1. IC 555
ThinkLABS
www.thinklabs.in

2. IC 555 : “The IC Time Machine”
 Multipurpose timer IC
 Designed and built in 1971
 Still widely used, with over
1billion units sold
worldwide
 Cheap, Stable, Easy to use
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3. IC 555: Applications
 Operating modes
 Monostable
 Astable
 Bistable
 Non-traditional applications
 Buffer
 NOT Gate
 Comparator
 Schmitt Trigger
 many more…
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4. IC 555: Monostable Mode
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5. IC 555: Monostable Mode
 One shot multivibrator
 Formula:
 T = 1.1 x R1 x C1
Example:
R1 = 10K
C1 = 100uF
T = 1.1 seconds
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6. IC 555 Monostable
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7. IC 555 Monostable + Clap
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8. IC 555: Clap activated Robot
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9. IC 555: Turn when clapped
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10. ACTIVITY
 Use the 555 Timer IC to periodically ON - OFF the LED.
Without Touching the Circuit!!
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11. IC 555: Astable Multivibrator
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12. IC 555: Astable Multivibrator
f = 1/(.693 x C1 x (R1 + 2 x R2))
Example:
R1 = 10K
R2 = 10k
C1 = 100uF
F = ~ 0.48 Hz
T= ~ 2 sec
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13. IC 555: Astable Multivibrator
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14. BACK TO SENSORS
Proximity Sensing
 Can we use the line sensors to detect objects??
 How do we remove the Ambient Light??
 Mechanical Filter
 Electronic Filter
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15. Modulated Sensor
Obstacle
IR RX
IR
Transmitter Receiver
Signal Generator Signal
Filtering
(LM555 oscillator) Conditioning
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16. Sensors (TSOP 1738)
 Used as remote control
receivers in TV, Music
players, etc..
 Available for 30Khz to
56Khz carriers
 Immune to ambient light
 Output is active low and
toggles between 0 to 5V
 Easy to use
 Very Sensitive
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17. Modulating using IC 555
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18. Modulated Sensor
IR LED I/P
TSOP O/P
GND
Vcc
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19. OBSTACLE AVOIDER
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