With stress a proven cause of various illnesses and afflictions various forms of ‘autogenic’ training as a means of relaxation have hit the consumer market. Different types of ‘Bio-feedback’ circuits have also become popular—the idea being that certain physiological functions such as heartbeat, body temperature, and brain activity can be monitored and brought under the conscious control of the patient. The circuit described here operates on the principle of monitoring skin resistance as a measure of how tense you are.
 
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The hardware is an electronic circuit made up of two main parts. The first part is an Arduino shield comprising a type 555 timer IC to generate the input signal for the microcontroller. The second block is built around an Arduino Uno R3 board. It accepts the signal generated by the 555, manipulates it and displays the result on two 7-segment displays interfaced with the microcontroller.