Motor speed controller


Posted on Nov 2, 2012

During summer nights, the temperature is initially quite high. As time passes, the temperature starts dropping. Also, after a person falls asleep, the metabolic rate of one's body decreases. Thus, initially the fan/cooler needs to be run at full speed. As time passes, one has to get up again and again to adjust the speed of the fan or the cooler.The device presented here makes the fan run at full speed for a predetermined time. The speed is decreased to medium after some time, and to slow later on. After a period of about eight hours, the fan/cooler is switched off.Fig. 1 shows the circuit diagram of the system. IC1 (555) is used as an astable multivibrator to generate clock pulses.


Motor speed controller
Click here to download the full size of the above Circuit.

The pulses are fed to decade dividers/counters formed by IC2 and IC3. These ICs act as divide-by-10 and divide-by-9 counters, respectively. The values of capacitor C1 and resistors R1 and R2 are so adjusted that the final output of IC3 goes high after about eight hours.The first two outputs of IC3 (Q0 and Q1) are connected (ORed) via diodes D1 and D2 to the base of transistor T1. Initially output Q0 is high and therefore relay RL1 is energised. It remains energised when Q1 becomes high. The method of connecting the gadget to the fan/cooler is given in Figs 3 and 4.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

White LED Drive Circuit
LCD Car Accelerometer
Sonar-transducer-switch
Power Buffer Boosts Reference Current
Getting started with AVR development
USB Powered Stereo PC Multimedia Speaker
PIC Controlled Relay Driver
Simple Lightning Detector Circuit
Dual Relay Driver Board Circuit Schematic
PIC16F688 Digital Voltmeter
Audio Mixer
FPGA DC Motor Control Circuit
Transcranial magnetic stimulation
Low-power FM transmitter circuit diagram 1000M range
Dual-phase power switchover circuit schematic



Top