A while back I asked for information about installing a landing light
blinker system in an Archer. Now that the job is done I'll share my
experiences with the Great Planetary Bit-Bucket.
First off, I'm very pleased with the system. I want Jim Weir to know his
generosity was not in vain! Thanks again, Jim.
Jim supplied the 2 field effect transistors with electrically insulated heat
sinks and the two surge current limiting thermistors along with a schematic.
The rest of the stuff came from Radio Shack and another local electronics
store.
The particular question in the Archer was how to hook up the pulsed output
across the landing-light switch. Since the LL rocker is essentially
inaccessible to everyone except the original assembly workers at Piper, I
ran a 16 gauge wire through the firewall to the LL connector in front of the
firewall and replace the two wire connector with a three (actually four)
wire connector to splice in the 12 volt pulsed output.
The other head-scratcher was were to place the thermistor since Jim
suggested it would be better to get it out of the cockpit. It ended up on a
small piece of circuit board screwed to one side of the LL. It essentially
became part of the wire that gets taken on and off when the bulb needs
changing.
The one slight mod I did to Jim's schematic was to add 500 ohm resistors in
series with yellow LED's on each pulsed output so the blink rate is visible
in the cockpit. A side benefit of the LED's is that when the LL switch is
on, the LL LED is also on, even when the pulse system is turned off. If the
pulse system is also on, the LED stays on without blinking.
--
Best Regards,
Mike.

http://flickr.com/photos/mikenoel/