Component Selection

My subsystem is primarily software-oriented, with limited hardware components. As a result, there were few physical sensors or actuators to include in the component selection. For this reason, I listed the push button and LED under the component selection section.

Push Button

  1. TS02-66-50-BK-100-LCR-D -- Push Button

    Pros Cons
    Cheap No Dust Protection
    Good Operating Temperature No Water Protection
    Meets surface mount constraint of project

  2. C&K D6 Series Keyswitch

    Pros Cons
    Cheap More expensive
    Good Operating Temperature Not Water Resistant
    More Tactile/Better Quality

  3. SW-PB11-4CSKG-10 Push Button

    Pros Cons
    Dust Proof Expensive
    Water Proof
    Heavy Duty

Choice: Option 2: C&K D6 Series Keyswitch

Rationale: Since adjacent components in the product also require protection, we must use an enclosure for the entire assembly. This makes the IP67 rating of Option 3 redundant. By using a single enclosure, we can use the higher-quality C&K switch, which offers superior tactile feedback and a much longer 250,000-cycle life, providing better reliability.

Pull Down Resistor

  1. 10K Ohm SMD Resistor

    Pros Cons
    Smaller Form Factor Difficult to Hand Solder
    Moisture Resistant
    Meets surface mount constraint of project

  2. 10K Ohm THT Resistor

    Pros Cons
    Easy to Solder & Prototype Large
    Good Operating Temperature
    Easy to Repair/Replace

Choice: Option 2: 10K Ohm THT Resistor

Rationale: We're using a THT resistor. For a simple RC debounce filter, the miniaturization and high-frequency benefits of SMD are unnecessary, while the durability and ease of soldering of a THT resistor are major advantages for reliability and servicing.

LED

  1. LTST-C170GKT - SMD LED

    Pros Cons
    Cheap Extremely Small
    Wide Viewing Angle SMD

  2. 151051RS11000 - THT LED

    Pros Cons
    THT More expensive
    Highly Visible Fragile

  3. L65DR12L - Pilot Panel Light

    Pros Cons
    Dust Proof Expensive
    Water Proof
    Heavy Duty

Choice: Option 2: 51051RS11000 - THT LED

Rationale: We're selecting Option 2 (THT LED). It avoids the difficult manual soldering of the SMD (Option 1) and the unnecessary cost and complexity of the panel-mount (Option 3). Option 2 is the simplest, most cost-effective choice for our manual assembly process.

LED Resistor

  1. 220 Ohm SMD Resistor

    Pros Cons
    Smaller Form Factor Difficult to Hand Solder
    Moisture Resistant
    Meets surface mount constraint of project

  2. 220 Ohm THT Resistor

    Pros Cons
    Easy to Solder & Prototype Large
    Good Operating Temperature
    Easy to Repair/Replace

Choice: Option 2: 220K Ohm THT Resistor

Rationale: We're using a THT resistor. For a LED Resistor, the miniaturization and high-frequency benefits of SMD are unnecessary, while the durability and ease of soldering of a THT resistor are major advantages for reliability and servicing.

Potentiometer

  1. PDB181-K420K-504A2

    Pros Cons
    easy to use Easy to tamper with
    easy to work with SMD

  2. 3362P-1-103LF

    Pros Cons
    Cheaper Designed for internal use
    designed to hold its setting Fragile

Choice: Option 2: 3362P-1-103LF

Rationale: We're selecting the trimpot, because it mounts internally. This prevents user tampering and ensures the settings remains the same.