Crate pamoja_kit 

Goal-named helper math for the pamoja SDK.

The hardest part of building something real on a cheap sensor is rarely reading the sensor; it is turning that reading into a decision that holds up in the field. pamoja-kit is the layer that closes that gap for people who are not signal-processing engineers. Each helper is named for the goal rather than the technique, ships with correct defaults, and documents the real algorithm one layer down, so it teaches as it abstracts.

The first helpers cover the jobs the cookbook leans on most:

• Smoother - smooth a noisy reading (exponential moving average).
• Kalman - settle to a steady value from a noisy sensor (one-dimensional Kalman).
• Complementary - fuse a fast rate with a slow absolute reading (complementary filter).
• Median - reject spikes with a rolling median (robust to a lone bad reading).
• Debounce - clean a chattering on/off signal into one event (counter debounce).
• Calibration - turn a raw reading into real units (two-point linear map).
• deadband - ignore small wiggle around a setpoint so an actuator does not chatter.
• Thermostat - keep a reading near a setpoint (on/off control with hysteresis).
• Pid - hold a value at a target with a smooth, proportional command (PID control).
• Ramp - ease a command toward a target at a limited rate (slew-rate limiter).
• Depletion - warn before a falling level runs out (linear extrapolation).
• Surge - warn when a reading changes dangerously fast (first difference).
• Trend - tell whether a value is rising or falling and how fast (least-squares slope).
• Anomaly - flag a reading that departs from its recent history (three-sigma rule).
• Window - keep a rolling window of recent readings and read their spread (min, max, range, mean, population variance).
• units - convert a reading to the unit a person reads (Celsius and Fahrenheit, pascals to hPa/kPa/psi, ratio and percent).
• DiffDrive, Ackermann, SkidSteer, Mecanum - wheel kinematics for the common differential, car-like, skid-steer, and omnidirectional chassis (behind robotics).
• TwoLinkArm / forward_kinematics - manipulator kinematics: the planar two-link inverse, and Denavit-Hartenberg forward kinematics for any serial arm.
• Odometry - dead-reckon a Pose from a body motion or wheel deltas, exact-arc.
• WaypointFollower / obstacle_stop - steer toward a waypoint and stop for an obstacle (behind robotics and geo).
• SafetyGate - the gate every motion command passes through: emergency EStop, deadman Watchdog, and bounded motion (Limits).
• ServoMap / Esc / Quadrature / QuadratureScale - servo and ESC pulse widths and quadrature-encoder decoding.
• Twist / Pose - the shared body-velocity and world-pose types the robotics helpers use.
• Coordinate / Geofence - great-circle distance and bearing, and leaving a safe area (behind the default geo feature).
• imu - roll and pitch from a three-axis accelerometer (behind the imu feature).
• weather - the dew point from temperature and humidity (behind the weather feature).

The geo, imu, weather, and robotics features each pull in libm for no_std float math and can be turned off on the most constrained targets; the waypoint guidance needs both robotics and geo.

The crate is no_std and allocation-free, so the same helpers run on a microcontroller and on a server.

Examples

Compose two helpers to hold a noisy fridge probe near 4 C:

use pamoja_kit::{Smoother, Thermostat};

let mut probe = Smoother::new(0.5);
let mut fridge = Thermostat::cooling(4.0, 0.5);

// A warm, noisy reading is smoothed, then drives the cooler on.
let cooler_on = fridge.update(probe.update(7.8));
assert!(cooler_on);

Modules

imu

Tilt from a three-axis accelerometer.

units

Converting readings between real-world units.

weather

Humidity-derived values: the dew point.

Structs

Ackermann

Car-like (Ackermann) steering: one steered axle and a driven axle a wheelbase apart.

Anomaly

Flags a reading that lies far from the recent norm.

Calibration

A linear map from raw sensor counts to calibrated units.

Complementary

Blends a drifting rate measurement with a noisy absolute one into a steady estimate.

Coordinate

A position on the Earth, in decimal degrees.

Debounce

Cleans a noisy boolean signal by requiring it to hold steady before reporting a change.

Depletion

Predicts how soon a falling level will reach a threshold.

DhParameters

The four Denavit-Hartenberg parameters describing one joint-to-joint step of a serial arm.

DiffDrive

Converts between a robot’s motion and its two wheel speeds (differential drive).

EStop

An emergency stop that latches: once engaged it holds until explicitly reset.

Esc

Maps a normalized throttle to an electronic speed controller’s RC pulse width.

Geofence

Keeping a tracked point inside an area, and noticing when it leaves.

Guidance

The steering command toward a waypoint, with the geometry behind it.

Kalman

Estimates a steady value from noisy readings with a one-dimensional Kalman filter.

Limits

Bounds a robot’s speed and acceleration so commands stay within what the machine can do safely.

Mecanum

Mecanum (four-wheel omnidirectional) drive: forward, sideways, and turning at once.

Median

A median filter over the most recent N readings.

Odometry

Tracks a robot’s Pose by accumulating its motion over time (odometry).

Pid

Drives a measured value to a target by blending proportional, integral, and derivative terms.

Pose

A planar pose in the world frame: position and heading.

Quadrature

Decodes a quadrature (A/B) encoder into a running tick count.

QuadratureScale

Converts encoder ticks into the distance and speed a wheel has travelled.

Ramp

Moves a value toward a target by at most a fixed step each update.

SafetyGate

The single gate every motion command passes through, composing e-stop, watchdog, and limits.

ServoMap

Maps a servo angle to its RC pulse width in microseconds, and back.

SkidSteer

Skid-steer (tracked or four-wheel) drive: turning by spinning each side at a different speed.

Smoother

Smooths a noisy signal with an exponential moving average.

Surge

Warns when a reading changes faster than a safe rate.

Thermostat

A hysteresis (bang-bang) controller for a single on/off actuator.

Transform

A 4x4 homogeneous transform: a rotation and a translation in one matrix.

Trend

Tracks the linear trend of the most recent N readings.

Twist

A planar body velocity: the command a wheeled robot is driven with.

TwoLinkArm

A planar two-link arm: the textbook arm with a closed-form inverse.

Watchdog

A deadman timer: it expires unless fed often enough, catching a stalled controller or link.

WaypointFollower

Guides a robot from waypoint to waypoint by GPS-style coordinates (carrot following).

WheelSpeeds

The four wheel speeds of a mecanum or omni base, front and rear, left and right.

Window

A fixed-capacity window over the most recent N readings.

Enums

Boundary

Where a fix sits relative to a Geofence, including the moment it crosses.

Elbow

Which way a two-link arm’s elbow bends; both reach the same point.

Functions

deadband

Holds a reading at a center value while it stays within a band, ignoring small wiggle.

forward_kinematics

Returns the transform from the base to the tool for a serial arm of DH joints.

obstacle_stop

Stops forward motion when an obstacle is within the stopping distance, leaving turning free.