How can you ensure code remains safe when sensors fail?

• A. Implement fault detection, safe defaults, and fallback routines.
• B. Remove fault detection to simplify code.
• C. Ignore sensor failures and continue.
• D. Power cycle repeatedly until it works.

Answer: (A)

Graceful degradation through fault detection, safe defaults, and fallback routines is how you keep code safe when sensors fail. Build the system to notice when sensor data looks wrong, stale, or outside plausible ranges, and to respond before anything unsafe happens. Fault detection might check data freshness, range validity, cross-checks with other sensors, or sanity checks on the rate of change. When a fault is detected, switch to safe defaults—values that you know are safe, or a defensive mode that limits actions to non-risky behavior. Fallback routines provide a plan for operating under degraded conditions, such as using an alternate sensor, relying on a trustworthy estimate, or reducing performance to a safe level until the primary sensor is healthy again. The goal is to prevent acting on uncertain data and to ensure the system can either recover safely or enter a known safe state.

Ignoring fault detection or continuing with bad data would lead to unpredictable and potentially dangerous behavior. Merely power cycling to make the issue go away is not a reliable or safe strategy; it’s a temporary workaround that doesn’t address the underlying risk or provide a controlled response when failures occur.