21-06-2011, 11:43 AM
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Chapter: 1 Introduction
While actually giving in to our body’s natural wants such as sleep, we’re keeping the balance beam in an upright and neutral position — generally a good thing to do. But life comes and calls quite often, many times forcing us to put hunger, drowsiness, and other basic human needs on the back burner in order to seal the deal and get the job done.
So here’s the scenario, you’re sitting in your car getting ready for a big meeting that if completed will net your company nice little multi-billion dollar deal. You’re supposed to be going over your notes and preparing yourself for this staple achievement. But instead, you find yourself doing the whole bobble head thing, getting dangerously to the steering wheel with each and every bob. If only there were something to keep you awake…
This circuit saves both time and electricity for students. It helps to prevent them from dozing off while studying, by sounding a beep at a fixed time interval, say, 30 minutes.
If the student is awake during the beep, he can reset the circuit to beep in the next 30 minutes. If the timer is not reset during this time, it means the student is in deep sleep or not in the room, and the circuit switches off the light and fan in the room, thus preventing the wastage of electricity.
Students: Maybe they forgot the exam was tomorrow, maybe they were out partying, or maybe they just waited until the last minute. In any case, college students always have the need to burn the midnight oil. The problem is that it is extremely easy to fall asleep in the midst of studying and before you know it, morning has come and the exam is already over or you still haven't learned the material. If you don't want that to happen, then keep this reliable anti sleep alarm at your side.
Chapter: 2 Circuit descriptions
This circuit saves both time and electricity for students. It helps to prevent them from dozing off while studying, by sounding a beep at a fixed time interval, say, 30 minutes.
If the student is awake during the beep, he can reset the circuit to beep in the next 30 minutes. If the timer is not reset during this time, it means the student is in deep sleep or not in the room, and the circuit switches off the light and fan in the room, thus preventing the wastage of electricity
2.1 Circuitry
2.2 Things Needed for Making this Antisleep Alarm
• Relay
• Bulb
• Transistor or SCR
• Push to ON /OFF switches
• Resistance & capacitor
• Pizzo buzzer
• Diode
• IC: IC CD4020
The circuit is built around Schmitt trigger NAND gate IC CD4093 (IC1), timer IC CD4020 (IC2), transistors BC547, relay RL1 and buzzer. The Schmitt-trigger NAND gate (IC1) is configured as an astable multivibrator to generate clock for the timer (IC2). The time period can be calculated as T=1.38×R×C. If R=R1+VR1=15 kilo-ohms and C=C2=10 μF, you’ll get ‘T’ as 0.21 second. Timer IC CD4020 (IC2) is a 14-stage ripple counter.
Around half an hour after the reset of IC1, transistors T1, T2 and T3 drive the buzzer to sound an intermediate beep. If IC2 is not reset through S1 at that time, around one minute later the output of gate N4 goes high and transistor T4 conducts. As the output of gate N4 is connected to the clock input (pin 10) of IC2 through diode D3, further counting stops and relay RL1 energies to deactivate all the appliances. This state changes only when IC1 is reset by pressing switch S1.
Assemble the circuit on a general-purpose PCB and enclose it in a suitable
cabinet. Mount switch S1 and the buzzer on the front panel and the relay
at the back side of the box. Place the 12V battery in the cabinet for powering
the circuit. In place of the battery, you can also use a 12V DC adaptor.
Chapter: 1 Introduction
While actually giving in to our body’s natural wants such as sleep, we’re keeping the balance beam in an upright and neutral position — generally a good thing to do. But life comes and calls quite often, many times forcing us to put hunger, drowsiness, and other basic human needs on the back burner in order to seal the deal and get the job done.
So here’s the scenario, you’re sitting in your car getting ready for a big meeting that if completed will net your company nice little multi-billion dollar deal. You’re supposed to be going over your notes and preparing yourself for this staple achievement. But instead, you find yourself doing the whole bobble head thing, getting dangerously to the steering wheel with each and every bob. If only there were something to keep you awake…
This circuit saves both time and electricity for students. It helps to prevent them from dozing off while studying, by sounding a beep at a fixed time interval, say, 30 minutes.
If the student is awake during the beep, he can reset the circuit to beep in the next 30 minutes. If the timer is not reset during this time, it means the student is in deep sleep or not in the room, and the circuit switches off the light and fan in the room, thus preventing the wastage of electricity.
Students: Maybe they forgot the exam was tomorrow, maybe they were out partying, or maybe they just waited until the last minute. In any case, college students always have the need to burn the midnight oil. The problem is that it is extremely easy to fall asleep in the midst of studying and before you know it, morning has come and the exam is already over or you still haven't learned the material. If you don't want that to happen, then keep this reliable anti sleep alarm at your side.
Chapter: 2 Circuit descriptions
This circuit saves both time and electricity for students. It helps to prevent them from dozing off while studying, by sounding a beep at a fixed time interval, say, 30 minutes.
If the student is awake during the beep, he can reset the circuit to beep in the next 30 minutes. If the timer is not reset during this time, it means the student is in deep sleep or not in the room, and the circuit switches off the light and fan in the room, thus preventing the wastage of electricity
2.1 Circuitry
2.2 Things Needed for Making this Antisleep Alarm
• Relay
• Bulb
• Transistor or SCR
• Push to ON /OFF switches
• Resistance & capacitor
• Pizzo buzzer
• Diode
• IC: IC CD4020
The circuit is built around Schmitt trigger NAND gate IC CD4093 (IC1), timer IC CD4020 (IC2), transistors BC547, relay RL1 and buzzer. The Schmitt-trigger NAND gate (IC1) is configured as an astable multivibrator to generate clock for the timer (IC2). The time period can be calculated as T=1.38×R×C. If R=R1+VR1=15 kilo-ohms and C=C2=10 μF, you’ll get ‘T’ as 0.21 second. Timer IC CD4020 (IC2) is a 14-stage ripple counter.
Around half an hour after the reset of IC1, transistors T1, T2 and T3 drive the buzzer to sound an intermediate beep. If IC2 is not reset through S1 at that time, around one minute later the output of gate N4 goes high and transistor T4 conducts. As the output of gate N4 is connected to the clock input (pin 10) of IC2 through diode D3, further counting stops and relay RL1 energies to deactivate all the appliances. This state changes only when IC1 is reset by pressing switch S1.
Assemble the circuit on a general-purpose PCB and enclose it in a suitable
cabinet. Mount switch S1 and the buzzer on the front panel and the relay
at the back side of the box. Place the 12V battery in the cabinet for powering
the circuit. In place of the battery, you can also use a 12V DC adaptor.
