LED Photon Torpedo Effect

[ajb]

Can anyone please help me with a Circuit layout (veroboard or PCB design as I cannot follow schematics) to produce the effect of a Photon Torpedo Launch for a star trek model I am trying to build.

Th effect I need is for a slow build on a red Led, followed by a White flash and then both lights going out.

Any help/advice would be greatly appreciated.

Kind regards

Anthony

 

[Hero999]

This isn't my department but I'd suggest a PIC for this.

 

[HarveyH42]

Have you tried searching? There have been atleast two threads on this forum asking the same question, one was more directed toward cloning somebody's product on the web (gave the link).

Can't read a schematic? Don't know how you plan to build this yourself, except maybe pestering use about pick and placing each and ever component, then a long drawn out dialog on why it doesn't work and how to fix it... You do know which end of a soldering iron to pick up right?

Search Google. I guarantee you will find atleast one site, which sells the completed project, no burnt hands...

 

[ajb]

Have you tried searching? There have been atleast two threads on this forum asking the same question, one was more directed toward cloning somebody's product on the web (gave the link).

Can't read a schematic? Don't know how you plan to build this yourself, except maybe pestering use about pick and placing each and ever component, then a long drawn out dialog on why it doesn't work and how to fix it... You do know which end of a soldering iron to pick up right?

Search Google. I guarantee you will find atleast one site, which sells the completed project, no burnt hands...

HarveyH42

Many thanks for taking the time to respond. When I said I am not into Schematics I have been able to produce what I need from them in the past using Eagle Layout Software. The reason for the question about Vero or PCB design is that often there are some good people out there who have already built a project and are willing to share the designs they have come up with.

I certainly would not be "pestering" either you or other members of the forum if I could not get the thing to work

 

[ajb]

This isn't my department but I'd suggest a PIC for this.

Hero999,

Many thanks for the suggestion about the PIC. I have been looking for some programming inspiration on the net and have come acrosss a couple of things that may be adaptable to the sort of thing I want.

Kind regards

 

[Blueteeth]

Hi,

Just wondering if you've solved your problem, because I have a few idea's myself, without involving a microcontroller. I reckon a 555 timer, comparator and a couple of transistors should do it..slow ramp increasing the brightness of an LED, via a transistor, theoutput of which is compared with a reference voltage on a comparator, which then triggers, and dumps a charging caps current through another LED. The 'pulse'' LED will flash really quickly and bright.

Let me know if you want me to draw up a rough schem, might even prototype it myself, not that I'm a trekkie

Blueteeth

Ps. Might even be simpler than that, those 555 timers are pretty versatile, as a saw tooth generator it'll output both a ramp and a 'pulse' so the comparator probably won't be needed.

 

[ajb]

Hi,

Just wondering if you've solved your problem, because I have a few idea's myself, without involving a microcontroller. I reckon a 555 timer, comparator and a couple of transistors should do it..slow ramp increasing the brightness of an LED, via a transistor, theoutput of which is compared with a reference voltage on a comparator, which then triggers, and dumps a charging caps current through another LED. The 'pulse'' LED will flash really quickly and bright.

Let me know if you want me to draw up a rough schem, might even prototype it myself, not that I'm a trekkie

Blueteeth

Ps. Might even be simpler than that, those 555 timers are pretty versatile, as a saw tooth generator it'll output both a ramp and a 'pulse' so the comparator probably won't be needed.

Many thanks for taking the time to contact me about this one. Sadly I have still not sorted out a way of producing this effect. PIC programming looks complicated and expensive so is out.

Any assistance you could offer in drawing up a schematic would be very helpful.

Kind regards

Anthony

 

[Nigel Goodwin]

PIC programming looks complicated and expensive so is out.

It's not terribly complicated, and it's certainly NOT expensive - you can get started for hardly any money at all.

 

[Blueteeth]

With that being true nigel, for a single project, it is not always worth getting a few chips, a programmer (build OR buying), downloading the software, and getting to grips with assembly. I reckon its less hassle than most think, I knocked up a programmer, and had my first 'blink LED' program in a couple of hours...but its taken a while to write more complicated programs, and after a couple of years, *seems* easy. Admittedly if I had this task, I would have used a small 8 pin PIC...but I already have everything I need to complete the project.

Even though PIC's (or any micro really) are cheap, its really 'time' thats the problem, and it does appear daunting. Sometimes a good 'ol fashioned dedicated circuit would do, nowhere near as versatile, but the man said no PIC's.

ajb: I've got a fair bit on at the moment, catching up lost work from being ill, but I have some 555's somewhere, I'll breadboard something when I can. As I said before, it 'might' be feasable with a 555 timer, but practice is always different from theory And while the IC is cheap as chips, buying passives (resistors/caps) in small quantities may also be cheap, but it soon adds up, especially for a single device.

Blueteeth

 

[Nigel Goodwin]

Even though PIC's (or any micro really) are cheap, its really 'time' thats the problem, and it does appear daunting.

As for 'time' the thread is now well over 2 months old, that's more than enough time to have become pretty impressive as a PIC programmer!

 

[Blueteeth]

$89? Oh my...

**broken link removed**

Still, must admit, does look pretty cool, but they added the sounds to make it look cooler :/ Maybe I sould go into the 'niche lil circuits' industry? Haven't forgotten about this thread btw, this year is turning out to be a nightmare so far...when I get round to it mate.

Blueteeth

 

[ajb]

Thanks for still showing an interest. I have tried the PIC option (actually bought a dice project that allows you to re-programme it).

Although I have fathomed out the blink options I cannot work out how to get the LED to build to full brightness and then switch off.

I have been looking at the Voodoo FX item and have been tempted to purchase same, however initial cost plus UK postage really makes it far to expensive for me.

I guess you could argue that if I want this effect bad enough the cost would noy be a consideration.

I will keep trying but any advice is always welcome.

Kind regards

Anthony

 

[Blueteeth]

Hey,


Good to hear you're trying your hand at micro's, they can be very handy indeed!

The usual way to 'fade' an LED, whether that is fade in or out, is to use PWM (pulse width modulation). That involves turning the LED on and off, very quickly, but varying the duty cycle, the ratio of on time and off time. The eye averages the brightness, meaning a 10% on time, 90% off time, the led is faint, but at 90% on time, 10% off time, its bright. The period however, remains the same.

There are various methods to do this with a PIC, many discussed in this forum, and many PIC's have one or sometimes two built in peripheral modules, that handle it all for you, you simply configure it for a frequency, and duty cycle. Using a timer, or a delay routine, you can periodically increase the duty cycle by a certain factor (which will determine how smoothly it fades).

Software methods, that don't involve dedicated hardware use timers/delays to achieve the same effect, not always efficient if the PIC in question is doing many other things, but for a dedicated task the programming can be relatively straightforward. Thats why I, and many others, suggest PIC's for this in the first place With one of the limitations of a microcontroller being the pin count, number of I/O's, you would only need 3, one input (for triggering the 'photon torpedo firing' and two, outputs, one for each led. So an 8-pin pic would be more than adequate, preferablly one ith an internal oscillator, reducing the part count/cost even further. Part numbers that spring to mind are the 12F509, 12F510, 12F629 or the 12F625. Or, if you need other tasks contorlled at the same time, like a master controller, a larger 18-pin one like the 16F628A.

I'm still convinced a 'analogue' circuit could do it, but if you're willing to stick at the PIC programming, it'll allow you to modify the effect whenever you want, make significant modications, and add many other goodies to it (like programmed firing sequences). The limit for that is code space, and I can't see it taking up more than a few lines, so 40 sequences would easily fit on a small 8-pin job.

I'm away for a few days next week, hopefully I'll have some time for testing something, just incase a 555 timer is up to it, plus, I'm surrounded by LED's here (buying them up has become a habit/problem) so I need to justify their existance.

Blueteeth

 

[Excelcier]

Hey there.. I think I have a nice neat PWM solution for you.

What do you think about these videos of what I came up with?

**broken link removed**
**broken link removed**

Here's the code I wrote to do this.

**broken link removed**


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**broken link removed**

 

[Excelcier]

Hey there.. I think I have a nice neat PWM solution for you.

What do you think about these videos of what I came up with?

**broken link removed**
**broken link removed**

Here's the code I wrote to do this ( the zip file includes the videos above ).

**broken link removed**


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**broken link removed**