This document provides information about a student group project to design a stress meter circuit. It includes: 1) An introduction to the presenters and topic of measuring stress levels. 2) Background information on what causes changes in skin resistance during stress and relaxation. 3) A description of the components used in the circuit including resistors, capacitors, an IC, LEDs, and sensors to measure skin resistance. 4) An explanation of how the circuit works to indicate different stress levels through the lighting of LEDs controlled by the IC. 5) Potential applications for using this stress meter and advantages of the portable low-power design.

1. MINI PROJECT GROUP ASSIGNMENT
PRESENTATION
TOPIC-STRESS METER
PRESENTERS:- TAMCHI WADIE
SUMAN DEV
DIGVIJAY BHATTACHARJEE

2. STRESS
 Stress is a physiological condition in which
the body becomes excited to face an
emergency situation.
 Increase in heart rate, breathing rate etc
occurs during a high stress state.
 A permanent stress condition is harmful to
the body and may results in many health
problems.
 The circuit described here is useful to
monitor the stress level before and after
practicing a relaxation exercise.

4. PRINCIPLE
 The resistance of the skin varies, if the stress
level is high the skin offers less resistance and if
the body is relaxed the skin resistance is high.
During high stress there is increase in the blood
supply to the skin, this increases the permeability
of the skin.
 High stress causes sweating and leakage of
water from the blood vessels in the skin. This
makes the skin moist and electrical conductivity
increases.

5. CIRCUIT

6. COMPONENETS
 Resistors: 1)R1- 470Ω
2)R2- 1.2 K
3)R3- 470Ω
4)R4- 470Ω
5)R5- 1K
6)R6- 47Ω
7)VR1- 1M
8)VR2- 47K
 Capacitors: 1)C1- 10µ, 16V
2)C2- 100µ, 16V
3)C3- 100µ, 16V

7.  Semiconductor: 1) IC1- LM3915
2) T1- BC548
3) D1- IN4148
4) ZD1- 5.1V,0.5W
5)Red, Green and Blue LED
 PZ1- Piezo Buzzer
 9V Battery
 One Way Switch
 Touch Pads

8. LM3915
 It is a monolithic integrated circuit that
senses analogue voltage levels and
displays them through LEDs providing
a logarithmic analogue display. It can
drive up to ten LEDs one by one for
each increment of 125 mV in the input.

9. PIN CONFIGURATION

11. PIEZO BUZZER

12. APPLICATIONS
 Stress level indicator.
 For measuring resistance of skin.
 To know mental state of person.
 In diagnosis of excessive sweating
(Hyperhydroses).

13. ADVANTAGES
 Portable.
 Low power consumption.
 Low cost.
 Highly sensitive to small currents.

14. DISADVANTAGES
 Less accuracy.
 Output is not measurable.

15. THANK YOU