Flex Sensor Circuit Design

The flex sensor also a variable resistor but the resistance of this sensor changes according to the bending flexing.

Flex sensor circuit design.

In this tutorial we will learn how to make and use a flex sensor we will control servo motor with a flex sensor flex sensors are passive resistive devices that can be used to detect bending or flexing. Before we get to circuit building and arduino programming here s a quick rundown of the flex sensor s important electrical characteristics. The flex sensor circuit we will build is shown below. The flex sensor shown in this tutorial is a fl.

Design tips ics power ics analog ics digital ics passive. Flex circuits can be shaped to fit where no other design and round wire exhibiting benefits of each. For our circuit we create a voltage divider between the flex sensor and a fixed resistor. Here we will replace the variable resistance rv1 with flex sensor.

Flex sensor are used to resistive carbon materials like a graphite. A flex sensor has a range from about 10k to 35k that means it won t give us a full 0 5 volt range or 0 1023 analog value. Flex sensor working details. This sensor doesn t contain any polarized terminal such as diode otherwise capacitor which means there is no positive negative terminal the required voltage of this sensor to activate the sensor ranges from 3 3v 5v dc which can be gained from any.

It is a two terminal device and the terminals are like p1 p2. Read analog value from flex sensor value analogread. A single flex circuit. So this sensor resistance increases depends on surface linearity.

The flex sensor can be used for servo motor control intensity control or you can use where ever the resistance need to be changed when the bending occurs. Flex sensor is a basically a variable resistor whose terminal resistance increases when the sensor is bent. In this flex sensor are many applications human machine interfaces and robotics medical automotive. When the sensor is straight the particles give the ink a resistance.

Wiring harness space and weight reduction. The pin configuration of the flex sensor is shown below. Since the flex sensor has a flat resistance of 25kω and a bend resistance of 45kω to 125kω we want a fixed resistor that has a value between these 2 resistance values the flat and the bend. In essence flex circuits give you unlimited freedom of packaging geometry while retaining the precision density and repeatability of printed circuits.

One side of the sensor is printed with a polymer ink that has conductive particles embedded in it. It supposed to be between 700 to 900. Vo being output voltage and also the voltage across the flex sensor. It contains carbon on a strip of plastic to act like a variable resistor.

Try to use the serial monitor below to find out what analog value you will take while you bending the sensor. Flex sensor is a completely linear it will be having its nominal resistance. Here the circuit constructed with arduino and. The circuit will be as below.