Designing a system for controlling the lights at a private airfield
- Thread starter Rabbit H
- Start date
Guys, I appreciate your interest in this project but after further research into it, it seems to me that it's too complicated of a project for a "hobbyist" forum. I thought that it would be a project worth trying but second thoughts have me thinking that there are just too many unknown variables (such as atmospheric anomalies that alter or disguise the squelch breaks that we're trying to detect and decode), coupled with the likelihood that there aren't very many on this forum who are familiar with airport lighting systems and how they're controlled from the cockpit.
Sooooo, I'm gonna pull the plug on this idea. I appreciate the interest that y'all showed and I hope to work with y'all again !
Harvey
Sooooo, I'm gonna pull the plug on this idea. I appreciate the interest that y'all showed and I hope to work with y'all again !
Harvey
It's more about the output format and the response of the receiver than it is about being 'aviation' related. I'm ASMEL IA CFI and have used such systems on occasion so do know how they work.
I do see where the owner of Hamtronics passed away, but try as I might, I can not find anything that says Hamtronics is out of business. Even if it is I still think your best bet would be to try and get your hands on an R123, then *you* don't have to try and create a detector circuit that matches up with the receiver output characteristics.
I do see where the owner of Hamtronics passed away, but try as I might, I can not find anything that says Hamtronics is out of business. Even if it is I still think your best bet would be to try and get your hands on an R123, then *you* don't have to try and create a detector circuit that matches up with the receiver output characteristics.
We submitted an order on Friday for a commercially-built receiver-decoder unit. (What I've been calling a "PCL Box".) This RF unit, admittedly the most difficult part of a pilot-controlled airport lighting system, will make our plans much easier to implement now that we're not trying to build our own! The receiver-decoder unit should arrive around the end of this month which will give me about 3 weeks to design and build the load-switching circuits. We're currently working on what we want the decoder to turn on, when, and for how long.
Harvey
Ylli,
We share many of the same ratings.
Harvey
Ylli,
We share many of the same ratings.
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The above drawing will give you an idea of what we're trying to accomplish. The three functions that we're switching are the 1250w rotating beacon, the two 60w obstacle lights on top of the beacon tower, and the two 100w Windsock / Airmarker lights. All lights are 110vac, are located on the tower, and are activated by individual tower-mounted relays or contactors with 24vac coils. The control box is located 150ft away in a hangar. In addition to the control circuits, the control box will contain the RF Receiver/Decoder unit that will allow inbound pilots to activate the tower's lights via "mic clicks".
ANOTHER WAY OF EXPLAINING THE ABOVE (Added 22 June 2018)
A. Upon receiving and decoding a valid request from an aircraft, the Receiver/Decoder’s output relay (L-854-R3) energizes (changes state) for 15 minutes. (R3’s output is a set of dry SPDT contacts and its output duration can be set to 1, 15, 30, or 60 minutes.) This relay will initiate the tower's Start-Up sequence. The purpose of the sequential turn-on and turn-off cycles are (1) to reduce the large current inrush by spacing apart the three light startups, and (2) it adds an interesting effect. The beacon’s contactor will be closed at the start of this “enable gate”.
B. 3 to 5 seconds later (adjustable during system setup) the windsock/airmarker’s relay closes, completing the start-up sequence.
C. The shut-down sequence automatically starts 6-12 minutes later (adjustable during system setup) by opening the windsock relay
D. The beacon’s contactor opens after another 3 to 5 seconds (again, adjustable during system setup) and the obstacle lights relay closes until the end of the 15 minute cycle. This completes the shut-down cycle and resets the system for the next valid request from the receiver/decoder.
It's been suggested that I consider activating the tower's lights via adjustable time-delay relays. However, a quick look at the relays now available have my head spinning! I'm not sure if I need to look at “standard”, delayed-make, one-shot, or interval-delay relays. Also, should I get the fancy (and expensive) knob-adjustable P&B relays or the smaller (and cheaper) "encapsulated" relays?
Harvey
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The L-854 Receiver/Decoder from Rural Electric arrived on May 21st and it is immediately apparent that they have manufactured a quality product. (Attachments posted with Rural Electric's permission. Their website can be seen at www.ruralelectric.com)
Harvey
Harvey
Attachments
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Now I need to design and build the timing circuits. Unfortunately, my attempts so far have resulted in waaayyyy overcomplicated designs! Somehow, a simple circuit design eludes me.
My designs have been based on common (readily available) mechanical time-delay relays. I know that these are archaic things but I prefer them over a microprocessor-based design because I'm the kind of guy whose VCR flashed 12:00 throughout the entire 1980s! Besides, my wife and I just purchased a new clothes washer to replace our worn out one that gave us over 20 years of dependable service. Unfortunately, the new washer has yet to go two months without needing its motherboard replaced! It's still under warranty so the repairs have been at no cost to us but the question that keeps nagging me isn't what it's going to cost us after the warranty period runs out but...
WHY THE @$*&!!! DOES A WASHING MACHINE NEED A MOTHERBOARD???
Harvey
My designs have been based on common (readily available) mechanical time-delay relays. I know that these are archaic things but I prefer them over a microprocessor-based design because I'm the kind of guy whose VCR flashed 12:00 throughout the entire 1980s! Besides, my wife and I just purchased a new clothes washer to replace our worn out one that gave us over 20 years of dependable service. Unfortunately, the new washer has yet to go two months without needing its motherboard replaced! It's still under warranty so the repairs have been at no cost to us but the question that keeps nagging me isn't what it's going to cost us after the warranty period runs out but...
WHY THE @$*&!!! DOES A WASHING MACHINE NEED A MOTHERBOARD???
Harvey
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No, I just missed your last post.
For what?
I though the item you bought included everything you needed.
Howdy, I built a prototype of one several years ago using an RWS-123 module from Wenshing Electronics.
http://www.wenshing.com.tw; http://www.rf.net.tw I don't know current status.
It's output went to an MC9S08SH4 (I use the Freescale / NXP 9S08 series).
It was working fine, but the project primary was "erratic" and the project stalled.
http://www.wenshing.com.tw; http://www.rf.net.tw I don't know current status.
It's output went to an MC9S08SH4 (I use the Freescale / NXP 9S08 series).
It was working fine, but the project primary was "erratic" and the project stalled.
KeepItSimpleStupid
- Joined Mar 4, 2014
- 5,088
You should look at the Idec smart relay. e.g. http://us.idec.com/Catalog/ProductD...&FamilyName=Family&SeriesName=FL1F_SmartRelay This may not be the exact model to use. There are simulators to use before you buy.
Howdy Crutschow and others,
The nighttime activation of runway lights at unattended airfields is typically done by an inbound pilot clicking his or her communications radio's push-to-talk mic button either 3, 5 or 7 times within a 5 second period*. This will usually turn on the runway lights for a preset time and then reset (extinguish the lights) until activated again by either the same aircraft or another one. While there are some exceptions, the standard on-time is 15 minutes which will usually give an inbound pilot enough time to visually locate the runway, land, and taxi clear of it before the lights automatically extinguish. Of course, if more time is needed, the pilot can reset the 15 minute period by transmitting the 3, 5 or 7 mic clicks again. This system permits around-the-clock runway availability for those airports that are not staffed at night but without resorting to keeping the lights activated all night.
{*Note: The purpose of the three activation settings ("3, 5, or 7 clicks") to activate the system (as opposed to having just one) is for system versatility. Some airports are set up with more than a simple on-off control of its runway lights. One, two, or three steps of brightness is sometimes available or there may be additional lights available such as "lead-in strobes". The three steps of activation allow the pilot to choose what he or she wants or needs. Therefore, Pilot-Control-Lighting boxes can either be simple on-off devices, or get quite complicated depending on how many functions are desired.}
My original post was a naïve desire to homebuild a simple system that would meet our airport's needs. Such a system can be divided into two separate parts: a Receiver/Decoder, and a lighting controller. The receiver/decoder would listen for the FAA-standardized 3, 5, or 7 mic clicks but would also prevent false activations due to spurious RF noise. The decoder would take a valid request and activate the lights that the airport authority or owner has provided, be it multiple levels of brightness or multiple lighting functions. The inexpensive "hobbyist grade" Hamtronics and Ramsey kits that I mentioned in the opening paragraph of this thread solved the receiver/decoder part but they're no longer available. Therefore, I purchased a Model 854 Airfield Lighting Receiver-Controller from Rural Electric. (A designer and builder of professional airfield lighting control systems.) One output of the RE854 will be used to initiate the turn-on and turn-off sequences pf our airfield lights.
So now it's up to me to build the control circuits that the RE854 will activate. These lights, and their desired sequencing was spelled out in post #28 of this thread. While I undoubtedly could've designed such a "sequencer" in my sleep during my youth, it doesn't seem to be all that easy 50 years later. That's why I turned to AAC.
Harvey
The nighttime activation of runway lights at unattended airfields is typically done by an inbound pilot clicking his or her communications radio's push-to-talk mic button either 3, 5 or 7 times within a 5 second period*. This will usually turn on the runway lights for a preset time and then reset (extinguish the lights) until activated again by either the same aircraft or another one. While there are some exceptions, the standard on-time is 15 minutes which will usually give an inbound pilot enough time to visually locate the runway, land, and taxi clear of it before the lights automatically extinguish. Of course, if more time is needed, the pilot can reset the 15 minute period by transmitting the 3, 5 or 7 mic clicks again. This system permits around-the-clock runway availability for those airports that are not staffed at night but without resorting to keeping the lights activated all night.
{*Note: The purpose of the three activation settings ("3, 5, or 7 clicks") to activate the system (as opposed to having just one) is for system versatility. Some airports are set up with more than a simple on-off control of its runway lights. One, two, or three steps of brightness is sometimes available or there may be additional lights available such as "lead-in strobes". The three steps of activation allow the pilot to choose what he or she wants or needs. Therefore, Pilot-Control-Lighting boxes can either be simple on-off devices, or get quite complicated depending on how many functions are desired.}
My original post was a naïve desire to homebuild a simple system that would meet our airport's needs. Such a system can be divided into two separate parts: a Receiver/Decoder, and a lighting controller. The receiver/decoder would listen for the FAA-standardized 3, 5, or 7 mic clicks but would also prevent false activations due to spurious RF noise. The decoder would take a valid request and activate the lights that the airport authority or owner has provided, be it multiple levels of brightness or multiple lighting functions. The inexpensive "hobbyist grade" Hamtronics and Ramsey kits that I mentioned in the opening paragraph of this thread solved the receiver/decoder part but they're no longer available. Therefore, I purchased a Model 854 Airfield Lighting Receiver-Controller from Rural Electric. (A designer and builder of professional airfield lighting control systems.) One output of the RE854 will be used to initiate the turn-on and turn-off sequences pf our airfield lights.
So now it's up to me to build the control circuits that the RE854 will activate. These lights, and their desired sequencing was spelled out in post #28 of this thread. While I undoubtedly could've designed such a "sequencer" in my sleep during my youth, it doesn't seem to be all that easy 50 years later. That's why I turned to AAC.
Harvey
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The output from the RE854 is a set of dry SPDT contacts that change state when a pilot's request has been received and verified (decoded). This output automatically resets after 1, 15, 30, or 60 minutes
The sequence that I laid out in post #28 is both the turn-on and turn-off sequence in that the lighting system will turn-on, run for approximately 15 minutes, and then automatically turn-off. (i.e. they're not individually-activated.) However, while the turn-on and shut-down sequences aren't mirror images of each other, they are similar. Once triggered by the 854, the turn-on sequence will activate and run for a set period and then automatically shut down with a similar sequence.
Note that after activation, the 854's output relay automatically resets after 1, 15, 30, or 60 minutes which is switch-selectable during system setup.
It should be noted that if the RE854 receives an additional request before a currently-running turn-on/turn-off sequence ends, it should not reset the system back to the beginning for a new turn-on sequence but should simply extend the already-running "on" time. I believe that the RE-854 is already set up to do this.
Harvey
The sequence that I laid out in post #28 is both the turn-on and turn-off sequence in that the lighting system will turn-on, run for approximately 15 minutes, and then automatically turn-off. (i.e. they're not individually-activated.) However, while the turn-on and shut-down sequences aren't mirror images of each other, they are similar. Once triggered by the 854, the turn-on sequence will activate and run for a set period and then automatically shut down with a similar sequence.
Note that after activation, the 854's output relay automatically resets after 1, 15, 30, or 60 minutes which is switch-selectable during system setup.
It should be noted that if the RE854 receives an additional request before a currently-running turn-on/turn-off sequence ends, it should not reset the system back to the beginning for a new turn-on sequence but should simply extend the already-running "on" time. I believe that the RE-854 is already set up to do this.
Harvey
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