Trim Selector Switch & Indicator

[n82rb]

Originally Posted by GalinHdz

If you notice that is exactly what the panel switch does and for the same reasons. It connects the ground to the pilot flying while disconnecting the ground for the pilot not flying. The only thing I added now was a switch position indicator. Like you say, simple and effective.

I am curious. How would you do it with a couple of resistors?

actually since you are using bi-colored leds i would spend and extra buck for a 7800 series regulator to get a stable voltage supply and then go with a current limiting resistor.

bob

[rapid_ascent]

Well it's not exactly poof, but it sounds like you have figure it out.

[PCHunt]

Just to be "Cheeky", , my solution would be to have a manual trim knob in between the seats that either pilot could reach, but only one pilot at a time could operate..........

Sorry, couldn't resist!

[leok]

The resistor solution works fine if you set the resistor value to limit the current appropriately at full regulated voltage. The LED will be somewhat dimmer at a lower voltage. As an aside, the LED "dimness" could also serve as a warning that the buss voltage is dropping for a poor mans charging system monitor.

To be a little more elegant a linier voltage regulator such as this one could be used at $2 each and small enough to be part of the wire harness,
https://www.digikey.com/product-deta...NOPB-ND/363564
to first regulate the voltage to 5V and then a fixed resistor to set the forward voltage. Or just choose a linier regulator with a 2V output. They are out there. I'm just too lazy to look up the part number. This way voltage changes, won't change the brightness.

One further refinement is to add a pot into the circuit to dim the indicators for night flying. Pots are not linier as far as light output, but do a nice job dimming LEDs. If the right range is chosen, full bright/dim will be the extremes of the pot. (Or just add a switch to insert a fixed resistor for bright/dim control)

[8 Builder]

For those of you who are not electrical engineers and have a G3X touch system; Garmin makes the GDL 27. It takes care of prioritizing the pilot over the co-pilot switch inputs. For guys like me who have NO electrical savvy, this is of course the way to go, although pricey. It does a bunch of other stuff too and makes a newbie builder very happy.

[GalinHdz]

Originally Posted by leok

To be a little more elegant a linier voltage regulator such as this one could be used at $2 each and small enough to be part of the wire harness,
https://www.digikey.com/product-deta...NOPB-ND/363564
to first regulate the voltage to 5V and then a fixed resistor to set the forward voltage. Or just choose a linier regulator with a 2V output. They are out there. I'm just too lazy to look up the part number. This way voltage changes, won't change the brightness.

One further refinement is to add a pot into the circuit to dim the indicators for night flying. Pots are not linier as far as light output, but do a nice job dimming LEDs. If the right range is chosen, full bright/dim will be the extremes of the pot. (Or just add a switch to insert a fixed resistor for bright/dim control)

That is basically what I did but I went with a small adjustable linear regulator so I could set a specific voltage based on the LED I selected. I actually set the voltage at 2.17v. At 2.17v both colors show up perfectly and they are dimmed enough that I don't have to worry about night flying or burning them out. Other than that, your and my approach to the situation are the same.

[leok]

Originally Posted by GalinHdz

That is basically what I did but I went with a small adjustable linear regulator so I could set a specific voltage based on the LED I selected. I actually set the voltage at 2.17v. At 2.17v both colors show up perfectly and they are dimmed enough that I don't have to worry about night flying or burning them out. Other than that, your and my approach to the situation are the same.

No problem, didn't mean to imply your solution was any different.

My response was for those who don't know much about linear regulators. They are available in adjustable form where a few added components fix the output voltage. This requires a small circuit board to connect everything. That appears to be what you have with an adjustable resistor to set output voltage.

They also come in fixed output where the "extra components" are in the IC. For these an additional resistor can be used in series to make the final adjustments.

For low current applications like the LED indicator lights no heat sink is needed. The package is very small. The electronics are very simple. If dimming is a goal, an added pot will do the job nicely.

I have two 5V linear regulators in my system. One drives the Arduino which controls the heater servos. The other provides current to a small MP3 player. The MP3 player draws more current and so required a small heat sink to support the output.

In any case, nice application of current regulation and LED indicators in your aircraft.

[GalinHdz]

Oh no, I didn't take it as negative at all. There are more than one way to skin a cat and we sure skinned this one.