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Apr 02, 2017, 04:35 PM
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DIY afterburner led ring for EDF jets - with arduino & WS2812B


Hi,

I have put some led ring on my FMS Super Scorpion EDF jet, for an afterburner effect. I took a flexible strip made with individually addressable LEDS (WS2812B 5050 RGB, also called NeoPixel). The price is about 14 euros on eBay, for 1 meter with 144 leds. For a 70mm fan, only ~35 leds are needed (the strip can be cut at the desired length).

An Arduino pro mini is controlling the LEDs (using the Adafruit_NeoPixel library). It reads the throttle channel (PWM signal, from the receiver) to vary the intensity and the color or the leds. I tried to make it more ‘realistic’, by including some slight (random) inhomogeneities along the ring, and some ‘flicker’ at high throttle. As for the color, it color goes from red, yellow, to blueish. This can of course be customized at will, by changing a few parameters. The Arduino code is available here:
https://github.com/grmis-fr/NeoPixelAfterBurner

Since each led can draw up to 60mA (under 5volts), the total current can exceed 1 amp, and this may be too much for some BEC. So, I am powering the arduino and the leds using a small adjustable step-down switching regulator (type mini-360). In my case the lipo is 4S. This small buck converter could work with 5S too, but not 6S (it would exceed the max voltage of the mini-360).

Ok, now comes the negative point: the luminosity is a bit too low, and the leds are barely visible if you are flying a sunny day I am going to change the colors a little bit in the code, since the red seems the most visible. I may also look for some more powerful RGB leds.
Last edited by grmis; Apr 02, 2017 at 05:26 PM. Reason: typo
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Apr 06, 2017, 04:13 PM
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MartinT's Avatar
Awesome!

Some observations (from personal real life and RC experience ): Afterburners in the modern jets (F-15,16,18, 35 etc.) do NOT glow red nor blue. Its intensity is mostly orange with some yellow to white. Google images of afterburners to see what I mean. Yes you will find some pictures under certain lighting conditions that show blue, but under >normal daylight< operations it's orange and yellow and it's very, I mean V E R Y bright!

Include a random "flickering" effect to make it >seem< more realistic do this at all throttle settings where you have the burner on. But do not vary the intensity to less than say 50%. (do not let the light fully extinguish!)
Set the point where the burner turns on at about 50 to 70 percent throttle, because you want it on >most< of the time when you are in the air (from medium to high power setting), not only when at full power (lipo drain to high to be constantly at full power) and you dont want it on either when at a low power setting when coming in for a landing...

Cover the inside of the exhaust tube with aluminum tape, (or even better: silever duct tape, as that adheres much better, and has that "realistic" texture) that will reflect the light of the LEDS into the tube and make it much more realistic. (and you could do what the Flitetest guys do: use fiber strands to "carry" the light outside behind the nozzle, see picture of my F-16 below)

Like you say: get the brightest, hurting your eyes LEDs, you can find, if you are flying during (sunny) daylight.
Apr 07, 2017, 08:03 AM
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Thanks Martin for your advice. I will try !
May 31, 2017, 11:40 AM
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I'm also looking to do something like this in my freewing 64mm F-18 using two ~40mm amber rings. I would like to program them to start dully flickering around 70-75% throttle and go up from there. how would I go about doing this? I'm thinking I'll need the two rings, a y connector to bridge them, a speed control for them, and another y connector to plug the motor's speed control and the led's speed control together so they both work off the throttle channel on the receiver, correct?
May 31, 2017, 03:17 PM
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Yes, what you wrote sounds perfectly correct. You would need regular leds (not programmable ones), and a brushed motor speed controller. Note however that the system I am presenting here is quite different, since the leds are programmable ones, and I am using some microcontroller to control them (fully adjustable flicker, color, luminosity, ...).
May 31, 2017, 11:20 PM
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would some regular led's flicker at all or have variable brightness based on throttle input or is it just "off/on"?
Jun 02, 2017, 05:29 AM
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If you connect leds to some brushed motor controller, you can get some variable brightness (it would however better to have a dedicated channel with some appropriate mixing with the throttle channel), but no flicker I think. With the present microcontroller system the flicker, brightness and colors are fully customizable of course.
Jun 02, 2017, 11:21 AM
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thanks for the info. i can deal with no flicker but may decide to do the elaborate route
Jun 22, 2017, 02:45 PM
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Hello grmis. I found your project amazing! I'm nevbe in Arduino but I want to use it as a driver for two afterburners in my MiG-29. Link here
I have dummy afterburners, I use hidden one EDF, so I want to built light inside the tubes.
Could you advice me a little?
Thanks in advance.
Jun 22, 2017, 03:39 PM
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Hi Robertus. Thanks for you message. I looked at your Mig 29, and it looks really nice, you did some great build job.

Concerning the afterburner, I think that my arduino system could work quite well in your plane. The advantage is of course that the visual effects (color changes, etc.) are fully customizable, just by changinga few parameters in the code.

In my setup the leds are pointing toward the interior of the tube (I did not want to introduce any drag), and this limits somehow the visibility on sunny days. However, since your exhaust tubes are not actually pushing the plane, you could place more leds, and perhaps have them pointing toward the rear.

Do not hesitate to ask here if you have any specific question. And please post some pictures !

G.
Jun 23, 2017, 12:22 AM
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Thanks, the main question is how I should connect two sets of LEDs? Using Y cable, or connect to the different pin in Arduino and create separate code for it. Or maybe there is another, better way to do this?
Jun 23, 2017, 03:01 AM
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Quote:
Originally Posted by robertus
Thanks, the main question is how I should connect two sets of LEDs? Using Y cable, or connect to the different pin in Arduino and create separate code for it. Or maybe there is another, better way to do this?
You could simply put two led strips in series for the data line (and in parallel for GND and +5V power lines). There would be nothing to change in the code apart from the total number of leds (adding the length of the two strips). From the point of view of the Arduino, it would just be like a single longer strip. With just a Y cable it would probably not work, because these WS2812B leds are individually adressable, and there is a serial data line connecting each led to the next one.
Jun 23, 2017, 01:55 PM
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I see, thank you for help.
Oct 20, 2017, 09:39 AM
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5546dug's Avatar

After burner


Hi Grmis

Looking at the pics of afterburner I see two capacitors.

I I believe would be the 1000 mf for the Neo pixil, wondering what the second is for and size, & placement with regards to the pro mini.

As there is a adafruit rgbw strip (144) now in stock do you think there would be any value to adding the white to the mix, maybe making the flame seem hotter?

Thanks for the coding , and diy .

Doug
Oct 20, 2017, 09:55 AM
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Hi Doug,

There is one (black) capacitor on the 5v output of the step-down regulator (this 5v output powers the arduino and the led strip). This capacitor is here to filter out some noise coming from the switching regulator (which can be quite important with such small and cheap regulators). It's here for safety (to prevent the arduino from reseting for instance), but the system might work without it, I have not even tried.

Note: The other big blue capacitor that you can see in the plane is actually not part of the after burner system, it is on the 5v output of the ESC-BEC, to limit the risk that the receiver could reboot in case of a brief voltage drop.


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