Today's Message Index:
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1. 10:39 AM - Eye Beam Mini LED / RF interference (jonlaury)
2. 01:15 PM - Re: Eye Beam Mini LED / RF interference (Robert L. Nuckolls, III)
Message 1
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| Subject: | Eye Beam Mini LED / RF interference |
Listers.
I posted this about a year ago, but now I'm down to the short list of squawks so
this has moved to the front burner.
I have installed an EyeBeam mini LED cabin light in my composite airframe. Unfortunately
I do not have a schematic of the unit, but it uses capacitance (touch)
to control the on/off function and dimming.
The LED is powered by shielded, twisted pair power and ground wire cable. In the
same small enclosure on the ceiling there is a 4 ohm 1.25" x 1.75" cabin speaker
and it's power and ground comes from 180 deg away from the wires feeding
the LED with no parallelism or overlap. The shield for the LED is grounded at
the ship's single point ground bus.
The problem:
When I key the microphone, the EB turns on. If I key it again, the EB begins flashing
uncontrollably. It is unresponsive to the dimming control and the on/off
switch. The only way to stop the flashing is to disconnect the EB from power.
The EB works as intended when connected to battery power independent of the
ship's electrical system. The LED also turns on if I power up the audio panel
with the speaker selected. Yesterday it turned on when my hand got near it.
Attempts at a solution:
Thinking that the the magnetic field of the speaker magnet may be causing the problem,
the speaker was disconnected and the mic was keyed. The EB exhibited the
same uncontrollable flashing upon keying the microphone. I installed elongated
ferrite donuts on the LED cable at various locations and on the speaker wires
to no effect.
I contacted the manufacturer and their solution was some huge boss hog thing that
I'm sure would prevent ET from phoning home.
If co-located with the LED, it needs to be small enough to fit in about a 1/2"
high x 1.25"OD cylinder
Any ideas on what's happening and/or how to fix it?
Thanks,
John
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=394816#394816
Message 2
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| Subject: | Re: Eye Beam Mini LED / RF interference |
>
>
>Any ideas on what's happening and/or how to fix it?
Without more details on how it's made, I wouldn't have
a clue. Touch-sensitive switches are not well suited
to a strong rf/noise environment. Unless the product
was subjected to at least a rudimentary investigation
of it's vulnerabilities, anything we might attempt
is just throwing darts.
Bob . . .
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