rotation-counter.md

Rotation speed with hall sensors

php-pigpio supports measuring rotation speed of hall sensors like A3144, OH3144, AH3144E, TO-92U, etc. This feature is based on notifications.

Setup

Reading/calculation is handled by class RevolutionCounter, which requires a dedicated Notifier instance. For easier setup, static Factory my be used.

Every time a signal is retrieved callback is called with an RotationSpeed object as parameter.

Measuring rotation speed on GPIO pin 22:

use Volantus\Pigpio\HallSensor\Rev\Factory;
use Volantus\Pigpio\HallSensor\Rev\RotationSpeed;

$counter = Factory::create();
$counter->start(22, function (RotationSpeed $speed) {
    echo "Speed: " . round($speed->getRpm()) . " 1/min \n";
});

while (true) {
    $counter->tick(true);
}

Ticks

To retrieve signals $counter->tick() needs to be called. Every time $notifier->tick() is called, it will trigger the given callback with all signals measured since last call to $counter->tick().

Either blocking or non-blocking mode is supported. More details: Notification: Ticks