Week -2

1. Doorbell using Solenoid block

The magnetic activation of the solenoid coil controll the motion of the translation sensor, the displacement of motion solenoidal plung is detected by the motion sensor (which here is assumed to be the arm to ring the bell).

The negergisation of the Solienoidal coil is done using pulse waveform through the switch. the period of the pulse is selected to be 4 sec with 50% duty cycle.

Upon switch activation, Solenoidal coils magnetises and moves the plung inwards, making the initial airgap of 10cm (configurable) zero. this motion is sensed using the motion transaltion sensor.

The Graph shows the input pulse waveform,current though inductor coil and motion sensor respons.

The Small ringings on the sensor waveform on every transistion is controlled by spring constant and dampling value.

2. Thermistor On/OFF

NTC of 1Kohm is being used to sense the heat generated from a source controlled from a signal builder with the inputs provided as per the problem statement.

The drop in the voltage of the thermister as temperature rise above 25deg (298K) is given as the refernce to the comparator switch, which toggels the output controll as scopped out. This output switch toggle can be used as drive signal for the Fan and make it a closed loop system. (and hence Signal builder can be eliminated).

Both, Signal builder and control out put switch signal are plotted here.