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Author Topic: AMT 1/650 TOS Romulan BOP  (Read 32425 times)

Offline Shawn McClure

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Re: AMT 1/650 TOS Romulan BOP
« Reply #30 on: June 07, 2016, 09:45:44 am »
Is this a type of
To build or not to build.... that is the question.   The answer.... build... Duh.

Offline Shawn McClure

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Re: AMT 1/650 TOS Romulan BOP
« Reply #31 on: June 07, 2016, 09:47:24 am »
Well, that quote thing didn't turn out... 

What I said was that the led's last tons of hours but usually fail so you let them "burn in" for 24 hours.

Looks great Steve.
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Offline MSgtUSAFRet

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Re: AMT 1/650 TOS Romulan BOP
« Reply #32 on: June 07, 2016, 10:06:21 am »
LOL! I have the same problem with the text boxes, Shawn!

Thanks for the reply!

Steve
"To be honest with you, Picard, a significant number of my crew members have expressed a desire to return even knowing the odds. Some because they can't bear to live without their loved ones, some because they don't like the idea of slipping out in the middle of a fight."

Offline Caladonis

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Re: AMT 1/650 TOS Romulan BOP
« Reply #33 on: June 07, 2016, 12:33:58 pm »
http://www.ohmslawcalculator.com/ohms-law-calculator
and
http://led.linear1.org/led.wiz

How I hand calculated the values for your first example
with one red and one green LED

Red led voltage @ 20 MA should be 2.0 v
Green led voltage @ 20 MA should be 2.2 v (assuming it is not the 3.3 volt version)

So 2.0 volts + 2.2 volts = 4.2 volts across the leds
Then 9 volts (source) - 4.2 volts (for both LEDS) = 4.8 volts that must be dropped by the resistor @ 20 MA

So 4.8 volts divided by .02 amps (20 MA) = 240 Ohms


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« Last Edit: June 07, 2016, 04:54:38 pm by Caladonis »

Offline simi

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Re: AMT 1/650 TOS Romulan BOP
« Reply #34 on: June 07, 2016, 01:19:16 pm »
I think Shawn was saying that when properly resistored (not sure that's a word) - LEDs last in the 10's to 100's of thousands of hours.  IF you have LEDs that do not have enough resistance - it can/will greatly shorten their lifespan.  This is the purpose of the burn in period.  Usually if an LED fails due to not enough resistance - it will happen in minutes or a couple of hours.  So if things go well overnight - you have a good confidence level that it's good for the life of the model itself.

I agree with the assessment that the 240ohms is a bit low for my tastes.   In my 9v systems, I usually do a 470ohm resistor.  This "slighty" tones down the brightness and is well above the amount required to let the LED live a normal life-span.  In general, make sure you are at or above the resistance level indicated by whatever calculator you use.

Hope this helps!

Cheers!

Simi
As a software architect, I'm pretty darn good.  As someone with knowledge of building things in the real world, well, I'm a software architect.

Offline Shawn McClure

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Re: AMT 1/650 TOS Romulan BOP
« Reply #35 on: June 07, 2016, 02:15:45 pm »
That was it Simi.
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Offline MSgtUSAFRet

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Re: AMT 1/650 TOS Romulan BOP
« Reply #36 on: June 07, 2016, 07:26:32 pm »
Whoa! Thanks for the incredible responses and clarifications!

And Thanks for your patience with my lack of knowledge, but I have a few more questions.

Don used a specific forward voltage for specific colors - i.e. Red led voltage @ 20 MA should be 2.0 v; Green led voltage @ 20 MA should be 2.2 v

Is there a standard forward voltage chart/guide/standard/thingie that lists the most common LEDs with their colors? Now, I have seen a plethora (always wanted to use that word!) of charts on the internet of various opinions and websites (almost as common as belly buttons!) which is why I ask.

Another reason I ask is the package I picked up from Radio Shack implied all the 5mm and 3mm LED contained therein had a forward voltage of 2.4. Now, using that FV for my formulas

(9V-(2.4*2))/0.020 = 210 Ohm and since you can't go lower, I went to the next standard higher 220 Ohm. This was also the solution http://led.linear1.org/led.wiz gave me - so I felt comfortable with the solution. The same held true of the other series - hence my confusion.

Again, I am learning about this whole aspect so thanks for your help. But, is there a standard Forward Voltage, as opposed to a range, that I can use to be more precise?

Thanks! I appreciate the wonderful insight and wisdom here on the forum!

Steve

« Last Edit: June 07, 2016, 07:33:13 pm by MSgtUSAFRet »
"To be honest with you, Picard, a significant number of my crew members have expressed a desire to return even knowing the odds. Some because they can't bear to live without their loved ones, some because they don't like the idea of slipping out in the middle of a fight."

Offline scottminium

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Re: AMT 1/650 TOS Romulan BOP
« Reply #37 on: June 07, 2016, 08:30:23 pm »
MSgt,
I sent you a long reply, but the bottom line is you can go with substantially higher resistance that will only marginally affect brightness yet substantially prolong LED life.  Short version: test your lighting plans on a 'plug in' breadboard and if it works at higher resistance, go for it!  You can typically cut the 'rated' current in half and still have bright lights.
"I rather believe that time is a companion who goes with us on the journey, and reminds us to cherish every moment... because they'll never come again."

Offline Caladonis

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Re: AMT 1/650 TOS Romulan BOP
« Reply #38 on: June 08, 2016, 05:19:46 pm »
Your calculations are perfect! As you surmised, the problem is the forward voltage level for the leds. Also, the comment by scottminium is spot on too as the larger the value of resistor you are able to get by with (less brightness) the better as it will cause a decrease in the current through the leds. This will both extend their life and if you're using a lot of LEDs the model will run cooler using less power overall. Also helps if you want to use external power and should accidentally plug in a 12V supply. i think Boyd designs around 12V for leds and led strips, and runs them at 9V.


This is from the http://led.linear1.org/led.wiz site and is about as good as it gets for standard leds

Diode forward voltage

If you have good specs from your supplier, you'll want to enter the typical forward voltage here. Ideally you'll have something that looks like "3.4V @ 20 mA" which defines forward voltage and current at one point on the operating curve. If you don't have good specs, here's a table to help you make decent guesses:
color   voltage (Volts)
IR   1.5
red   2.0
orange   2.0
yellow   2.1
green   2.2
true green   3.3
blue   3.3
white   3.3
UV   3.3
blue (430 nm)   4.6

Offline cmfowler

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Re: AMT 1/650 TOS Romulan BOP
« Reply #39 on: June 08, 2016, 06:20:07 pm »
Steve, I agree with what everyone else is saying.  I plan to run my Enterprise at 9v most of the time but everything is setup for 12v.

Great work so far, looking forward tonseeing more.

Offline MSgtUSAFRet

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Re: AMT 1/650 TOS Romulan BOP
« Reply #40 on: June 09, 2016, 08:05:46 am »
Gentlemen,

I am truly overwhelmed by the assistance you all have offered and the solutions you have given! I feel like I am drinking water from a firehose in learning about all of this! WOW! And THANKS!!

Shawn and Simi - thanks for the explanation of the purpose of the "burn-in". I followed your advice and left the breadboard on overnight and, when I checked on it the next morning, ALL of the white LEDs didn't work and the colored LEDs were dimmed from the night before; so, I will re-calc based upon recommendation mentioned here.
Don and Scott - thanks guys for explaining these concepts; to quote "Galaxy Quest", "Explain as you would [to] a child." I am learning though! ;D Thanks, Don, for the easy reference chart!

Chris, thanks for stopping by! I can't wait to see more either! ;D

Okay, while I re-do the lighting scheme, I have more to show:

I prepped the Aft cutout with finish-lines using a bur and a dremel. As far as finishing is concerned, this may have been a pointless exercise and, now that I think about it, I am going to re-contour the cutout with "something" (sheet styrene or nail acrylic - hadn't decided which yet) so I may not need the finish lines. BUT, and there is always a big BUT, the additional exposed surface will enhance the bond between the nail acrylic and the cutout - whenever I go to re-attach it!

20160607_204144

I also marked and removed the dorsal of the Superstructure. This will allow me to add a bit of 0.080" sheet styrene to the superstructure to create a more streamlined feel for the model. I "pilfered" this rare photo from Gerald Gurian's website http://www.startrekpropauthority.com because it shows the actual shape and height of the TOS Romulan BOP Superstructure on the production model - which is not as flat and short as is the Diamond Select display model I have.



I should really spend some time fulfilling my promise to quit cutting things and attach and fix all the things I have cut off to move forward; except that dang "Honey-do" list that keeps rearing it's head!

Till then and, as always, I would love to hear your thoughts and input!

Thanks again, guys, for the Electronics help!

Venerate the Immortal Emperor!

Steve
« Last Edit: February 27, 2018, 03:17:55 pm by MSgtUSAFRet »
"To be honest with you, Picard, a significant number of my crew members have expressed a desire to return even knowing the odds. Some because they can't bear to live without their loved ones, some because they don't like the idea of slipping out in the middle of a fight."

Offline Shawn McClure

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Re: AMT 1/650 TOS Romulan BOP
« Reply #41 on: June 09, 2016, 10:41:06 am »
Looks pretty in pink Steve.

I'm glad you did a burn in, that would have saved you tons of headaches.

Speaking of LED's.  I just always get the packs from HDA model worx  http://hdamodelworx.com/

They come with proper resistors packaged with the LED's so it takes the worry out of having the wrong resistors. They have other killer products in there too.

Something to think about.

Shawn
To build or not to build.... that is the question.   The answer.... build... Duh.

Offline Caladonis

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Re: AMT 1/650 TOS Romulan BOP
« Reply #42 on: June 09, 2016, 03:26:52 pm »
Coming along nicely, I love what you have done so far. That kit out of box is just so wrong. GOOD JOB!

Offline MSgtUSAFRet

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Re: AMT 1/650 TOS Romulan BOP
« Reply #43 on: June 13, 2016, 08:32:51 am »
Looks pretty in pink Steve.

LOL, Shawn! Yeah, I was kinda going for the ST:TAS color scheme!



It was actually the light from my breadboard LEDs.

Thanks, Don (Caladonis)! It is wrong coming out of the box. But when you are 10 y.o. and building this model, you don't care much for accuracy.
Plus, before the days of internet, it was difficult to find a picture of anything Star Trek; much less Romulan! Still, thanks for the kind words!

A HUGE "Thank you!!" to all who offered advice and informed me about lighting! I am sure I am not done asking questions (so much to learn!) but I think I have a handle on the resistance for now.
Here is what I have. It is rated for 9V+. I took the 9V Ohms Law calculation and whatever the answer was, I added 100 Ohms and came within plus or minus 10 Ohms of the 12V resistance.
I left a 9V battery on the breadboard for 5 hours for a burn-in. When I came back, I found only the red LEDs were lit. My first thought was "Not again?!" but when I plugged in a fresh 9V,
the lights lit; well and bright! Looks like I had drained the battery; which sold me on the 9V plug in power supply.

20160610_071936

In my last update post, I had removed the Dorsal section of the Superstructure to, hopefully, create a lower, more streamlined profile for the Dorsal Hull. I flipped the model over and,
on a sheet of 0.080" styrene, I traced a pattern and cut it out. I fitted it to the cut out and, leaving a bit of it higher for finishing purposes, attached it to the Superstructure.

20160610_080045

I also attached the Aft section cut out (finally) with some nail acrylic. Here is a shot after I have done some finishing on the model.

20160613_053046

I have to admit, I am struggling with achieving the contours of the Aft section. The Nail Acrylic, while excellent for filling seams and creating replacement parts, sets to a greater hardness
than the styrene. So when I go to finish down the acrylic with a bur and Dremel, I end up gouging the styrene with very little damage to the acrylic. *Sigh*

I guess I will have to resort to using elbow grease on the dissimilar materials! AH! The life of a modeler!

Hee hee! Still, I am have much fun and am learning A LOT about materials, lighting, photography (no more pink ships!) and modeling! In the end, it is still the thrill of creating something from
nothing, the power of creation, that keeps me coming back to the bench!

Till the next update, thanks for reading and double thanks for the comments and input!

"Gentlemen... may the wind be at our backs. Stations please!"

Steve
« Last Edit: February 27, 2018, 03:28:38 pm by MSgtUSAFRet »
"To be honest with you, Picard, a significant number of my crew members have expressed a desire to return even knowing the odds. Some because they can't bear to live without their loved ones, some because they don't like the idea of slipping out in the middle of a fight."

Offline MSgtUSAFRet

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Re: AMT 1/650 TOS Romulan BOP
« Reply #44 on: June 20, 2016, 08:00:02 am »
Good day, Everybody!

I hope you had a great and productive weekend.

I attended Comicpalooza in Houston this weekend. I was able to see Lou Ferrigno, Carl Weathers, Michael Beine and, most notably, Walter Koenig! While it was much bigger than last year’s show, I was disheartened by the lack of Star Trek paraphernalia for sale and display. Despite this being the 50th Anniversary of the show and a new Star Trek movie out in July, I thought there would be an overabundance of stuff to be had, but I guess Deadpool grabbed most of the attention.


I also managed to find the International Plastic Modelers Society (IPMS) of Houston booth and had a nice chat with the people manning the booth. One of the gentlemen there was building the Space Battleship Yamato from Star Blazers. Nice!

Still it was worth it to be around fellow nerds! ;D

I’ve made some progress on my build and thought it was time for an update. :)

I decided to focus on something other than the Stern of the ship for a while. When Boyd did his build of the BoP, he started out with drilling the holes for the lights, so I figured that would be a good thing to do, too!

I have the Diamond Select display toy and decide to use it to make a pattern for the windows. Besides, the AMT recommended window size is a bit too big for my tastes and I liked the arrangement of them on the toy.  So I taped the rubbed pattern on the model and made a small indentation on the model through the pattern.



 I drilled a few windows to see if I liked the placement and then thought I should see where my grid lines are relative to the superstructure; only to find out my window placement was off. SOOOOOoooo, I stopped drilling and started marking the gridlines. This was the final placement. Now I just have to scribe them in.



And here is the final…



This one shows the window/sensors after drilling and clean up.



So far, I’m happy with the windows but the gridlines are not as uniform in width as I would like. Plus, scribing on a curve is a bit difficult. Trying to think through exactly how I should have done that so I can do better with the ventral hull.

Welp, that’s all for now. Still working through the process to light my “uncomplicated” build! Next step, I think is to prep the wings with wires and then work on getting gridlines scribed in them as well.

Slowly but surely builds the model! Good thing I am not judged by speed, otherwise I wouldn’t even qualify! ;D

“We are creatures of “duty”, Captain. I have lived my life by it. Just one last “duty” to perform.”

Take care out there!

Steve
« Last Edit: June 20, 2016, 08:02:04 am by MSgtUSAFRet »
"To be honest with you, Picard, a significant number of my crew members have expressed a desire to return even knowing the odds. Some because they can't bear to live without their loved ones, some because they don't like the idea of slipping out in the middle of a fight."

 




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