got schematics off here to build proton pack lights and after 4 year hey presto they work only thing is instead of counting up to 15 they all come on and then go out one by one counting backwards, went over schematic and can not see anything wrong, anyone know how to correct this so it counts up, i know its back to front but dont know how to put it right, did not use any transistors as leds were used, any help would be great thanx
jimmy
Impossible to help you unless you tell us what schematics you used or post pics of your circuit. At a guess I’d say you forgot to hook up the reset at the end of the cycle so it bounces instead of repeats.
can not believe that you answerd a question for me back in 2007, saying that you have updated YOUR schematics. yes yours, i am so pleased that you answerd, here goes… 2x 4015 1x555 timer have not connected the 4017 or any transistors as i have leds, 4 red leds runing seperate, i have connected pin 14 to pin 2 on the 2nd 4015 and it does run back to pin6 on the same 4015 and to pins 14 and 6 on the first 4015, but i am going to check for a 2nd time to make sure, thanx for answering my question. when i find out how to post a video of the workings i will post also the schematic thanx a million
jimmy
I’m not sure it’s possible to have them light up 1-15 then turn off 15-1 with a 4015 without a microcontroller in the circuit. If you’re saying they light up 1-15 then turn off 1-15 that could be possible but it’d have to be due to power issues. That could be the problem since you say you’re not using transistors. You can’t power the LEDs from the 4015’s, you have to use transistors between them. By the time all 15 lit up you could be exceeding the chip’s functional power output range which will cause some wierd things to happen. The 4015’s aren’t a power source, just a logic source.
no they all light up at once then go out one by one untill there is one left on, then starts the cycle again, also i have a load of CTBC 337-25LE transistors, as i am going to add these to my board now and see if that corrects it, will these transistors be ok i have the 10k resistor to the LED i have orderd 470 ohm resistors off ebay but have 51k resistors can i use these to go to the base of the 337 transistor, or is this not a good idea,?
thanx again jimmy
The 337 is a bit overkill but it should work. A 51k resistor is not a good substitute for a 470 ohm resistor, the values are different by a factor of 100. Unless you read the datasheets and understand how the circuit works you really can’t change the schematic and just toss any old parts in. My guess for why the lights are acting that way is still power issues. The voltage is dropping to the point that the input to the registers is effectively a low signal instead of a high so the chips propigate an off state. It’s wierd that it’d got though a full cycle of on then off but it’s definitely possible depending on how fast you have it running.
thankyou for the information i will stick with the 2N4401 transistors and the 470 resistors i will also stick to the schematic, thanx again for your time in answering my questions. I started with Keith marshalls schematics from jan 2002 but could never get them to work, they would count up to about 10 leds then freez, if i can post the video of these working without the transistors i will, also let you know how i get on,
with regards and thanx
jimmy
well well well guess what!!! yes i have managed to get the power cell to work. you were right about the power, i put 15 blue leds in and the transistors but at first they did not light up i thought it was a solder short as they were only lightening up to number 5 but in order, so i cleaned the tracks with a sharp knife and as i touched number 3 and 4 resistor(10 ohm) it set the whole thing away, i must have a solder short somewhere as i have had to solder a pin from the 3rd resistor to the forth to get the whole thing to work. i know i am only a amature when it comes to schematics but with help from jackdoud i got them to work, if i can manage to build these anyone surely who can read a little schematic drawings can, again thanks for the help, i think i understand the schematic a bit better, using the transistors as a switch??? many many thanx
regards jimmy
Glad you got it working! Yeah, the transistor is essentially an electronic switch that isolates the low power signals coming from the chips from the (relatively) high power that actually lights the LEDs.