How to use a Flex Sensor with Arduino?
A flex sensor is a versatile component used in various applications due to its ability to measure the degree of bending. It essentially acts as a variable resistor, with its resistance changing based on the amount of flex it experiences. This property makes it ideal for applications such as game controllers, data gloves, motion trackers, and biomedical devices.
Pinout of Flex Sensor:
The flex sensor typically has two pins, referred to as P1 and P2. These pins serve as the connection points for retrieving data from the sensor. Unlike some electronic components that have specific polarity, such as LEDs, the flex sensor’s pins are interchangeable. This means that either P1 or P2 can be connected to positive or negative terminals without affecting the sensor’s functionality.
How does it work?
The sensor comes in different sizes, typically 2.2 inches or 4.5 inches long. When the sensor is in a straight position, its resistance is approximately 10 kilohms (KΩ). As it is bent, the resistance increases, reaching a maximum of around 22 KΩ when bent at a 90-degree angle. The construction of a flex sensor involves layers of conductive ink protected by a resin substance. Bending the sensor causes stretching of the conductive layer, resulting in an increase in resistance.
Arduino Flex Sensor
To interface a flex sensor with an Arduino microcontroller, a voltage divider circuit is commonly employed. This circuit consists of the flex sensor and a fixed resistor connected in series. As the flex sensor’s resistance changes with bending, the voltage across it also changes. The Arduino’s analog-to-digital converter (ADC) can then measure this voltage, allowing the microcontroller to interpret the degree of bending.
Here’s a step-by-step guide on interfacing a flex sensor with an Arduino:
Connect the flex sensor and a fixed resistor in series to form a voltage divider circuit.
Connect the output of the voltage divider circuit to one of the Arduino’s analog input pins.
Write code for the Arduino to read the analog input and respond accordingly. This may involve mapping the analog input values to specific actions or outputs.
Example Arduino code for reading a flex sensor might involve:
- Defining the pins used for the flex sensor and any output devices.
- Initializing serial communication for debugging purposes.
- Reading the analog input from the flex sensor using the Arduino’s analogRead() function.
- Calculating the resistance of the flex sensor using the voltage divider formula.
- Mapping the resistance values to control an output device, such as an LED or servo motor.
- Outputting the mapped values and controlling the output device accordingly.
Working of flex sensor module
A flex sensor operates as a variable resistor that changes its resistance in response to bending. When the sensor is straight, its resistance is lower, and it increases as it bends. This change in resistance is proportional to the degree of bending. The sensor’s construction involves a conductive layer that stretches when bent, causing an increase in resistance. By measuring the resistance changes, the sensor can detect and quantify the degree of flexion. Flex sensors are commonly used in various applications, including game controllers, data gloves, and motion trackers, due to their ability to accurately capture bending movements.
Here are some project ideas using a flex sensor:
- Angry Bird Game Controller: Create a game controller using an Arduino and flex sensor to add interactivity to your games.
- Palm Piano: Learn about synthesizers by building a palm piano with a flex sensor for generating tones with finger taps.
- Servo Motor Control using a Flex Sensor: Control the rotation of a servo motor using a flex sensor, or attach the sensor to a glove for finger-controlled motor movements.
- Raspberry Pi Flex Sensor Interface: Interface a flex sensor with a Raspberry Pi using an ADC0804 Analog to Digital Converter and Python programming, ideal for beginners looking to learn about Raspberry Pi and sensor interfacing.
Overall, the flex sensor’s functionality and interface with Arduino provide a simple yet effective way to incorporate bend sensing into various electronic projects.
