night flying setup for dark cloudy days

[quinn]

i finally ordered my night setup. i was wondering if it will help much for those kind of dark cloudy days. also around dusk when the sun just went down. i remember on my plane, the leds werent so helpful until it was actually dark out. winter is here and it would be nice to fly when i get off work at 5 right when the sun goes down.

[sp00fman]

You dont want your heli to be to bright for night flying to prevent blinding. It will help only a little on overcast/dark days. You want more light in that condition.

I did make a set of blades with 2x 1W-led per blade, and made a switch for the frame led-strips to take the full 3s lipo voltage, making them nice and bright. It was absolutely great for dusk/dawn/overcast days. I'm always late from work now and darkness sets in quickly, so i mainly fly in total darknes. Im not sure i will use the overpowered blades often in the future.

[quinn]

Pretty soon it will be all the way dark when I get off work. For now ill just have to see how it does. I got edge main and tails and ordered 4 20 inch strips of LEDs from superbrightleds. I got the brightest ones they had. Not the weatherproof ones. They said about 350 lumens. Not sure if that was per foot or what. Power consumption is 4 watts per foot. I have a 900mah 3s pack that I hope will have enough juice for 2 flights. The whole setup should use 25 watts so 900mah should last about 20 minutes if I did the math right.

[quinn]

Just tested the blades. Pretty much worthless unless its actually dark out. I was hoping they would help a little for days that are really cloudy. Not a big deal though. Ill just have to wait till dark. Might help a little during the day when I cover the canopy and boom with LEDs. I do have some 1 watt LEDs that might be bright enough.

[kavic5150]

Sp00fman what size lipos did you use to power those 1 watt leds?

I did a really bright set for my 6HV. Each led is rated for about 200 - 350ma max current draw. Much too bright to look at up close but very visible on a cloudy day.

I really had to dig through the listings on digikey and mouser to find these. The downside is they are only good for 9 minutes tops with 240mah single cell lipos.

http://www.digikey.com/product-detail/en/AA1010SY28ZC/754-1321-1-ND/1887704

http://www.digikey.com/product-detail/en/LD%20G5AP-4M4N-35-1-Z/475-2851-1-ND/2207264

http://www.digikey.com/product-detail/en/ASMT-QHB2-FEF0E/516-2469-1-ND/2744895

http://www.digikey.com/product-detail/en/LXML-PE01-0080/1416-1032-1-ND/3961137

http://www.mouser.com/ProductDetail/Kingbright/AA3529ZG24ZS/?qs=%2fha2pyFaduj4jhSxJxXtSqbCze3Zz7Z0ULqySlVQ0xE9 gwpVXjyG%252bA%3d%3d

http://www.mouser.com/ProductDetail/Osram-Opto-Semiconductor/LB-G6SP-V2BB-35-1-Z/?qs=%2fha2pyFaduhwDcKvMVOrCj7G7kOjvczSEh4fJAOwyBna PvRdiP0rBVbNa5gsdrM%2f

[sp00fman]

I use 1s240mah packs on all my night blades. Its just what i settled on and is a nice size on a 325mm blade. I can easily fly 10 packs on my night-rig, 6 leds on a blade, before needing a recharge, but it does power off automatic after headspeed drops.
The 1W leds dont run on full power except the red one that tends to be less bright. The 2x 1W led blades have a runtime of about half an hour. These things need an heatsink. There is a topic somewhere in here with pictures.

[cbrkhan]

Originally Posted by kavic5150

I did a really bright set for my 6HV. Each led is rated for about 200 - 350ma max current draw. Much too bright to look at up close but very visible on a cloudy day.

Originally Posted by quinn

Just tested the blades. Pretty much worthless unless its actually dark out.

What is the consensus here? How did it work for some and not work for others?

If your setup worked during cloudy days , then can you please post details? What LEDs and how did you power them? In the end was it worth it or not

[kavic5150]

Originally Posted by cbrkhan

What is the consensus here? How did it work for some and not work for others?

If your setup worked during cloudy days , then can you please post details? What LEDs and how did you power them? In the end was it worth it or not

Your typical night blade led is either an 0805 or 1208 size led and has a current draw of about 20-30ma. Not very good for day blades.

If you select green or white leds and place them on each tip as well as top and bottom they will be visible but not attention grabbing on heavily cloudy days. Regular blue leds (460nm) arent very visible at a distance, look for blue/green, cyan or aqua and a slightly higher (larger number) wavelength.

If its real daytime vis blades you're after, then use 5050 leds and maybe solder 1 or 2 chips as these have 3 chips each. 5050s have 3 leads on each side.

For leds with 100ma or higher current ratings and the same forward voltages as their smaller counterparts you'll need to search somewhere like Digikey or Mouser.

Be sure to check the data sheets before ordering and avoid the ones with odd solder pads.

Yes its worth it, just dont shine leds towards your eyes or look directly at them when you're closer than 10 feet. Remember to close your eyes and check for after images. You shouldnt see them. If you do, and especially if they persist more than 20 or 30 seconds, then you might be damaging your eyes.

[kavic5150]

http://www.digikey.com/product-detail/en/ASMT-QHB2-FEF0E/516-2469-1-ND/2744895

I dont recommend these, they are 10mm square. I dont mind, but you guys will probably not like them.

http://www.digikey.com/product-detail/en/LXML-PE01-0080/1416-1032-1-ND/3961137

These have the difficult solder pads I warned about. Oops.

[Coco66]

Anyway both items are shown as obsolete / discontinued...

[cbrkhan]

Originally Posted by kavic5150

If you select green or white leds and place them on each tip as well as top and bottom they will be visible but not attention grabbing on heavily cloudy days. Regular blue leds (460nm) arent very visible at a distance, look for blue/green, cyan or aqua and a slightly higher (larger number) wavelength.

If its real daytime vis blades you're after, then use 5050 leds and maybe solder 1 or 2 chips as these have 3 chips each. 5050s have 3 leads on each side.

For leds with 100ma or higher current ratings and the same forward voltages as their smaller counterparts you'll need to search somewhere like Digikey or Mouser.

Be sure to check the data sheets before ordering and avoid the ones with odd solder pads.

Thanks kavic5150

For simplicity sake lets just say I am after daylight visibility. In reality, I just want to see my disk in overcast days.Will 5050 work for this?


Questions for you


1.) Found Strips of 3 5050 LEDs. Will 2 on top and 2 on bottom will do?
1.1) How do I check for odd solder pads. I dont know what I am not looking for

http://lighthouseleds.com/yellow-gol...led-strip.html
http://lighthouseleds.com/red-plcc6-...e-backing.html
http://lighthouseleds.com/green-plcc...e-backing.html
http://lighthouseleds.com/warm-soft-...led-strip.html

2.) How does Red and Green sound for daytime visibility. Wavelengths below.

Green Wavelength 515-525nm
Red Wavelength 620-630nm
White Wavelength NONE (What does this mean? good or bad?)
Yellow Wavelength 590-595nm

3.) Full Specs on Red (Questions below)

Size 12v Strip - 5050 / PLCC6 / 1210 - 10mm Width
Color Red
LED Count 5cm (one section 3 LEDs)
Operating Voltage 12v DC
Drive Mode Constant Voltage (12v DC)
Flexibility Flexible
Mount Style 3M Adhesive Backing Tape
Current 60mA / 5cm Section
Viewing Angle 120 Degrees
Luminosity/Brightness 850 - 900 Lumens / Meter
Wavelength 620-630nm
Resistor Built In Yes

3.1) I see sp00fman is using 1s battery even with bigger LEDs. What battery will you use for this setup? 1s, 2s or 3s? If 3s another question below

3.2) Power Consumption Math: If 3 Leds are dreawing 60mA then 4 according to my setup will draw 80mA. So if I had a 80mah 3S battery, it will last me an hour. Is this math correct? Ofcource with 80% lipo max drain I will probabaly need at least 200mah. Will something like below work

http://www.horizonhobby.com/111v-200...--sct-dynb0002


4.) I read in one of the threds that 5050 LEDs are high heat LEDs. Is heat a concern in heli blade application?


Thanks

[kavic5150]

2 top and 2 on the bottom is fine. If you can, try to put one on each tip. Its a bit awkward to do, but worth it. You could angle one slightly down and one slightly up to avoid mounting them on that awkward CF edge. Did I mention that most blades are conductive along that bare edge of CF? Get the good scotch tape and cover it before applying copper tape.

5050 leds have 3 chips per led, so 3 aluminum "legs" on each side. Keep in mind that this raises the current draw, but you'll want at least 2 of them lit for day blades.

Red is not very good for daytime flying. 150mah red leds get a bit lost when flying further away. I dont use yellow leds since they are an ugly (IMHO) amber/orange color.

What size blades are you using? I'd recommend 240mah 1s on each blade for 435mm or longer blades. Single 5050 leds have a forward voltage of 3.2v or less, so no need for more than 1s. That pack looks ok if you want to carefully dissect it.

White leds emit a broader spectrum of light than other colors, so they are easier to see in daylight.

http://www.photonstartechnology.com/...ce_white_light

Heat will not be an issue, even with a blue led and an 8ohm 1/4 watt SMD resistor which is the minimum value I'd recommend for blue.

To match brightness for the white leds I'd recommend 27ohm 1/4 watt or slightly higher, maybe 33ohm or thereabouts. Same for green.

Yellow, orange and red leds will need a much higher value resistor. 91 ohms or so and 1/4 watt.

Since you're using 5050 leds, you can use slightly larger resistors cause the tiny ones are a PITA to solder. Look for 1210 size.

Btw, Spoofman is slightly off his rocker. 1 watt leds should be visible from space on a clear night.

[cbrkhan]

Originally Posted by kavic5150

To match brightness for the white leds I'd recommend 27ohm 1/4 watt or slightly higher, maybe 33ohm or thereabouts. Same for green.

Yellow, orange and red leds will need a much higher value resistor. 91 ohms or so and 1/4 watt.

kavic5150 - Can you help me understand how are you arriving at these Ohm recommendations? I dont know much about electronics, so please bare with me.

Lets use a example

Assumptions

1s Lipo Voltage 3.7-4.2: Lets use 4.0v for this calculation
White Forward Voltage: 3.2v
Red Forward Voltage: 2.0v
Continuous Forward Current = 20mA

Formula

(input voltage - LED Forward voltage) / Continuous Forward Current* number of LEDs = ohms

Lets calculate for 1 1210 LED (1 Diode)

4 - 3.2/ 0.02x1 = 40 Ohms (White)
4 - 2.0/ 0.02x1 = 100 Ohms (Red)

Lets calculate for 1 5050 LED (3 Diodes)

4 - 3.2/ 0.02x3 = 14 Ohms (White)
4 - 2.0/ 0.02x3 = 34 Ohms (Red)

What am I missing? Is there a online calculator that you use?


Thanks

[cbrkhan]

Originally Posted by kavic5150

Since you're using 5050 leds, you can use slightly larger resistors cause the tiny ones are a PITA to solder. Look for 1210 size

These 1210 size resistors... are the the regular round type or surface mount?

In any case, can you please post a link to one that you would use?

[kavic5150]

Definitely want the SMD/SMT (surface mount device/transistor) variety.

http://www.digikey.com/product-searc...=0&pageSize=25

http://www.mouser.com/Passive-Components/Resistors/Film-Resistors/Thick-Film-Resistors-SMD/_/N-7gz42Zscv7?P=1yzbpodZ1z0wpn9Z1z0x6d8&Rl=7gz42Zerdl Z1z0wm9uZ1z0x8ahSGT

Those online resistor calculators seem to leave a bit of margin for error. Also that 4.2v lipo should drop to more like 4.15 or so under load.

I'm just finishing up a set of night blades with 2 white, 2 blue and 1 green led. The blue leds have 8ohm resistors and appear slightly less bright than the green or white ones which have 33ohm resistors. These are all 1208 size, sourced from Lighhouse leds.

[cbrkhan]

Originally Posted by cbrkhan

kavic5150 - Can you help me understand how are you arriving at these Ohm recommendations? I dont know much about electronics, so please bare with me.

Lets use a example

Assumptions

1s Lipo Voltage 3.7-4.2: Lets use 4.0v for this calculation
White Forward Voltage: 3.2v
Red Forward Voltage: 2.0v
Continuous Forward Current = 20mA

Formula

(input voltage - LED Forward voltage) / Continuous Forward Current* number of LEDs = ohms

Lets calculate for 1 1210 LED (1 Diode)

4 - 3.2/ 0.02x1 = 40 Ohms (White)
4 - 2.0/ 0.02x1 = 100 Ohms (Red)

Lets calculate for 1 5050 LED (3 Diodes)

4 - 3.2/ 0.02x3 = 14 Ohms (White)
4 - 2.0/ 0.02x3 = 34 Ohms (Red)

What am I missing?

kavic5150 - Thanks for helping out with SMD resistors. Can you help me with how you would calculate ohms for LEDs in example quoted above

[CoolBear]

Originally Posted by cbrkhan

Can you help me with how you would calculate ohms for LEDs in example quoted above

Your math is fine. Resistors are easier to find in some specific values though (say 10, 22, 33, 47, 68, 82, 100 ohms), I'd rather go a bit higher in resistance than lower. (You can get resistors in other values, but they tend to be more expensive, as they may not be in an E series).

Kavic5150 seem to calculate values a bit based on feeling. I'd stick to calculating by ohms law(as you did), easier to avoid running things above spec(shorter led life).

-
CoolBear


EDIT: Formatting error on my part.

[leisure85]

I've ran night equiptment on overcast days. its looks goods.
I would maybe just throw a set of blades on and have fun with it.

[kavic5150]

Originally Posted by CoolBear

Kavic5150 seem to calculate values a bit based on feeling. I'd stick to calculating by ohms law(as you did), easier to avoid running things above spec(shorter led life).

I've made about a dozen or so sets of night blades so far. So I speak from experience, not feeling.

Leds are rated for up to 50,000 hours. In practice its more like half of that. Even if I'm shortening the lifespan of an led by a factor of 4, I will still have 6,250 hours left. And I'm ok with that.

[cbrkhan]

Originally Posted by kavic5150

Even if I'm shortening the lifespan of an led by a factor of 4

How do you factor for this. Do you just include a safety buffer in you calculations? If yes, how do you calculate?


Last how accurate do you have to be in your inputs? Lipos have a voltages of 4.2 to 3.7 and LED specs are posted as 3.2 to 3.6.

Do you just calculate for average of both ranges? Max / Min of both, Min on one and max on other?

Depending on how you calculate, the results vary significantly