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Topic: Star Trek Computer Help (Read 20808 times) previous topic - next topic


If you only need on/off control of lots of LEDs, then "charlieplexing" is a useful search term.

Charlieplexing needs quite advanced programming to get the timing right with no flicker, especially when you're trying to do other stuff at the same time. Plus the LEDs are dimmer - not good on a film set with bright lights.

I wouldn't charlieplexing to a noob, the TLC5916 has a much higher probability of success.

No, I don't answer questions sent in private messages (but I do accept thank-you notes...)


I really new to the DIY electronics...
So here is my dilemma...
I'm doing a Star Trek Fan Film and i need a schematic to light up LED's in a pattern...
I have 18 LED's the blink in a random pattern and 5 single LED's that turn on with 5 switches which also have a sound module attached and those 5 lights stay on...

You do know that's not what's happening in the video, though....right?

In the video there are 23 LEDS total, connected in three "groups" of 8, 8, and 7. And it just continually cycles from one group to the next. Which, is considerably simpler than what you're describing since you only need three "switches"/pins.

If you know it's different, and just want to design a 'better' one...that's cool. Just making sure you're not trying to exactly copy the one in the video.

there aren't enough pins for 18 lights how do i hook them up???

Actually, there are. The pins labeled "Digital "Pins 0-13, AND the pins labeled "Analog" can be Digital Pins 14-19. So...that's 20 digital pins.  But, you still wouldn't want to hook them all directly to Arduino. That would be a lot of current. Would need pins to connect to transistors to control the LEDs.

You could also always do something similar to the video, and group some of the LEDs together. Say, instead of 18 individual random LEDs...have 9 groups of two...or, 6 groups of 3...etc, etc... That would clear up some pins for the other lights.

Also, if five lights are either 'always on' or attached to five switches (not sure which way is intended from description)...they really don't even need to be attached to Arduino at all.


That's the way it is supposed to be the 18 are on 1 switch the second switch controls the Red Alert light and the 5 switches control the 5 lights above them...
If someone could help me setup the 18 LED's which i could control in patterns like maybe 4 or 5 lights in a random order that would be great...
Thanks for all the info you people are great...


Aug 31, 2013, 02:14 am Last Edit: Aug 31, 2013, 02:19 am by Osgeld Reason: 1
do you have a breaboard?

if not you sould pick one up, they are fairly cheap and you can just plug stuff into them to make what you want, from there you get some chips, the one I mentioned or better yet the suggested TLC5916

once you have hardware then setting up software would not take too long, it could be up and running in a couple of weeks including waiting for the mail

then there is option B ...yea you could get someone to do it for you, but what about the next prop? you are subject to getting someone else to do it when you could do it yourself

back to design, how are you thinking of doing colors, a bunch of different color LED's, which gets into another topic (cause different colors require different maths), or all the same white LED's and gell's in front of the holes?

something to think about


There will be gels in front of the LED's...
All of them will be white with diffusion...
I need help with setting it up from the bread board to the Arduino...
Like wiring it with resistors and wire positions etc.


gotta work with me man, I dont know what you have already  :D

I got you have an arduino, based on that last post I assume you have a breadboard?

do you have LED's?

what other hardware do you have?

what kind of power supplies do you have available, wall warts, old phone chargers, laptop bricks whatever

wire, soldering irons, hot glue, lucky rabbits foot, 45,000$ laser cutter(you suck if you do)?


whatever you think you have that you think you might need, we can fill in the blanks, and get you setup


Ok I have LED's, Jumper wires long and short, Breadboard, I just bought a Variable Power Supply from eBay, Resistors, 2.1 power jacks, NPN Transistors, Zener Diodes...
What else do I need to help out???
Thank You So Much


Aug 31, 2013, 03:49 am Last Edit: Aug 31, 2013, 03:53 am by Osgeld Reason: 1
how many amps can that power supply provide?

do you have any technical documentation on the LED's?

how many transistors do you have?

do you have spare "raw" wire laying around (heck at the currents we are talking about a old floppy disk or IDE cable is more than enough to scrap for wire)

do you have resistors?

whats your budget, do you want to spend more, or do you want to wire more crap up, keep in mind spending more is within a 10$ range, so whats your time worth to you?

and its no problem, I herd up electrical engineers for a living, I can handle a new guy wanting to get something done, EE's are scatterbrained on good days and they know what they are doing lol


Sounds like Osgeld is really willing to help you a lot. Should try to answer his questions and listen to him.

Other than that, if you want to learn how LEDs work (and don't work), how & why to use resistors, connect in series/parallel, etc (stuff you'd need to know with or without an Arduino)....this is a good resource --
Or, a downloadable PDF version to refer to --

That's the way it is supposed to be the 18 are on 1 switch the second switch controls the Red Alert light and the 5 switches control the 5 lights above them...
If someone could help me setup the 18 LED's which i could control in patterns like maybe 4 or 5 lights in a random order that would be great...
Thanks for all the info you people are great...

So, to rephrase for clarity, you want --

• LARGE BLINKING PATTERN - 18 LEDs "blinking" in random/pseudo-random patterns (possibly in groups of 4-5 LEDs), all connected to one switch...turning the entire group of 18 on/off

• RED ALERT LIGHT - A single LED (or three LEDs blinking in unison?) connected to switch #2...turning that system on/off

• SWITCH LIGHTS - Five more separate switches, each controlling a single LED. Each of which will be either steady-on or steady-off

Coming to a total of --
• 7 Switches
• (18+3+5)= 26 total LEDs
• up to 6 "groups" of flashing/blinking LEDs

This sound correct?


Yes that is correct...
Here is a list of what i have now...
a 4401 NPN Trans
a 3904 NPN Trans
a 470uF 16v Cap
a 22uF 50v Cap
a 22pF 50v Cap
a 103pF 50v Cap
a 16MHz Crystal
a 555 Timer
a L7805 Voltage Regulator
a TIP31C NPN Trans
10k 1/4 watt
150R 1/4 watt
220k 1/4 watt
270k 1/4 watt
270R 1/4 watt
330R 1/4 watt
1 MU 1/4 watt
1.5k 1/4 watt
1.8k 1/4 watt
3.3k 1/4 watt
Tell me anything else i need...
Thank You


I don't know what the specs are on the LED's i bought a couple hundred of them but I could buy some more if need be...


i also have...
ATMEGA  ATTiny 85-20PU
1N4001 50v Diode


Aug 31, 2013, 05:18 am Last Edit: Aug 31, 2013, 05:25 am by Osgeld Reason: 1
ok so it seems like you gotta buy some supplies, you got the stuff to deal with one or two LED's but not a pile of them, so you are going to have to buy some parts to make this possible, as there are limits on what the arduino can provide

my vote is the TLC5916 (*3 = 24 led's under control, so if you wanted to make a 80's style red alert you could) at about 1.65 each + 2-3 bucks postage its the least amount of wiring and external parts to get hooked up wrong

you may have to get some resistors, but still total with shipping less than 10 bucks, and digikey can get it to our part of the country (we are in the same shipping zone)  3 days after the order is filled (keep in mind the 3 day weekend) with the cheap arse option

there is still the question of the power supply, cause at 5 volts your sucking close to an amp (worst case all LED's get stuck on) and the little bitty regulator on board is not going to handle that for long

whats the voltage output of the supply, whats the current rating of the supply, even if you dont have it in hand it should list it on the ebay posting, thats really the last piece of the puzzle to get this working, then we can start showing wiring, and tackle code, which honestly is cake over selecting parts


Here is the Link for the Power Supply...

I can buy more LED's if need be...
I'll order 3 of the TLC5916 now...
anything else I need to get right now???
Thank You

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