Chaser led's

[marvin.the.robot]

Hi,

I've only recently started playing with logic circuits.

I'd just like to find out if I've missed anything here.

Circuit Diagram
What I'm trying to achieve

I'm trying to make and array of LED's that chase up to the end of the line and then chase back (a bit like knight rider) with controls for the amount of array's to be switched on and the speed that the light moves along the line and a trigger to start the chase.

due to wiring limitations and the fact that I want to be able to add more LED's this method I believe will have the least amount of cable running from the controller to the LED's.

if anyone has any pointers as to improve on this please let me know.

Do I pull down all unused outputs on TTL's or does that rule only apply to inputs?

Q1 and Q3 goto a diode each then go through a resistor, will this cause a higher voltage or damage the transistor at all if both Q1 and Q3 are high? or should I put the resistor behind each diode?

Should I put filtering caps on the TTL's? if so where and what value?

Thanks in advance for your help,

marvin.the.robot

 

[Ubergeek63]

no you should ditch the relays:

**broken link removed**

 

[marvin.the.robot]

got rid of the clear switch relay,

Update

but need the other to switch on and off LED's. I need the circuit to be modular so I can add as many LED's and module's as I like. Also need to provide capability to switch RGB LED's if needed.

is a fan out limit, the limit for how many input's an output can drive or the limit of logic gates in series?

 

[marvin.the.robot]

Updated

ok I have updated the circuit, I removed the clear switch relay, but I think I'll keep the led relay just in case I need to switch RGB led's later on.

also I need to keep it modular so I can add as many LEDs as I like, also to keep the amount of wires going from the controller to the LEDs at a minimum.

so unfortunately the 16 Stage Bi-Directional LED Sequencer is not going to be viable.

another question is the fan out limit the limit of input one output can drive or the limit of gates in series.

Thanks again for your help

marvin.the.robot

 

[marvin.the.robot]

bumpity, bump

 

[Ubergeek63]

what are you powering the LEDs off of?

 

[blueroomelectronics]

I could make a fortune selling preprogrammed PICs that sequence LEDs for those Cylon / Night Rider builders