Timed Billboard

[ucenginerd]

I am taking an electronics design lab, and our project is to build one of those billboards that flip to one of three sides. I'm using a stepper motor, and I've figured out that part of it, but I need some help with the timer.

So, I need to have a delay, and then deliver a string of 16 pulses to my stepper motor. I was going to accomplish the 16 pulses with a counter hooked up to an 8 bit decoder, to give me 16 consecutive pulses, and then I planned to feed back the carry signal with some logic to the clock or enable or something to get it to stop but....

I need help with the timer. I have no experience with CMOS technology at all, and everything I see is for CMOS 555 timer circuits. Can I achieve this with TTL? Also, one design requirement is to have the delay in between times that the billboard switches be variable. I was thinking a variable resistor in the 555 timer circuit or changing the frequency of my clock input.

Please help if you can!

Thanks
ucenginerd

 

[aryajur]

You may want to check out the CMOS IC 4060. Which can generate timing intervals by dividing a clock. You can switch between multiple intervals but all intervals will increasing or decreasing by a factor of 2. Does this help?