Flux Capacitor Storage Doors. One Last Run....

[Tomcio]

How many triplets of LEDs are you driving? the circuit shown will cycle through a 10 count. So if LEDs 1, 2, 3 & 4 are used on the "flux board" then there is a long wait as it counts to 10 & resets to 1 again. As I recall, the IC can use one of the outputs to reset after x number of count (such as #5).

You can use any number of LEDs and you don't have to wait for the counter to go to 10. You can wire it so it resets after the last LED and starts over. You can also use more than 10 if you add another counter. The instructions on how to do that are in the text below the schematic. It goes like this:
The circuit may be configured for counts less that 10 by connecting RESET to an output pin one above the desired count. Thus, a five channel sequencer could be made by connecting pin 1 to pin 15. Remember that pin 15 cannot be connected to ground in that case.
In that case you only install five transistors and five LEDs and run a wire straight from pin 1 to pin 15 instead of running it to base of transistor number 6.
This circuit is designed to run on 5V and I recommend using a 7805 voltage regulator. This will allow you to connect it directly to the car's electrical system and you don't have to worry about voltage spikes. Even starting the engine will not cause the LEDs to dim or to slow down the "fluxing".

For good results I recommend using multi-chip LEDs. My favorite kind is super flux LEDs with 4 pins. They are available in 1, 2, 3, 4, 5 and 6 chip flavors with each chip requiring 20mA. If you use anything more than 3 chip you will need to use larger transistors. If you want your flux capacitor to be blindingly bright use BD135 for the transistor and go with 6 chip super flux LEDs. Calculate the current limiting resistor for 6x20mA = 120mA. The 120R resistor is calculated to provide about 20mA of current to the LEDs. You can also install a potentiometer here along with a fixed resistor and that will let you change the brightness of the LEDs. Keep in mind that the resistor cannot be less than the maximum current of the LED. A pot will then allow dimming of the LEDs. Cool, isn't it
Parallel connection of separate LEDs is not recommended. Series connection will not work as white LEDs need about 3.1V and this circuit without changes will provide up to 5V. The best choice is to run multi-chip LEDs.

Let me fix the resolution so the picture is actually readable.

4017-2.jpg

[nkemp]

Now that I can read the text I see that it discusses the reset pin and counting to less than ten. Thanks for clarifying.

[SS Spoiler]

Wonder what the average IQ is of DeLorean owners?

[nkemp]

wwhhaaaat?

Tomcio's circuit lights each LED in order starting at 1 and proceeding to 10 (1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4 ,5,6,7,8,9,10, and so on).

Most FC's have 3 LEDs (some have 4 with a center LED) and as such you do not want the circuit to count to 10 but only count to 3 (or 4). If you want it to only turn on/off LEDs 1, 2 & 3 you tie the pin for LED 4 to reset and then it cycles 1,2,3,1,2,3,1,2,3 and so on.

If you did not tie pin 4 to reset and only connected to LEDs 1, 2 and 3 then it would cycle 1, 2, 3, , , , , , , , 1, 2, 3, , , , , , , ,1, 2, 3, , , , , , , , where no LEDs were lit in the blanks and that is not how the FC operates (it screws with the flux time constants and may result in inaccurate temporal displacement.

[Timebender]

As cool as these are, and Flux Capacitors in general, I'm kind of surprised no one has built their own that would seem more realistic using today's LED technology, with maybe a string of flat low profile LED's that would simulate plasma or energy pulsing through the tubes vs. the on off on off tech of the 80's. I know the desire to be movie accurate (My R2-D2 is and approved by Lucas/Disney for official events, etc.), but how cool would it look if it seemed like real energy was flowing down each tube?

[Hank]

Here's the pre-made kit that Sal used: http://store.qkits.com/moreinfo.cfm/FK115

It's also a 555 and 4017 counter.

He wired it up so three LEDs in each "band" light together, and I think he has four bands.

And I've discovered that this circuit works down to 3.5 volts, and up to 13.8 volts, but the LEDs to get quite dim at 3.5 volts.

[David R]

Hank, thanks for posting that kit! What a cheap and easy way to get a flux lighting circuit. Does using only 3 bands of LEDs work on the same principle as Tomico's circuit, connecting the would-be 4th LED's lead to a reset pin?

[Hank]

Hank, thanks for posting that kit! What a cheap and easy way to get a flux lighting circuit. Does using only 3 bands of LEDs work on the same principle as Tomico's circuit, connecting the would-be 4th LED's lead to a reset pin?

Before I put my FC back together, I did take some photos of the circuit board and how the LEDs are wired.. I'll try to find them and post them later today.

I know Sal said he did make some mods to the circuit board, but was not specific.

[Hank]

I also have a second LED kit I posted above, just without the ICs (I harvested them from the kit to replace mine). If someone wants it (i.e. bring your own 555 and 4017 ICs), you can paypal me $10 (including US shipping). The kit actually might have a good 4017, since only the 555 timer was blown on my board, but I'd have to look and let you know.

[Mark D]

As cool as these are, and Flux Capacitors in general, I'm kind of surprised no one has built their own that would seem more realistic using today's LED technology, with maybe a string of flat low profile LED's that would simulate plasma or energy pulsing through the tubes vs. the on off on off tech of the 80's. I know the desire to be movie accurate (My R2-D2 is and approved by Lucas/Disney for official events, etc.), but how cool would it look if it seemed like real energy was flowing down each tube?

The real flux capacitors built for the screen used cars look pretty realistic (if you can call it that) compared to a lot of the knock offs like the diamond select and some of the other high dollar replicas. The sides of the plexi diffusers are not supposed to be visible like on the DS replicas...the intention of the diffuser on the real flux was to make it look like the glass relay tube itself was lighting up. There was no way to drill into a glass tube and install lights without shattering it so they built a frosted light bar below it to give the illusion it was lighting up.

There are few different other variables that go into making the effect look real...the number of lights and spacing between is critical, as is the flashing rate to make the motion of the lights appear seamless. When done up like the screen used flux capacitor a replica can look just as good.