirements

Folder Structure:

.
+-- pictures/
    +-- identifyResistance_bb.png
    +-- identifyResistance_schem.png
    +-- identifyResistance_LCD_I2C_bb.png
    +-- identifyResistance_LCD_I2C_schem.png
    +-- identifyResistance_LCD_Parallel_bb.png
    +-- identifyResistance_LCD_Parallel_schem.png
+-- schematics/
    +-- identifyResistance.fzz
    +-- identifyResistance_LCD_I2C.fzz
    +-- identifyResistance_LCD_Parallel.fzz
+-- src/
    +-- identRes/
        +-- identRes.ino
+-- README.md

Build & Flash:

• Linux in headless mode (no GUI): # arduino --upload src/identRes/identRes.ino --port /dev/ttyACM0
• Linux with GUI: Open arduino software and select board and port Open the project file from the above folder structure Compile and Flash

Note: the serial port might be different, check dmesg after u plug in Arduino to identify the serial port

Required Components:

• Arduino NANO (ATMega328p)
• Display (LCD16x2 with I2C(LCM1602))
• Buzzer
• Multiple Resistors (preferably a set of assorted resistor box)
• Breadboard
• Connecting wires (Jumper cables)

Brief Overview:

• This program's main goal is to display the resistance of the resistor on an LCD Display.
• Added support for using LCD in both Parallel and in Serial(I2C) mode.
• Added support for debugging the program via Serial Interface(UART).
• Buzzer buzzes for a very short interval of time during the Initialization.
• Serial debug can be enabled/disabled in the program by selecting appropriate flag value.
• Delay between two RAW ADC measurements is 100ms.
• Buzzer buzzes for a very short interval of time once the measurement is stabilized.
• When the resistance is out-of-bounds, Display will show 0 Ohm.
• Acceptable resistance range is 100 Ohm to 10KOhm.

Schematics:

LCD with I2C Interface

LCD with Parallel Interface

Breadboard:

LCD with I2C Interface

LCD with Parallel Interface

Measurement Limits

Limits for the measurable resistance values with an optimal accuracy:

• 100 Ohm to 10 KOhm