4.5 Inch Flex Sensor | Hand Gesture Recognition

The 4.5 Inch Flex Sensor is a 1mm thin resistive bend sensor measuring 12cm (4.5 inches) in length, whose internal resistance increases as the sensor is flexed or bent, with a resistance tolerance of ±30% and a rated life cycle of over 1 million flex operations at 3.3V to 5V DC operating voltage. The flex sensor 4.5 inch works similarly to the FSR-402 force sensor in circuit terms — it requires a voltage divider with a fixed resistor to convert the variable resistance into a readable analog voltage for Arduino.

The flex sensor arduino connection places one leg of the flex sensor in series with a fixed resistor (commonly 10kΩ to 47kΩ depending on the flat-state resistance of the specific sensor), with the analog input pin reading the divider midpoint voltage. As the hand gesture sensor bends, resistance increases from its flat-state baseline (typically 25kΩ to 40kΩ) toward several times that value at full bend, and the analog reading shifts correspondingly — straight finger gives one ADC value, fully bent finger gives a higher value, with the relationship requiring per-sensor calibration due to the ±30% tolerance. Per the flex sensor 4.5 inch datasheet, each individual sensor unit has different flat-state and bent-state resistance values, so multi-finger glove projects calibrate each finger sensor separately.

The hand gesture sensor works with Arduino IDE using simple analogRead and a voltage divider resistor. hobbyists building gesture-controlled robots, making data gloves, and makers prototyping wearable input devices use it. Connect the sensor in a voltage divider with a 10kΩ resistor, read the ADC value, and map it to degrees in your sketch. Available from StemVolt, this 4.5-inch flex sensor is ideal for engineering students developing hand gesture recognition, wearable electronics, and motion sensing projects by accurately detecting bending and flexing movements.

Related Products: 

• Checkout the Square Force Pressure Sensor Module

Features:

• Resistance increases proportionally with bend angle for gesture sensing
• 1mm thin 12cm strip mounts along finger or joint surface
• Voltage divider with 10k-47k resistor gives Arduino analog reading
• Over 1 million flex cycles for durable wearable repeated use
• 3.3V to 5V compatible with Arduino ESP32 and STM32 boards

Technical specifications:

 Applications:

• 4.5 Inch Flex Sensor used for Arduino sign language glove build
• College project uses flex sensor 4.5 inch for finger bend detection
• Prosthetic hand uses flex sensor arduino for finger position feedback
• Robot arm uses hand gesture sensor for gesture-controlled joint movement
• Wearable glove uses flex sensor for India SIH gesture project demo

Package includes:

• 1 x 4.5 Inch Flex Sensor