Insight needed

[Veearesix]

Ok its been many years since having to design a circuit. as I dig in more of my memory start to serve me.
What it's for- This is a hot wheels race at my church. This is the same as a pinewood derby but we run hot wheels cars down the track using hot wheels plastic track mounted on a wood frame. We are running 6 tracks. I am building ( last minute literally) a circuit that is using leds with photo transistors to signal when a hot wheels car has passed over its location. Above the finsih line I want to have 2 leds per track. 1 bank for 1st and 1 for runner up. its double elimination so 3-6 is not needed. I have working a circuit to give me the outputs @ each track i just need something simple that would take all 6 as inputs and only display the first recieved on led bank A at its track lovcation (1 of 6) and the second recieved on bank B at its track location while disregarding all other signals. Any help would be appreciated.
Thanks
Doug

 

[spuffock]

A microcontroller! PIC16F84 could handle it easily.
More details will take time and someone else will beat me to it.

 

[Russlk]

Take a look at the Pinewood Derby circuit on my website, it may give you an idea. It only catches the first car, but could be expanded to catch the second.

 

[Veearesix]

the wich came first is perfect. but to print and read the details is hard due to the image. Do you have a better scan?

Thanks
Doug

 

[Russlk]

This one should be better.

 

[Veearesix]

Thank You Very much.

Doug

 

[Veearesix]

Ok trying to build it. looking at the 7474 flip flops. trying to figure what is going where. It shows two inputs from the 4011, 1 output ot the relay, two vcc inputs and 1 output not connected. Kinda lost, I downloaded the data sheet for the chip. Got pin #'s for the connections?

Thanks,
Doug

 

[Russlk]

The power connections for the ICs are not shown, it is assumed that everyone knows what they are, or can look them up. The 7474 and CD4011 VCC connection is pin 14, GND is pin 7. The relay has to operate on 16 mA or less, or the 7474 will not be able to drive it. The not connected output is left open.