20230105 The Engines are done!

20230105 The Engines are done!

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THE LEDS, THEY HAVE COME

The Warm White LEDs arrived and as soon as I got back home, I started to solder them onto the PCB. The problem with ordering online is that it takes a average of 8 weeks to arrive. So, it was a great surprise that they came within 5 weeks.!

1.21 GIGAWATTS

I can’t find the Ammeter to get the readout but in theory, the two engines needs a whopping 2.46A of current! If I has a 10,000mAH power bank, the engines would stay lit for about 4 hours or so. And not only that, (I am not going into calculation details here) the current limiting resistors would get worryingly warm.

THE PWM SOLUTION

One way to reduce the power consumption and still give a more or less decent LED lighting is to use PWM (Pulse Width Modulation). This means I would have to write a program and design a third board to achieve this. For the time being, here are the shot of the engines which were driven directly from a 5v power source.

AMT Razor Crest Engine with White 5730 LEDs
This is the lighting from four WHITE SMD LEDs, each running at 100mA, 5 times the maximum current of a normal LED.
AMT Razor Crest Engine with Warm White 5730 LEDs
I de-soldered the WHITE LEDs and replaced them with the WARM WHITE versions.
This is the effect of eight WARM WHITE SMD LEDs and one 5mm WARM WHITE LED.
20230105 The Engines are done!
The circuit board design and it fits perfectly into the AMT model.
There are 33 LEDs in each of the engines.
AMT Razor Crest PCB fully lighted with Warm White LEDs.
I had to lower the brightness of my Huawei Phone to let you see all the LEDs in action.
Testing of the Razor Crest engine lighting
The effect is quite nice and bright but once the model is painted it would be another story.
Depending on the paint used which could either reflect or absorb light, I am going to leave the lighting reasonably brighter than it should be.
Brightness toned down to show the lighting effect for the AMT Razor Crest engine
I lowered the brightness of my Huawei phone to get this shot
Razor Crest LED test under normal lights
This is how it would look under normal lighting
Fragile 0802 LEDs break easily when the tpw engine halves are forced to closed without checking.
Again, the brightness has been lowered to show you all the 33 LEDs in action.
I am using a much narrower and more fragile 0805 LEDs (called the 0802) for the outer rign. Notice LEDs 09, 10 and 15 were not lit. I found out later that this was because I forced clamped the engine halves. The sheer force tore the 0802 LEDs out of their connectors.

CHANGE OF PLANS

Since the ULN2003A or even ULN2803 (Datasheet) has a 125mA output when all pins are used, I decided to use some NPN transistors instead. It might work, it might not. And to get a constant current, I am going to power it from a constant current module. Let’s wait and see…
Posted in A Piscean Works Blog, AMT, Computers, Design, Electronics, JLCPCB, Lighting, Model Kits, Printed Circuit Board, Programming, Razor Crest, Scale Lighting, Scale Models, Sci-Fi, Spaceships, Star Wars, The Mandalorian.

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