What is resistor between force and sense?

 In the case of a force sensing resistor (FSR), the resistor between the force and sense terminals is usually an external resistor connected in series with the FSR. This resistor establishes a voltage divider circuit with the FSR, allowing for the detection of resistance variations caused by applied force.

Here's a brief explanation of how it works:

Voltage Divider Circuit: When a resistor is connected in series with the FSR between the voltage source (usually a supply voltage like 5V) and ground, it creates a voltage divider circuit. The voltage across the FSR (also known as the sense voltage) is determined by the ratio of the FSR's resistance to the total resistance of the FSR and the external resistor.

Voltage Measurement: By measuring the voltage across the FSR using an analog input pin of a microcontroller like Arduino, you can indirectly measure the resistance of the FSR. As the applied force changes the resistance of the FSR, the voltage across it also changes proportionally.

Calibration: The value of the external resistor is chosen based on the expected range of resistance changes of the FSR and the desired sensitivity of the measurement. It's often selected to be in the same order of magnitude as the FSR's resistance at its nominal force condition.

Signal Conditioning: Depending on the specific application, additional signal conditioning circuitry may be used to amplify or filter the sensed voltage signal before it is processed by the microcontroller or other control system.

What is basic force sensing resistor?

A simple force sensing resistor (FSR) is a sensor whose electrical resistance changes in response to applied force or pressure. It is often made up of a sensing substance, such as conductive polymer, embedded on a flexible substrate with electrical contacts on each side. When force is applied to the surface of the FSR, the sensing material compresses or deforms, altering its electrical resistance.

The basic structure of an FSR includes:

Sensing Material: The core component of the FSR is the sensing material, usually a conductive polymer. This material exhibits changes in resistance when subjected to mechanical stress, such as compression or deformation. The conductivity of the material increases as it is compressed, leading to a decrease in resistance.

Substrate: The sensing material is typically embedded within a flexible substrate, which provides support and protection. The substrate allows the FSR to deform or bend in response to applied force without damaging the sensing material.

Electrical Contacts: Electrical contacts are attached to the sensing material on both sides. These contacts allow for the connection of external circuitry, enabling measurement of the FSR's resistance changes.

Basic FSRs are distinguished by their simplicity, versatility, and ease of integration into electronic circuits. They come in a variety of shapes, sizes, and force ranges to suit diverse purposes. Furthermore, they provide benefits like as low cost, durability, and reactivity to dynamic force changes.