Forum Navigation
Please or Register to create posts and topics.

ELT Panel By Project45 Discussion

(Original thread started on 03-01-12 by Ron Rollo)

As your probably aware, I came up with an Emergency Locator Transmitter panel a few months ago. It was designed to be used with an FDS board. However, after a few things were pointed out by Alan and Eric T., I decided to do a redesign of the ELT Panel. Here is a photo of the old design. Nothing other than the toggle is changing on the face:

Ron 1120

 

The key to the ELT is the miniature locking toggle (which I did not have in version one) Unfortunately, I had to redraw the whole thing and nothing can be used from the old design. Therefore, for all those who purchased one of my ELT's just shoot me an email if you want the new version at no cost.

 

So while I was at it, I wanted to go ahead and model as much of the ELT as practical, but, using hardware logic! As we know, most of the simulator is modeled in software logic but I wanted to take on this little project using nothing but hardware to model the functions of the panel. It's the perfect panel to do this with because it really has nothing to do with the actual flight simulation. With that said, the ELT panel can be easily modeled in software logic and as a matter of fact, you can even have it set off if your sim detects a CRASH.

 

Here is what we can expect from the ELT panel from the pilot's point of view:

Ron 1121

 

Basically, the red LED will have three states:

 

ON = illuminated

OFF = flashing 80 times per minute

ARM = extinguished

 

On top of that, I will use a Sonalert Mallory alarm to be used when the toggle is raised to the "ON" position. This position WILL never be selected unless something very bad happened and you lived through it and the ELT did not set it self off while it was in the "ARM" position!

 

The fun part was picking out the hardware to make this work. I am using an ON-Off-ON toggle. So the question is how to get the center position to illuminate the LED?  And on top of that, make it flash?

 

The answer is a relay and a flasher. The relay can be found at Radio Shack. The Flasher is actually an automotive turn signal flasher. Both the relay and the flasher are designed to handle , you guessed it, 12 volts. Here is a photo of the new hardware:

Ron 1122

 

The power source is going to come from my Right Hot Bus. This drawing isolates the ELT panel and the ELT Sub Module. The circuit is still the same:

Ron 1123

 

(Posted by Will Sasse on 03-01-12)

Nice work Ron, there is getting less and less for us later arrivals to have to think about and solve!! How boring!  Is the Sonalert Mallory alarm to give you an audible alarm sound? If so does it replicate the distinctive ELT pulsating tone?

 

In practice, it may be advisable to use it just before something really bad is about to happen and you don't want to rely on the automatic sensor activating during the event, which has been known to occur.

 

(Posted by Shane Barnes on 03-01-12)

Cool Ron! Another area that is not modeled in FS but with a little work we can get something out of it. To me, these little "added" details make our builds more believable. All the small details add up to a nice "wow" factor.

 

Hey Will, "something really bad is about to happen" . . .

 

Seems like I recall someone posted a recording here in the forum of ATC traffic with an aircraft in a severe icing situation and at one point ATC requests that they go ahead and activate their ELT.

 

(Posted by Ron Rollo on 03-02-12)

Thanks guys, Eric and I were discussing this yesterday and never thought about activating it prior to the "something really bad event" happening.

 

Will, right now I am planning to use the Sonalert Mallory alarm. It is a steady tone. I would like to have something that sounds more like the real ELT but the question I have is does this sound only transmit over the emergency frequencies or also in the cockpit?

 

And yes, it is a minor detail but they do all add up to something incredible. I did some testing this morning and confirmed that the relay and the flasher work as I have them figured out in my head. Now for the really hard part......Finding the time to complete it.

 

Another thought for you guys, I am going to build what I am going to call the "ELT Sub Module". Because the panel is so small, all of these components will not mount to the back side of it like I would do with a larger panel. So I am building a module that these things will attach to and it will be mounted to the inside wall of the center pedestal.

 

(Posted by Alan Norris on 03-03-12)

How does it get power from the right side hot bus? I am assuming you are somehow splitting your panels into those fed from the right and left side buses. This may not be the thread to explain how you are wiring your sim but perhaps in a separate post. Also I'm assuming if one was to purchase the separate module we would have to change the LED on our existing ELT panels for a 12v one.

 

(Posted by Ron Rollo on 03-03-12)

Alan, You would have to switch out the LED for a 12 volt LED. I have 20 of them on the way.

 

As for the hot bus, the main idea is that the ELT receives power at all times even if all of the airplane is powered down or shot down. The only thing that will kill power to the ELT is cutting the power to the power strips that power up the power supplies.

 

Here is a quick picture of the power supplies the hot buses and the ESS buses:

Ron 1124

The left and right hot buses are directly above the power supplies.

 

(Posted by Will Sasse on 03-04-12)

Normally, the sound only transmits over the frequency, not in the cockpit. In a previous job we used to set 121.5 at shutdown just to check we weren't accidentally broadcasting. That was a while ago, and things might have changed to reduce false alarms of epirbs going off in someones duffle bag on the way home!!! The number of beacon tracks that end up at some pilots garage along way from any airplane....

 

PS: I like your electrical bus system. Hadn't thought of that. Are you splitting the cockpit from side to side, or is it just different elements on different PSU's?

 

(Posted by Ron Rollo on 03-09-12)

I completed my revised ELT panel and Sub Module. It actually works just as I had planned!  This was exciting for me because I have never designed a circuit on paper and then built it. Having the wiring diagram schematic close by was a must because during the build process, I had wires going every which way. Even after it is complete, it is still hard to follow the current flow.

 

Here is a photo of the ELT (Emergency Locator Transmitter) and my Sub Module completed and ready to install:

Ron 1125

 

Here we have everything mounted and ready for testing. The mini toggle is a big improvement over the other one I had. It is a locking toggle and it is a double pole. I could not have created this circuit without the double pole toggle. Also, I am using an automotive flasher relay. So when it is flashing, it sounds like my turn signal has been left on. Fortunately for us, the normal position for the switch to be in is ARM, which means nothing is happening. No light and no sound:

Ron 1126

 

Everything looks and works good. Although the Sonalert is not the correct sound for the ELT, it will work for me. As we stated before in this thread, the ELT will never be switched to the ON position unless something really bad is getting ready to happen:

Ron 1127

 

So to summarize my ELT red LED, it is off when it is in the ARM position. It is flashing 80 times per minute in the center position which is the OFF position. And it is on solid in the ON position. Also while in the ON position, the Sonalert is activated.

 

It is modeled as close as I care for it to be with the exception of one thing. It will not flash five times per second which indicates that the monitor unit coin cell needs replacement. I promise I won't miss that!

 

(Posted by Alan Norris on 03-10-12)

One thing that has always puzzled me is that we use machine screws (your dummy Dzus fasteners) to attach the panels to the center and TQ consoles yet they are screwed into wood.

 

I am using brass inserts but you have to be very accurate where you drill the the holes for them:

Alan 59

You can find them HERE

Great looking ELT module!

 

(Posted by Ron Rollo on 03-12-12)

I actually thought of using these inserts and ran into the same issue with alignment. So I chose to just tap a hole into the bare birch. If you in fact strip out the hole, don't worry, drop a couple drops of wood glue in the hole.

 

(Posted by Will Sasse on 03-13-12)

Instead of a car blinker relay, could you use a blinking circuit from your local electronics supplier?

 

At least then you might not have the turn signal sound.

 

(Posted by Ron Rollo on 03-13-12)

My first stop was my local Radio Shack store. They are almost worthless unless you want a cell phone or a remote control helicopter!  I am happy with what I have because 99.98% of the time, it will be set to the "ARM" position. One day I may revisit this and build it for a third time after one of you guys find something that works even better.

 

If you have any question on the ELT panel, it's function or would like to add your thoughts, please post here.


Comments are closed, but trackbacks and pingbacks are open.