3.3V-5V Flexible Bend Sensor with Analog Output Module

Description

The 3.3V-5V Flexible Bend Sensor Module is a resistive bend-sensing assembly designed to convert physical bending into a readable analog voltage. Unlike a bare flex sensor, this module includes an onboard voltage divider circuit, so the sensor’s variable resistance is converted to a voltage that can be read directly by any microcontroller ADC pin (such as Arduino, ESP32, or Raspberry Pi with an external ADC).

The sensor element itself is a thin, flexible strip coated with conductive ink. When the sensor is straight, its resistance is at a baseline value (typically ~10KΩ for the 4.5″ variant, with some tolerance) . When bent toward the side with the printed text, the resistance increases significantly—up to 60KΩ–110KΩ at 90° bend for the pre-soldered module variant . The onboard circuitry translates this resistance change into an analog voltage output.

The module operates from 3.3V to 5V DC, making it compatible with both logic levels. The analog output (AO) provides a continuous voltage proportional to the bend angle. Some variants also include a digital output (DO) with an onboard potentiometer, allowing a threshold to be set so the DO pin switches HIGH/LOW when the bend exceeds a specific angle—useful for triggering alarms or relays without writing complex threshold code .

Critical limitations: The sensor is directional—it must only be bent toward the side with the printed text. Bending it backward yields unreliable data and can permanently damage the internal carbon traces . The resistance-to-angle relationship is non-linear, and individual sensors vary (tolerance ±30%), so per-sensor calibration is required for meaningful angle measurements . The sensor base where it meets the PCB is a mechanical weak point—do not bend sharply at the base .

Features

• Onboard Voltage Divider: Converts the flex sensor’s variable resistance to an analog voltage, eliminating external resistor wiring .

• Analog Output (AO): Continuous voltage proportional to bend angle, readable by any microcontroller ADC.

• Digital Output (DO) with Potentiometer (some variants): Adjustable threshold for simple bend-triggered switching without code .

• Wide Supply Compatibility (3.3V–5V): Works with Arduino, ESP32, and other 3.3V/5V systems .

• Reinforced Base (pre-soldered module): The sensor is soldered to a PCB with heat-shrink reinforcement, addressing the fragile-pin issue of bare flex sensors .

• Thin and Flexible Sensing Element: Suitable for wearable and finger-mounted applications.

• Long Life Cycle: Rated for over 1 million bends under proper use .

• Directional Sensing: Reliable data only when bent toward the printed side.

Technical Specifications