CLUTGen CLI

CLUTGen automates the creation of Look-Up Tables for embedded systems, converting raw ADC readings into calibrated physical units such as temperature, pressure, or distance.

Given a set of calibration samples, CLUTGen fits an interpolation curve and generates a production-ready .c/.h pair with the full LUT precomputed for every possible ADC reading.

For Zephyr west module usage, see the zephyr module.

Requirements

• Python 3.10+
• numpy, plotly

Installation

From PyPI:

pip install clutgen

From source:

pip install .

Usage

clutgen [OPTIONS] input_files...

Interpolation method (mutually exclusive, default: --linear):

Examples:

# Explore interpolation methods interactively before choosing
clutgen --preview ./calibration/temperature.toml ./calibration/pressure.toml

# Generate with splines after exploring
clutgen --splines ./calibration/temperature.toml ./calibration/pressure.toml

# Custom output directory and file name
clutgen -o ./src/generated -n sensor_luts ./calibration/temperature.toml

TOML Configuration

Each sensor requires a TOML configuration file and a CSV with its calibration samples.

CSV schema:

raw,calibration

Where raw is the ADC reading and calibration is the expected output value at that reading.

TOML schema:

name = "temp_sensor"                # C identifier — used as <n>_lut in generated code
description = "ambient temperature" # Used in Doxygen comments and plot titles
table_resolution_bits = 12          # ADC resolution in bits (e.g., 12 → 4096 entries)
lut_type = "int16_t"                # C type for the generated array

samples_csv = "./data/temperature_samples.csv"  # Relative to this file, or absolute

# Optional
interpolation = "polynomial"        # Overrides the CLI interpolation method for this LUT

Interpolation Methods

Output

For each run, CLUTGen produces two files:

• <name>.h — extern declarations with Doxygen comments, safe to include anywhere in the project
• <name>.c — full LUT definitions, compiled once and linked

Each configured sensor produces an array named <n>_lut, where n is the name field from the TOML:

#include "lookup_tables.h"

int val = temp_sensor_lut[adc_reading];

Preview

Opens an interactive figure in the browser showing all interpolation methods overlaid for each configured sensor. Use this to explore and compare methods before committing to one in the TOML.

When multiple sensors are configured, a dropdown allows switching between them:

You can focus on selected interpolations, zoom into regions, and hover over the plot to compare methods and make a confident choice: