This simple circuit caan be found all over the internet, thought it would be a good idea to make a PCB for it
I wanted to make it so you can experiment a little, so the 555 timer has some flexibility
the counter IC is CD4017
Pin 1 is negative, pin 3 is positive
The top of the timing chain is on a separate pin (pin 2), you can either link it to supply, turn it on or off,
or add a capacitor to the pin, then pulse the pin with a button to make a sort of random number generator,
the led's start at high speed, but slow down to a stop as the capacitor discharges
You will notice i have designed a trim pot and resistor in parallel for 2 positions in the chain, R1, R2, R5, R6.
you can use either in these positions for fixed or variable values
Or you can add a pin header into 2 of the trimpot terminals for an external pot
R3 and R4 are 1K pull down resistors for inhibit and reset



Download Gerber file here




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