# 9-0 counter. Running lights that goes faster as the segment ticks at 5 until 0

#### jzz1g

Joined Mar 5, 2016
3
Hello!

I already have done the 9-0 counter using JK F/F, decoder, seven segment display and 555.

At the running lights part, i'm planning to do it using JK or D type F/F.

Currently I have a seperate 555 timer for the 9-0 counter and another seperate 555 timer for the running lights. but my only problem is how will the timer react when the segment ticks at 5 so it will go faster.

#### WBahn

Joined Mar 31, 2012
26,398
Are we supposed to just somehow know what this "running lights part" is?

Why should anything go faster when the "segment ticks at 5"?

We are not mind readers. You need to describe your project/problem in enough detail so that we have a clue what you are talking about.

#### jzz1g

Joined Mar 5, 2016
3
I'm sorry for not giving enough details.

It's a simulation of a person crossing a road.

The person is represent by an LED (which will be represented by running lights)
The 9-0 represents the time that the person has to cross the road.

During the 9-6 part of the counter, the LED should run as fast as how the segment is ticking from 9-6.
Once the counter ticks at 5 until 0, the LED should run faster than how it was running from 9-6 without affecting the speed of the 9-0 countdown segment.

I'm using two seperate 555 timers for this circuit. One for the 9-0 countdown and one for the running lights (the person crossing the road).
I'm currently having a problem on how to make it go faster when the the counter reaches 5.

We are only allowed to use JK F/F, D F/F, common gates, resistors, capacitors, decoder, seven segment and 555 timer.

#### WBahn

Joined Mar 31, 2012
26,398
There are a number of ways. One would be to use the output of the counter to increase the frequency of the second 555 timer.

Are you allowed to use diodes?

Another would be for the running counter to count by a greater increment once the timer counter reaches 5.

#### jzz1g

Joined Mar 5, 2016
3
Hello again.

"One would be to use the output of the counter to increase the frequency of the second 555 timer."

I don't get the part of the "output of the counter"

In the counter I used JK F/F, bcd to seven segment decoder and 555 timer to do it. Which output should I use there?

Also I just asked my professor and we are allowed to use diodes.

As for this "running counter to count by a greater increment once the timer counter reaches 5."
The counter for the running lights right?

#### WBahn

Joined Mar 31, 2012
26,398
The first counter has a four bit output whose values are 9 down to 0, correct? The speed that you want the second timer to run at depends on the output of the first counter, correct?

So can you design a circuit that takes the output of the first counter and produces a HI pulse if the second timer is supposed to run fast and a LO if it is supposed to run slow?