Intro to Sensors
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A limit switch is a device that detects the presence, absence, or position of an object by opening or closing an electrical circuit when a physical force is applied to its actuator (like a lever or button).
The Thifty Bot sells a normally closed version of this called the Thrifty Hall Effect, which is a contactless magnet-based limit switch that is omnidirectional with an LED for user feedback. For more info, see the product page
Position Sensing: Detects when the system reaches the end of its range.
Safety: Stops motors if the system they control moves into an unsafe position.
Protection: Prevents parts from moving too far and getting damaged.
Quadrature encoders are sensors that measure the position, speed, and direction of a rotating object using two signals that are 90 degrees apart.
Signal Generation: The rotating shaft produces two square waves.
Direction Detection: The order of the signals shows which way the shaft is turning.
Position Counting: Counts the pulses of the signals to determine position.
Resolution: More pulses per revolution mean more accurate measurements.
Absolute encoders provide a unique position value for each shaft angle, ensuring that the exact position is always known, even after a power cycle.
These encoders use Pulse Width Modulation (PWM) to convey position information. The position is encoded in the width of the pulses generated by the index pin.
Signal Generation: The encoder generates pulses with varying widths corresponding to the shaft's position.
Position Detection: The width of the PWM signal is measured to determine the exact position of the shaft.
Uses:
Precise Positioning: Ideal for applications requiring accurate and repeatable positioning. Think about controlling a swerve module's rotation or an arm's position.
These encoders provide position feedback as a continuous analog signal, typically a voltage or current that varies linearly with the position.
Signal Generation: The encoder produces a continuous analog signal (in the Nova's case, 0-3.3V) proportional to the shaft position.
Position Detection: The control system reads the analog signal to determine the exact position.
Continuous Feedback: Provides smooth and continuous position information.
Precise Positioning: Ideal for applications requiring accurate and repeatable positioning. Think about controlling a swerve module's rotation or an arm's position.
The Thrifty Bot sells one of these, and more info can be found at the product page