Need your help with aproject

[CAPtain232]

Hey guys

New to the forum obviously. I am an electrician, but not very good with electronics.....mostly high voltage industrial applications.

I also build giant (9 and 10 ft wingspan) scale radio control airplanes. I am wanting to do a KNIGHT RIDER theme with one of my planes. I would like to build a light bar that chases in both directions. I know that I can buy kits that will chase, but I think they are just in one direction and the biggest ones I have seen so far are only 10 LEDs...... I would like to build this light bar 3 to 4 inches long with LEDs close together to get that "moving" feeling.

I would like to learn what all of the chips, transistors etc etc do in a circuit like this..... If someone can design it and email me the schematic (with critical part numbers) so I can build it, it would be greatly appreciated..... I fully intend to come back here onc I have the parts to start asking questions and learn from this project.

Thanks
Jeff

 

[panic mode]

two directions is not a problem. how many LEDs would you like? less than 16? less than 32?
are you comfortable with CMOS (and precautions on static)
or you prefer TTL? would you be intersted to do project with
microcontroller?

 

[stevez]

Jeff - maybe you'll get lucky and someone who has done "chasing" lights will have a ready solution. If not then there is still likely plenty of help to be found. So many contributors to this forum have the skills - the problem is describing what you want and getting answers that mesh well with your skill and resource level.

On the off chance that you won't get lucky, it might help for you to define a couple of things (that come to my mind anyway):

1. Is only one LED on at a time (on each side) and is the transition from off to on abrupt or gradual. I am visualizing this an see where several LEDs might be powered to look like a moving bar rather than a spot.

2. Is each side exactly the same - meaning can you drive an LED and it's opposite twin at the same time?

3. How many LEDs will you have? Have a bare minimum in mind and some sense of the maximum.

Good luck - you'll get the job done.

 

[CAPtain232]

Thanks for the replies guys.....

CMOS is probably NOT a good idea due to the fact that the unit will be in close proximity of an ignition system for the gasoline engine.

Microcontroller may not be a bad idea, but again WEIGHT is very important.....

TTL is probably going to yield the best results for overall application; weight and functionality


STEVE.....some good questions.

If memory serves me correctly, on the KNIGHT RIDER, the light bar was only lit on one side at a time, chased to the right and then to the left.

I believe the best way to make the light look as though it is moving is to have at least two lights on at a time.... at the very start, one LED (say on the right) by itself and then second step would be the first LED and second LED. 3rd step would be first LED goes out, second LED still on and third LED on. 4th step second LED out, third LED on and fourth LED....etc etc

If it makes it looks better, I am open to having 3 LEDs on at a time...I don't think it will be necessary though.

HOW MANY LEDs TOTAL....???
I am not sure. Ideally I want a light bar that is between 3 and 4 inches long and cram as many in as possible.... I think if I had to, I can have a small space between each LED......
I will measure an LED (width) tonight to see just how many can fit in a 3 to 4 inch space if they are tight against each other....

Thanks guys and keep the questions/ideas coming

 

[audioguru]

Bill Bowden has lots of Knight Rider circuits. This one works with a battery voltage from about 4.0V to about 6.5V:
**broken link removed**

If you use TTL then the battery current will be much higher than with Cmos. TTL would need a higher battery voltage then a voltage regulator.
Static doesn't bother Cmos parts that are connected in a circuit with unused input pins connected properly.
Note that some Cmos circuits are ordinary Cmos with a supply voltage rating from 3V to 18V, while others use 74HCxx high-speed Cmos with a supply voltage rating from 2V to 7V max.

Five Ni-Cad or Ni-MH cells produce 6V over most of their discharge but are 7.5V directly from the charger.

 

[CAPtain232]

AUDIOGURU

That is great.... I have figured that I would like to have 4 LEDs per inch of the light bar. So if I build a 4 inch long light bar, 16LEDS wil be utilized

I will be trying to get in touch with Mr. Bowden

Thank you

 

[panic mode]

Static doesn't bother Cmos parts that are connected in a circuit with unused input pins connected properly.

that's true, but most cmos problems happen with newbees before the cmos is in the circuit or circuit is completed. :lol: