Monday, December 7, 2015
A Bedside Lamp Timer Circuit
A Bedside Lamp Timer Circuit - 30 minutes operation, Blinking LED signals 6 a minutes ago before turn-off.
The reason for this circuit is to control a light or other apparatus for a given time (30 minutes for this situation), and afterward to turn it off. It is helpful when perusing at bed by night, killing the bedside light naturally in the event that the peruser nods off.. After turn-on by P1 pushbutton, the LED lights up for around 25 minutes, yet then it begins to squint for two minutes, quits flickering for two minutes and flickers for another two just before exchanging the light off, subsequently flagging that the on-time is consummation. In the event that the client need to draw out the understanding, he/she can acquire another half-hour of light by pushing on P1. Killing the light at clients simplicity is acquired by pushing on P2.
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| A Bedside Lamp Timer Circuit |
Circuit operation:
Q1 and Q2 structure an ALL-ON ALL-OFF circuit that in the off state draws no huge current. P1 begins the circuit, the hand-off is turned on and the two ICs are controlled. The light is controlled by the transfer switch, and IC2 is reset with a positive voltage at pin 12. IC2 begins wavering at a recurrence set by R4 and C4. With the qualities appeared, pin 3 goes high after around 30 minutes, killing the circuit by means of C3. Amid the c6 minutes going before turn-off.
The LED does a flickering activity by associations of IC1 to sticks 1, 2 and 15 of IC2. Squinting recurrence is given by IC2 oscillator at pin 9. The two entryways of IC1 are wired in parallel to source more present. On the off chance that required, a piezo sounder can be associated with pins 1 and 14 of IC1. Clearly, timings can be differed changing C4 and/or R4 values.
Q1 and Q2 structure an ALL-ON ALL-OFF circuit that in the off state draws no huge current. P1 begins the circuit, the hand-off is turned on and the two ICs are controlled. The light is controlled by the transfer switch, and IC2 is reset with a positive voltage at pin 12. IC2 begins wavering at a recurrence set by R4 and C4. With the qualities appeared, pin 3 goes high after around 30 minutes, killing the circuit by means of C3. Amid the c6 minutes going before turn-off.
The LED does a flickering activity by associations of IC1 to sticks 1, 2 and 15 of IC2. Squinting recurrence is given by IC2 oscillator at pin 9. The two entryways of IC1 are wired in parallel to source more present. On the off chance that required, a piezo sounder can be associated with pins 1 and 14 of IC1. Clearly, timings can be differed changing C4 and/or R4 values.
Parts:
Resistors
R1 = 1K
R2 = 4K7
R3 = 10M
R4 = 1M
R5 = 10K
Capacitors
C1 = 470µF-25V
C2-C4100nF-63V
Semiconductors
C1 = 470µF-25V
C2-C4 = 100nF-63V
D1-D4 = 1N4002
D5 = 5mm. Red LED
IC1 = CD4012
IC2 = CD4060
Q1 = BC328
Q2 = BC547
Miscellaneous
P1,P2 = SPST Pushbuttons
T1 = 9+9 Volt Secondary 1VA Mains transformer
RL1 = 10.5V 470 Ohm Relay with SPDT 2A 220V switch
PL1 = Male Mains plug
SK1 = Female Mains socket
Resistors
R1 = 1K
R2 = 4K7
R3 = 10M
R4 = 1M
R5 = 10K
Capacitors
C1 = 470µF-25V
C2-C4100nF-63V
Semiconductors
C1 = 470µF-25V
C2-C4 = 100nF-63V
D1-D4 = 1N4002
D5 = 5mm. Red LED
IC1 = CD4012
IC2 = CD4060
Q1 = BC328
Q2 = BC547
Miscellaneous
P1,P2 = SPST Pushbuttons
T1 = 9+9 Volt Secondary 1VA Mains transformer
RL1 = 10.5V 470 Ohm Relay with SPDT 2A 220V switch
PL1 = Male Mains plug
SK1 = Female Mains socket
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