I have built a LED circuit that cycles 4 led’s with the push of a button. I am using a CD4017 and triggering it with a LM555. When I trigger the LM555 (pin 2) with a pushbutton the output is sent to the CLK of the CD4017. This causes it to advance one light. I have built 24 of these and they are located throughout the shop. This works fairly well so I took it a step further. I made a Master box that sits in the office. It has 24 sets of 4 LED’s that represent what is displayed on the small boxes. From each small box I send the same signal that I use to trigger the first CD4017 and have it trigger a duplicate CD4017 circuit. The lights will change at the same time . The problem that I am having is that the master box LED’s will change sometimes by themselves. I must be getting a stray signal from somewhere. Can I put a filter in the circuit? Any suggestions?
If you use only the CMOS and the 555 you mentioned, it would be good to have more than 5v supply, 9 or 12 would be better for the I2R loses. Also, a question. Have you add a pull up resistor?
post a schematic so that we can see what you have built...we wont b scared of it!!!...also are u edge triggering yr 555?if u have a pushbutton connected so you ground pin 2 -as u release yr pushbutton u will have switch bounce which will cause unpredictable results regarding triggering and how long are the leads that connect the trigger signals to each 555?too long a lead length if its picking up electrical noise will also cause false triggering.... ive uploaded a switch debounce circuit for edge triggering yr 555 ........
2 things with yr circuit-there is no power on reset....and the 555 needs to be edge triggered as my previous schematic shows with switch debounce......heres a revised 4017 schematic...also make sure there is adequate decoupling across supply lines and on the 555 timer add a 0.1mf from pin 5 to pin 1..........
2 things with yr circuit-there is no power on reset....and the 555 needs to be edge triggered as my previous schematic shows with switch debounce......heres a revised 4017 schematic...also make sure there is adequate decoupling across supply lines and on the 555 timer add a 0.1mf from pin 5 to pin 1..........
I see three problems with your posted circuit.
1. Pin 4 of the 555 needs to be connected to pin 8
2. You need on resistor about 680Ω between the common LED line and ground.
3. You need a decoupling capacitor between +9V and ground, preferably close to the 555.
regarding switch debounce-if the timed period is quite short the switch bounce will cause the 555 to retrigger and the 4017 will recieve more than the 1 desired clock pulse....switch bounce doesnt need to be a problem and there isnt much xtra circuitry to prevent it...also if he has long leads from his console to each circuit,a good clean switching signal is needed i have used 555s for quite a lot of things and switch bounce can cause strange things to happen with a 555.....
Well I have added a few ideas that I obtained from everyone and I think I have a Frankenstin. I have added the debounce circuit and it toggles fine. When I connect the Circuit with the 555 and the 4017 to the second 4017 circuit, I try to go to Prekit (which is the reset) the led will not come on. If I hit the switch again the prekit LED will come on but then change to Setup.
Schmetic attached. Any Ideas?
The ordinary 555 causes a 400mA supply current spike when its output changes state. Then the CD4017 counters get all confused when their supply voltage suddenly drops when they are clocked.
Use a Cmos 555 (LMC555, TLC555 or ICM7555) which does not have such a high current spike.