Knowing full well that there are definitely not enough hours in the day for flying, I decided to buy the lights and get some "kite overtime " I found I loved night flying. But the lights I had purchased fell way short of my expectations! They were not bright enough, They weighed too much and went flat way too quick! This is my "Lighter, Brighter, Runs Longer Flashing LED Version"
The parts you will need to make one flash unit are:
Have a look at the 3909 you will notice the notch on one end and a dimple over pin 1. This piccy will show you the pin numbering and orientation.
The first thing to do is remove pins 3 and 7 (they can't cause confusion now)
Carefully straighten out pins 4 and 5
Wrap pins 1,2,6 and 8 under the IC
Pins 1 and 8 will be soldered together.
Next we trim and shape the legs on the capacitor before soldering it to pins 1 and 2 of the chip. Note the negative leg has a marked stripe down the side of the can and the leg will be shorter.
The negative leg goes to pin 1, the positive goes to pin 2
Fit the LED to pins 6 and 8. The short LED leg (cathode) goes to pin 8. The long LED leg (anode) goes to pin 6.
If you look into the LED the side with the larger metal mass in the cathode. That pin is laso marked by a flat in the round bottom edge o fthe LED.
Now is a good time to ensure that pins 1 and 8 are soldered together as well.
Now fit the newly created flasher unit to the battery holder.
Bend the legs of the battery holder inward to allow the chip to be solders easilly to the pins of the holder.
Pin 5 solders directly onto the positive terminal (the end with the square poking out). And Pin 4 to the Negative. Note the layout so as to leave room for the spar grip to mount via the hole you drilled
Drill a hole in the clear spot left so the spar clip can be screwed into place.
Now is the time to face the LED in the right direction. You might find you need to shorten the led legs.
I try to have the led sit just above the top rim of the battery holder. It makes for a more solid device. The leg length will only be a mystery on the first device you make.
Now screw on spar grip and fit a battery.
I slip a piece of stiff plastic between the positive battery top and the battery holder terminal to act as a switch. It's far less trouble to leave the battery in place than to remove it for storage between fly's.
All that's left to do now is cover the electronics with some sealant (sikaflex. Silastic or similar goo type bonding compound). Hot glue also works.
The battery will power the flashing LED non stop 24 hrs per day for at least seven days.
I have chained 10 LED's together and run them from this one simple circuit and they flashed brightly for approx a week also.
Some of the more exotic LEDS ie blue or green 4volt 7000-8000 mcd type's won't run from this configuration, as they need more voltage. The only change you need to make is to use a twin battery holder (takes two 3volt button cells resulting in 6 volts to the chip) or you can squeeze 2 x 2025 button cells into some single holders.
I have found the fast flash rate best suited to the dual line stunt kites, the faster kites tended to travel too far between flashes when using slower flash rates.
Don't be tempted to buy the cheap LED's, A cheap 55cent LED is usually around 18-80 mcd LED's rated at 3000 to 9000 mcd can be seen for miles expect to pay $1-$7 each depending on color and mcd (brightness). These lights are not intended to illuminate the kite sail but rather to look pretty and aid in tracking the kite.