Source: http://www.aaroncake.net/
I don't know why, but people like blinking lights. You see LED chasers everywhere, in TV shows (Knight Rider), movies, and store windows. This schematic is my version of a simple 10 LED chaser. There is no 555 timer used because at my local electronics store they are over $4 Cdn. Instead, an oscillator made up of two sections of a 4011 NAND gate is employed. This chip is very inexpensive and extremely common.
Part |
Total Qty. |
Description |
Substitutions |
R1 |
1 |
1 Meg 1/4W Resistor |
|
R2 |
1 |
100K Pot |
|
R3 |
1 |
1K 1/4W Resistor |
220Ohm if using blue LEDs |
C1 |
1 |
0.1uF 16V Ceramic Disk Capacitor |
|
U1 |
1 |
4011 CMOS NAND Gate |
|
U2 |
1 |
4017 CMOS Counter |
|
LED1-10 |
10 |
LEDs Of Any Colour |
|
MISC |
1 |
Board, Sockets For ICs, Knob For R2 |
1. Use R2 to adjust the "chase rate".
2. You may need to use a lower value resistor if you wish to use blue LEDs. Try 220 Ohm.
3. You can also use incandescent lamps instead of LEDs. Use transistors to drive them by connecting the base of the transistors to each of the outputs of the 4017 through a 1K resistor. Connect one end of the lamp to the positive supply. Then connect the other end to the collector of the transistor. The emitter then goes to ground. Depending on the lamps, you may need power transistors that are heat sinked.
4. C1 may be replaced with a larger value for a slower "chase rate".
5. If you have problems with weird circuit behavior, try replacing R1 with a 33K resistor, and increasing C1 to 1uF.
6. If you plan to use this circuit in your car, be warned that in some areas it is illegal to have red, blue or yellow flashing lights unless you are an emergency vehicle.
titus 2015-05-13 19:27:15 I tried this circuit and it worked well. Could you kindly help me with an led display circuit that can make letters come on may for 2minutes and then off for 8seconds and the then continuously. Hoping to hear from you soon. Best regards, Titus. [Reply] [Reply with quote] |
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Glenn OKeefe 2014-07-31 03:13:04 I've never put something like this together. I was wondering if you could explain or direct me to an explanation of the non-sequential CD4017 "outs" for the LED's. The pins on the 4017 are numbered 1 -16. I am confused over the 11,9,6,5,1, etc. The pin configuration 1-8 down one side & 9-16 up the other side. So in the schematic above how is #11 in pin #16 place and #9 in pin #15 place, #6 in pin #14 place and so on? Could you possibly explain this to me. I sure would appreciate it. Thank you very much, Glenn [Reply] [Reply with quote] |
+27
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