Hi, I'm looking at adding on an LED Circuit controlled from digital Pin of an Arduino Mega 2560. I want to mount an LED or clusters of LEDs, lamps etc on the ends of the 8 arms of an Octa 8 Multi-rotor to provide a wide angle of visibility. Can anyone recommend the best LEDs, clusters or bulbs that might solve this. The LEDs need to still be clearly visible at 150m to provide good orientation of the Multirotor. Multi-rotor system is powered from 4 packs of 6S Li-Po's routed to a distribution hub, 22.2v (3.7v nominal voltage per cell). What would be the most best way to do this. Looking for good solution and willing to pay extra for the best components etc for the solution, but needs to be reasonably lightweight and not consume to much power. Must ensure the system can't cause damage to the conneted Arduino Mega 2560 so some sort of isolation been the cicuit may be safer? thanks Paul
Are these for illumination (light up the ground/obstacles) or for indication (can see the aircraft from afar)?
If indication, do you want to be able to see it during the day, or during the night, or both?
Hi, for daylight hour operation. For illumination and battery low voltage warning. Normal system battery the leds are constantly on and on low battery voltage fast flashing. This functionality is already written. But I now need a decent illumination system. Some sort of driver to provide the current etc. Have considered led bulbs half dome shapes and tubes etc which might show well and give good angle of illumination but not sure how to how suitable these are really as a solution and how best to integrate them with the system. Getting a special board as a single additional system board or multiple boards for each led made up is an option I would definitely go with if that was the best solution rather than an off the shelf type solution. The Leds could be anything from a single LED to a dome on a board up to 45mm diameter dome, square or cuboid etc, fitted under each arm. Critical that this circuit must not effect the micro controller, increase likely hood of brown out or malfunction etc. thanks
Well to see an LED in the daytime you're going to want to run it at a pretty high level like 350mA. If you want one on each of 8 legs that's almost three amps, that's a lot of power. You're going to run the battery dry pretty quickly. You might reconsider and just use one high-power LED instead of eight.
Google "BuckPuck" LED drivers. There's a few different flavors to choose from, should be able to find one that suits your needs.
I'm using 4 5500mAH Li-Po's, my motors a drawing about 6A each to hover (48A total). I think the 3A should acceptable, The visibility factor is very very important, need it for orientation as well as indication of low battery. For the Orientation was going to split the LED coloring; rear two arms red then right 3 arms green and left 3 arms blue to help prevent disorientation at distance. I'm getting in excess of 20 minutes flight duration, so I think 3A equates to about 1 minute of flight time.
So is it better to have the BuckPuck driver close to the supply voltage with long wires along each arm or the Buck Puck nearest the LED end of the arm.
http://www.luxdrive.com/content/3021-BuckPuck.pdf Figure 16 shows the connection to the micro controller I have to use? It says for long lengths.
Its says for extend wires of 18inch to the led you need a capacitor, I take is an electrolytic on the input to the BuckPuck. I reckon 470UF with a suitable voltage rating should work for this but how do you calculate what need for this.
It says it needs a REF from the micro controller can this suck power from the micro controller if I attach to many of these BuckPucks to power lots of LEDs. Worried this could result in brown outs. Why does it need the BuckPuck need the REF from the microcontroller? Is it best to use say a 700mAH BuckPuck to power 2 LEDs in parallel for two arms or just use separate 350mA BuckPucks on each arm for 1 LED each arm.
What LEDs would be best to use?
The BuckPuck does not use REF from the microcontroller. Teh BuckPuck provides up to 20mA of +5VDC to run a microcontroller, but it''s optional, you should just leave it disconnected in your case. The only thing you'll connect from the microcontroller is the Ctrl pin so you can turn the LED on or off in your sketch.
You don't want to wire LEDs in parallel. However if you have sufficient voltage it's very efficient to run them in series. Since you have 22V available I would run two 350mA BuckPucks, each with four LEDs in series.
When running LEDs in series, you do not need to increase the driver mA. So with four LEDs in series on a 350mA BuckPuck, all four LEDs will each output their full 350mA.
I'm partial to Cree LEDs, personally. XR-E are acceptable but XP-E or XP-G would be my preference.