Police Lights
- Thread starter Admin
- Start date
Hello Admin,
I have looked at the vid. for this circuit and compared it to the schematic. It doesn't seem to correspond. I wonder if you could explain the pin selection on the schematic for the 4017 ic. I understand that pin 3 of the 555 goes to pin 14 on the 4017 and that EN and R are pins 13 and 15 that go to ground but the other pins on the 4017 seem to be confusing, to me anyway. What is pin 0 and why are the other pins on the 4017 selected as they are? The outputs are pins 1-7 and 8,9,10. Pin 16 is the positive supply but is not shown on the schematic. Pin 8 is ground but is not shown as such. HELP!
Konrad
I have looked at the vid. for this circuit and compared it to the schematic. It doesn't seem to correspond. I wonder if you could explain the pin selection on the schematic for the 4017 ic. I understand that pin 3 of the 555 goes to pin 14 on the 4017 and that EN and R are pins 13 and 15 that go to ground but the other pins on the 4017 seem to be confusing, to me anyway. What is pin 0 and why are the other pins on the 4017 selected as they are? The outputs are pins 1-7 and 8,9,10. Pin 16 is the positive supply but is not shown on the schematic. Pin 8 is ground but is not shown as such. HELP!
Konrad
The numbers are the outputs not the pin numbers. Also to get the counter to count properly you need to ground all the unused outputs and put a 100nf capacitor across the supply.
I tried this circuit and couldn't get it to work, I then found a similar one with resistors on the outputs instead of the diodes and once I'd grounded the unused outputs it works great. I have 8 (2 x 4 in series with 39 ohm resistor) very bright LEDs on each side and its megga. I'll see if I can get a link for the schematic.
I tried this circuit and couldn't get it to work, I then found a similar one with resistors on the outputs instead of the diodes and once I'd grounded the unused outputs it works great. I have 8 (2 x 4 in series with 39 ohm resistor) very bright LEDs on each side and its megga. I'll see if I can get a link for the schematic.
Hello guys, I have not have any luck getting this thing to work. After completing my circuit fallowing the video tutorial nothing happens and 4017 start to over heat almost instantly. After numerous checking for errors I could not find any. After checking with circuit diagram on the web I find that 4017 does not show connection to positive via pin 16 VDD at all but in the video it is. Bit confused there.... Anyways, ill give it another try with "police circuit 2 " motioned here tomorrow . Regardless, the video should be updated with connection details and schematics need some clean up also.
!CORRECTION! 10/8/2013
It works just fine. Now that I understand how 4017 works I got it working just fine. I took my time to update the schematics with all the pins connected and output labels for better understanding. BTW any of these three transistors will work for this project : BC547, 2N3904 or NTE 123AP
!CORRECTION! 10/8/2013
It works just fine. Now that I understand how 4017 works I got it working just fine. I took my time to update the schematics with all the pins connected and output labels for better understanding. BTW any of these three transistors will work for this project : BC547, 2N3904 or NTE 123AP
Pin 16 goes to the +9v supply. If the chip gets hot there's a problem that end, forget the output transistors for the minute.
I made a wee logic probe with a 3mm red LED, resistor and piece of wire. You can check the 555 is pulsing properly with this.
Don't forget to ground all unused outputs on the 4017 chip and fit a 100nf capacitor across the supply, mine was flashing randomly before I did this.
I made a wee logic probe with a 3mm red LED, resistor and piece of wire. You can check the 555 is pulsing properly with this.
Don't forget to ground all unused outputs on the 4017 chip and fit a 100nf capacitor across the supply, mine was flashing randomly before I did this.
Yes Fleck, "Police Lights-2" Worked on first try with your modification of grounding. Plugged it into 12volt DC power adapter and had to add 0.1uF cap across supply like you recommended. Finished the speed of strobe to my liking with 3.3uF cap instead 2.2uF and added 2.4K resistor to 22K on the 555. Running with 8 LEDs 4 red and 4 blue
Again thanx for help
Here is little video I just made
parts used:
1x 555 timer
1x CD4017
2x NTE123AP transistors
2x IN4148 diodes
18x 470 ohm resistors
1x 24.4K resistor ( in my case 1x 22K + 1x 2.4K )
1x electrolytic 3.3uF cap
1x ceramic 0.1uF cap
8x LED - In my case 4 blue 4 red 5mm 2.2-2.8 volt 100mA each ( very bright!)
Again thanx for help
Here is little video I just made
parts used:
1x 555 timer
1x CD4017
2x NTE123AP transistors
2x IN4148 diodes
18x 470 ohm resistors
1x 24.4K resistor ( in my case 1x 22K + 1x 2.4K )
1x electrolytic 3.3uF cap
1x ceramic 0.1uF cap
8x LED - In my case 4 blue 4 red 5mm 2.2-2.8 volt 100mA each ( very bright!)