LED Dominos Using a 555 Timer -- The Learning Circuit 63

Matt — Tue, 26 Nov 2019 17:29:22 GMT

Current Revision posted to Documents by Matt on 11/26/2019 5:29:22 PM

LED Dominos Using a 555 Timer

The Learning Circuit | element14 presents | Project Videos

www.youtube.com/watch

In the last lesson, we learned what happens inside a 555 timer to make it work. In today’s episode, Karen uses 555 timers to make LED “dominos”. Each unit has an LED connected to the output of a 555 timer and an LDR attached to the trigger. When the LDR senses light, the 555 is triggered turning the light on for a brief period of time. When multiple units are placed in a row, each one triggers the next. The duration that each light is on is determined by an “RC circuit” made of a resistor and capacitor. Changing their values can change the duration that the light is on.

The idea for this project came from a video made by Randy Elwin back in 2011. Karen uses his idea to make a similar device to show off using a 555 timer in a monostable circuit. (Learn more about monostable circuits in the NEXT lesson about 555 timers.) Shining a light on the LDR triggers Pin 2 and the 555 is “set” on. The RC circuit connected to pins 6 & 7 eventually cause the voltage at Pin 6 to go High enough to reset the 555, turning the LED off.

Bill of Material:

Product Name	Manufacturer	Quantity	Buy KitBuy Kit
Electrolytic Capacitor, Miniature, 100 µF, 50 V, HE Series, ± 20%, Radial Leaded, 8 mm	nichicon	1	Buy NowBuy Now
Ceramic Disc Capacitor, 0.01 µF, 100 V, ± 20%, 5 mm	Vishay	1	Buy NowBuy Now
LM555CN - Timer, Oscillator & Pulse Generator IC, TTL Compatible, Astable, Monostable, 4.5 V to 16 V, DIP-8	On Semiconductor	1	Buy NowBuy Now
Through Hole Resistor, 220 ohm, 400 mW, ± 1%	Vishay	1	Buy NowBuy Now
Through Hole Resistor, 10 kohm, 250 mW, ± 1%	TE Connectivity	2	Buy NowBuy Now
Photo Resistor	Adafruit	1	Buy NowBuy Now
Prototype Board, 25 x 15 grid, 1.6 mm, 72 mm, 47 mm	Multicomp	1	Buy NowBuy Now
LED, Cool White, Through Hole, T-1 3/4 (5mm), 20 mA, 3.2 V	Cree	1	Buy NowBuy Now
9V battery snap, flexible	Multicomp	1	Buy NowBuy Now
Battery, 9 V, PP3, Alkaline, 565 mAh	Pro Elec	1	Buy NowBuy Now
Hook-up Wire Spool Set - 22AWG Solid Core - 10 x 25ft	Adafruit	1	Buy NowBuy Now

Tags: 9v battery snap, tlc, hook-up wire spool set, e14presents_karencorbeill, e14presents_makerkaren, through hole resistor, ceramic disc capacitor, ldr, prototype board, dominos, 555 timer, led, photo resistor, 555 timers, electrolytic capacitor, 555

The Learning Circuit: 63: LED Dominos Using a 555 Timer

kellyhensen — Thu, 14 Jul 2022 13:53:17 GMT

Revision 2 posted to Documents by kellyhensen on 7/14/2022 1:53:17 PM

LED Dominos Using a 555 Timer

The Learning Circuit | element14 presents | Project Videos

www.youtube.com/watch

Bill of Material:

Product Name	Manufacturer	Quantity	Buy KitBuy Kit
Electrolytic Capacitor, Miniature, 100 µF, 50 V, HE Series, ± 20%, Radial Leaded, 8 mm	nichicon	1	Buy NowBuy Now
Ceramic Disc Capacitor, 0.01 µF, 100 V, ± 20%, 5 mm	Vishay	1	Buy NowBuy Now
LM555CN - Timer, Oscillator & Pulse Generator IC, TTL Compatible, Astable, Monostable, 4.5 V to 16 V, DIP-8	On Semiconductor	1	Buy NowBuy Now
Through Hole Resistor, 220 ohm, 400 mW, ± 1%	Vishay	1	Buy NowBuy Now
Through Hole Resistor, 10 kohm, 250 mW, ± 1%	TE Connectivity	2	Buy NowBuy Now
Photo Resistor	Adafruit	1	Buy NowBuy Now
Prototype Board, 25 x 15 grid, 1.6 mm, 72 mm, 47 mm	Multicomp	1	Buy NowBuy Now
LED, Cool White, Through Hole, T-1 3/4 (5mm), 20 mA, 3.2 V	Cree	1	Buy NowBuy Now
9V battery snap, flexible	Multicomp	1	Buy NowBuy Now
Battery, 9 V, PP3, Alkaline, 565 mAh	Pro Elec	1	Buy NowBuy Now
Hook-up Wire Spool Set - 22AWG Solid Core - 10 x 25ft	Adafruit	1	Buy NowBuy Now

The Learning Circuit: 63: LED Dominos Using a 555 Timer

tariq.ahmad — Wed, 29 Jan 2020 14:42:11 GMT

Revision 1 posted to Documents by tariq.ahmad on 1/29/2020 2:42:11 PM

LED Dominos Using a 555 Timer

The Learning Circuit | element14 presents | Project Videos

www.youtube.com/watch

Bill of Material:

Product Name	Manufacturer	Quantity	Buy KitBuy Kit
Electrolytic Capacitor, Miniature, 100 µF, 50 V, HE Series, ± 20%, Radial Leaded, 8 mm	nichicon	1	Buy NowBuy Now
Ceramic Disc Capacitor, 0.01 µF, 100 V, ± 20%, 5 mm	Vishay	1	Buy NowBuy Now
LM555CN - Timer, Oscillator & Pulse Generator IC, TTL Compatible, Astable, Monostable, 4.5 V to 16 V, DIP-8	On Semiconductor	1	Buy NowBuy Now
Through Hole Resistor, 220 ohm, 400 mW, ± 1%	Vishay	1	Buy NowBuy Now
Through Hole Resistor, 10 kohm, 250 mW, ± 1%	TE Connectivity	2	Buy NowBuy Now
Photo Resistor	Adafruit	1	Buy NowBuy Now
Prototype Board, 25 x 15 grid, 1.6 mm, 72 mm, 47 mm	Multicomp	1	Buy NowBuy Now
LED, Cool White, Through Hole, T-1 3/4 (5mm), 20 mA, 3.2 V	Cree	1	Buy NowBuy Now
9V battery snap, flexible	Multicomp	1	Buy NowBuy Now
Battery, 9 V, PP3, Alkaline, 565 mAh	Pro Elec	1	Buy NowBuy Now
Hook-up Wire Spool Set - 22AWG Solid Core - 10 x 25ft	Adafruit	1	Buy NowBuy Now