Utility helpers for Arduino / ESP32: PID controller, timing helpers, circular buffer, etc.

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• Source: https://github.com/mathieucarbou/MycilaUtilities
• Examples: examples/
• API headers: src/
• Classes reference: docs/CLASSES.md

This repository includes a few focused utility classes. See docs/CLASSES.md for the full short reference; the main types are:

• Mycila::PID — flexible PID controller with modes, anti-windup, json export (optional), pause/resume and reset.
• Mycila::CircularBuffer<T,N> — small fixed-size numeric circular buffer with rolling stats (avg/sum/min/max).
• Mycila::ExpiringValue<T> — value container with expiration semantics and optional JSON export.
• Mycila::string — string helper utilities (trim, case conversion, formatting floats).
• Mycila::Time — helpers for formatting Unix timestamps, converting HH:MM, and time-range checks.

A compact and flexible PID controller. Key features:

• Configurable Kp, Ki, Kd and tunings
• Proportional and derivative modes (ON_ERROR or ON_INPUT)
• Integral correction modes (OFF or CLAMP)
• Output limits and optional anti-windup
• Reverse mode, time-sampling mode, pause/resume, and reset with optional initial output
• State getters (pTerm/iTerm/dTerm/last input/output) and optional JSON export when MYCILA_JSON_SUPPORT is enabled

PID Simulator available in examples/PIDSimulator:

• video link
• PID Simulator Web version

Full PID controller documentation is available at https://mathieu.carbou.me/MycilaUtilities/pid

A fixed-size circular buffer specialized for numeric types (integers and floating point).

• O(1) add and rolling statistics: count, sum, avg, min, max, first/last, diff, rate
• Useful for smoothing, moving averages, and small-window metrics

Holds a value with an optional expiration time (milliseconds).

• Update the value and obtain the old value
• Check presence/expiration and retrieve the value or an alternative
• Optional JSON export when MYCILA_JSON_SUPPORT is enabled

Small string helper utilities:

• toLowerCase / toUpperCase
• trim, startsWith, endsWith
• to_string(float,double,decimals)

Time helpers:

• Format Unix timestamps to ISO8601 or local strings
• Convert HH:MM to minutes and check if a time is in a range
• Format seconds into D HH:MM:SS

If you'd like, I can expand this page with example snippets, code references, or copy parts of header comments into the docs.

See examples/ for demonstrations and working sketches, including a PID simulator and web UI examples.

Contributions are welcome — please follow the CODE_OF_CONDUCT.md and open PRs against main.

MIT