The stress meter provides us with an electronic representation of the emotional suffering that we are experiencing. One is able to determine the amount of stress that the body is experiencing with the assistance of this equipment. A warning beep will sound in addition to the stress meter providing a visual indicator through a Light Emitting Diode (LED) display in the event that the stress level is extremely high. The device is little enough to be worn on the wrist like a watch.

The operation of the device is predicated on the hypothesis that changes in emotional state are accompanied by shifts in the resistance of the skin. When there is a high amount of stress, the skin's resistance is decreased, and when the body is relaxed, the skin's resistance is increased. The increase in blood supply to the skin at times of extreme stress is the cause of the decreased resistance that the skin exhibits. Because of this, the permeability of the skin is increased, which in turn enhances its ability to conduct electric current. This characteristic of the skin is utilized here in order to determine the level of stress. The stress meter's touch pads are responsible for sensing the voltage fluctuations that occur across the touch pads and communicating this information to the circuit. The circuit has a high degree of sensitivity and can detect even a slight change in voltage when applied to the touch pads. An explanation of the Stress Meter's Circuit Signal amplification and analogue display components are both included in this circuit. Variations in voltage that are produced by the sensing pads are amplified by the transistor BC548 (T1), which is set up to function as a common-emitter amplifier. By resistor R1, one of the touch pads is linked to the base of T1, which is also connected to the ground rail through potmeter VR1. Adjusting the amount of sensitivity of T1 to

the level that is required can be done by adjusting VR1. Diode D1 ensures that transistor T1 has the correct biasing, while capacitor C1 ensures that the voltage at the emitter of T1 remains constant. Through variable resistor 2, the signal that has been amplified by transistor T1 is sent to the input of integrated circuit LM3915 (IC1). The IC LM3915 is a monolithic integrated circuit that senses analogue voltage levels at its pin 5 and displays them through LEDs to provide a logarithmic analogue display. It does this by reading the voltage levels in the opposite direction. In the dot/bar mode, it may individually power up to 10 LEDs at a time for each 125 mV step in the input voltage. In this case, we simply made use of five LEDs, which were attached to IC1's pins 14 through 18. When input pin 5 of IC1 receives 150 mV, LED1 will light up and shine. When the voltage reaches 650 mV, LED5 begins to illuminate, and when the degree of stress is high, LED5 begins to flash, and piezobuzzer PZ1 begins to beep. The flashing elements are formed by the resistors R4 and R5, as well as the capacitor C2. The current through the LED is kept at around 20 mA by the resistor R3. In order for the integrated circuit to work correctly, capacitor C3 needs to be positioned in close proximity to pin 3. The circuit receives a regulated 5V from the Zener diode ZD1, which is connected in series with the resistor R6.