Wingtip Navigation Lights
by Tony van Roon

Wing Tip Navigation Lights

Parts & Description

All resistors are 1/4 watt, 5%. Unless otherwise posted.
       R1 = 100K-120K
       R2 = 5M6 (5.6 M)
       R3 = 680 Ohm
       R4 = 1K5
       P1 = 2 Meg, trimmer potentiometer (multi-turn works best)
    J1,J2 = Jumper
    C1,C2 = 0.1 uF, ceramic (100 nanoFarad)
       C3 = 47uF, 16V, electrolytic
       C4 = 0.01 (decoupling) ceramic, *optional*, may not be required
      LED = Red, 'Ultra Bright'.
       Q1 = PN100, 2N2222(A), or any other equivalent NPN transistor
      IC1 = CD4001B, CD4011, CD4093, MC14001,or equivalent CMOS
     BULB = Miniature high brightness light bulb, 5v/15ma or Super-Bright LED's.  
            Substitute with 2volt bulbs (Electro-Sonic #1784) if power source is 
            less than 6 volt.  The larger the current of the bulb (e.i. larger 
            than 5v/15mA)  the less bright it will flash!
A KIT for this project is available: [R/C Wing KIT]
This circuit will support up to 4 bulbs and will really look like the real thing. Pulse brightness is adjustable with P1 and Flashrate is steady at 60 flashes per minute or so. Of course, it is not as bright as a strobe circuit.
LED's may be used instead of bulbs, but make sure P1 is turned CCW BEFORE applying power to the circuit or LED's will burn to a crisp. I did some testing with several types of LED's and different colors. Personally I prefer just the bulbs. If you need a red or green light just use some transparent paint on them. Works! Do NOT connect the lights directly to ground! Which means, don't connect directly to '+' and '-' but only '+' and 'c' of T1.
Battery power can be from 4.8 to 15 volt, but 9 or 12 volt would be prefer. A standard 9V Alkaline battery should work for a long time. Also, in the parts list, I mentioned that the 2mm red led can be substituted by a 1N4148-T 'signal' diode. However, the led gives a visible indication of the proper operation of the circuit. Looking at the diagram, the voltage 4.8 - 16volt mentioned shows the flexibility of the cmos IC, the bulbs work better in the 9 to 12V range. (remember to get different bulbs if voltage is less than 6V).
This device was tested for interference with JR, Futaba, HiTec, Airtronics, and ACE radio equipment. None were found. I suggest, however, to keep the device away from receiver and servos.
I do not recommend using your receiver pack (4.8v) to power both receiver and this circuit. Stick with an alkaline 9V setup. To see the datasheet on the MC14001B, just click on it.

Testing and Setup:
Before hooking up the lights and all the wires and what not, you should pre-test the circuit for proper operation as I know by experience that depending on the led type it (cathode/anode) may have to be reversed. Meaning, if the led does not flash, desolder the led connections and put it the other way (cathode to base of T1). As mentioned before, an "Ultra-Bright" or "High-Brightness" type of LED is works best. My personal preference are the miniature bulbs. Anyways, enjoy!

PCB  Lay-out
Also, you can use a decoupling capacitor (C4) close to the IC. Solder a 10nF ceramic type (0.01) between pins 7 and 14.

Trouble Shooting:
Hope it does not get to this point but it happens and is possible. Most 'does-not-work' circuit problems come from wiring errors, missing a connection, or damaging/destroying a cmos device while handling and/or soldering (too hot too long) it in place.
See if you get a pulse from pin 3. No? Disconnect the battery and desolder the led. Connect the battery again and check for a pulse on pin 3. Yes? You have something connected wrong after pin 3, maybe the led leads need to be reversed. Still No? Disconnect everything from pin 3. If you still don't get a pulse you either made a wiring error or damaged the 4001 cmos ic. Check all your wiring carefully. Before replacing the 4001 cmos ic make sure to remove all static from your hands by touching ground for a couple seconds.
Power up the circuit again with a new IC. Before connecting Q1 back to pin 3 check for a pulse first and then disconnect the battery and solder the base of Q1 back to pin 3.

Below is another way of drawing the diagram, have a look.

Wing Navigation Lights

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Copyright © 1996, Tony van Roon