Flex Sensor Circuit Design

A single flex circuit.

Flex sensor circuit design.

In essence flex circuits give you unlimited freedom of packaging geometry while retaining the precision density and repeatability of printed circuits. When the sensor is straight the particles give the ink a resistance. The circuit will be as below. It is a two terminal device and the terminals are like p1 p2.

The flex sensor shown in this tutorial is a fl. Here we will replace the variable resistance rv1 with flex sensor. So this sensor resistance increases depends on surface linearity. The flex sensor also a variable resistor but the resistance of this sensor changes according to the bending flexing.

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. Flex sensor is a basically a variable resistor whose terminal resistance increases when the sensor is bent. Here the circuit constructed with arduino and. Flex sensor working details.

Flex circuits can be shaped to fit where no other design and round wire exhibiting benefits of each. Flex sensor are used to resistive carbon materials like a graphite. Flex sensor is a completely linear it will be having its nominal resistance. Arduino make a flex sensor for robotic hand cheap and simple.

For our circuit we create a voltage divider between the flex sensor and a fixed resistor. It contains carbon on a strip of plastic to act like a variable resistor. The pin configuration of the flex sensor is shown below. Design tips ics power ics analog ics digital ics passive.

It supposed to be between 700 to 900. 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. 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. Wiring harness space and weight reduction.

So it is usually used to sense the changes in linearity. 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. Read analog value from flex sensor value analogread. The flex sensor circuit we will build is shown below.

As shown in figure r1 here is a constant resistance and flex sensor which acts as a variable resistance. Try to use the serial monitor below to find out what analog value you will take while you bending the sensor. 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. Before we get to circuit building and arduino programming here s a quick rundown of the flex sensor s important electrical characteristics.