Lighthouse controller

Hello

I'm all new to Arduino, but found it as an easy way to get the right light characteristic for a lighthouse.

The project will be mounted in a box, in a actual lighthouse to control the light and needs to be reliable enough to work over the long nothern winter, where access to the lighthouse is limited.
So I got som questions to get me in the right direction...

  • What board is best for a "live" project? I now got a Uno rev. 3 and a Velleman VMA400 relay-card to experiment with, but I'm thinking about the reliability of the jumper-cables, is another card better where i could solder the cables on?
  • To power the board I was thinking a 12v power supply, to have the possibility to use a lightbulb to raise the temperature in the box and keep moisture out during winter, but when reading about it, it seems 12v might be bad choice for the boards and that 7-9v would be better, especially during months and months of continous operation. Any thoughts?
  • For redundancy I'm thinking of having two boards, sending a 'HIGH' output from the primary board to an input on the secondary, if boards 1 would fail, board 2 would loose it's 'HIGH' input and start instead. Would it be a reasonable approach or is it a better way to do it?

Thanks in advance!

To save energy, use a logic type N channel MOSFET. Relay coils do consume some current...
12 volt and a good buck converter is preferable in front of waisting energy in linear regulators.
Solar panels and charging can do a good job....
Giving controller 1 and 2 different start up time that security is likely a possible way to go.
'

What board is best for a "live" project? I now got a Uno rev. 3 and a Velleman VMA400 relay-card to experiment with, but I'm thinking about the reliability of the jumper-cables, is another card better where i could solder the cables on?

It's hard to make suggestions if we don't know the specs. I would expect a lighthouse to be dry and at least partly heated (by the light waste heat), so the conditions aren't that extraordinary. But as I haven't ever driven a lighthouse myself I may be completely wrong.

To power the board I was thinking a 12v power supply, to have the possibility to use a lightbulb to raise the temperature in the box and keep moisture out during winter, but when reading about it, it seems 12v might be bad choice for the boards and that 7-9v would be better, especially during months and months of continous operation. Any thoughts?

The linear regulator on the UNO board "burns" the 7V (from 12V to the internal 5V) into heat, so the thermic stress is considerable. 7 - 7.5V are much better. Or use a board with a switching regulator (DC/DC converter) there the input voltage isn't that relevant.

For redundancy I'm thinking of having two boards, sending a 'HIGH' output from the primary board to an input on the secondary, if boards 1 would fail, board 2 would loose it's 'HIGH' input and start instead. Would it be a reasonable approach or is it a better way to do it?

That way you catch only the simplest hardware failures (which are quite seldom BTW). If you really think that a redundant solution is necessary (I have serious doubts) use a system where each board is able to detect the output status (for example, does the light have power) and react if it detects that the state doesn't reflect the expectations. Such systems quickly get very complex, often you need three systems to build a quorum. What requirements do you have? Is the rest of the system comparably redundant (what happens if the light bulb fails, what happens if you have no power, what happens if you have a short circuit, etc.)?

What is the worst case senario if all boards fail?

Unattended for months means the possibility of failure.

Board: Nano or Pro Mini, properly soldered on a piece of perfboard. Much more reliable than the Uno as there are no wiggle connectors involved.

Power supply: 12V or whatever for your light bulb; buck converter to supply 5V to the Arduino (why that 7-9V? You got that from outdated tutorials maybe? Next you tell us you may want to use the barrel jack for power!).

Are you using battery? If so how are they going to last for months? Putting the Arduino to sleep during the day helps but probably insignificant compared to the power use of a self respecting lighthouse. The idea of leaving it unattended for months makes me believe this is a real life project, not for a model railway setup or so.

It is hard for me to say whether two boards increase reliability. The changeover has to be taken care of reliably, or that becomes the weak link. Having an extra board also means there's one more part that could fail - this is why modern aircraft have only two engines, less risk of an engine breakdown. It also implies that you expect the rest of the hardware to be more reliable than the Arduino board itself, which I think is unlikely. I'd guess it's the lens rotation mechanism, light bulb, and the battery in that order that are the most likely to fail. Maybe it's the lighthouse construction itself even that should be in that top 3, as that is what's exposed to the rigors of weather.

Hi,
Welcome to the forum.

Please read the post at the start of any forum , entitled “How to use this Forum”.
OR
http://forum.arduino.cc/index.php/topic,148850.0.html.

Limited access?
How will it be powered?
What is the actual application, a safety beacom?

Thanks… Tom… :slight_smile:

Thanks for all your responses!

I will try to clarify the nature of the project and answer all the questions.

A friend of mine has bought an decomissoned lighthouse from the Swedish Maritime Administration that he is renovating. The lighthouse is located on an island off the coast and due to bad weather, ice and the dark northern winter is unaccessible for a few months a year.

The lighthouse has been dark since 2007, but a couple of years ago i constructed a simple solution with a solarpanel, a car battery, twighlight sensor and a 12v car led bulb to light it up during the dark hours. However, without correct permission it could only be a fixed light.

Now the idea is to seek permission to get the old character back and light it as an "occas" light, ie occasionally. This means that it could for example be dark due to technical problems.
Last year he got mains power back into the lighthouse and a new feeder cable was laid out to the island (due to a youth hostel and a bird observatory also on the island, open during summer) so power will not be an issue, unless a total blackout would occur.
The cheap car led-bulb will be changed to a 230v bulb with the right color temperature, but will not be as bright as the original bulb, seen in the background on the image above.

It's hard to make suggestions if we don't know the specs. I would expect a lighthouse to be dry and at least partly heated (by the light waste heat), so the conditions aren't that extraordinary. But as I haven't ever driven a lighthouse myself I may be completely wrong.

There is no additional heat in the lanternine except the small amount that the bulb would produce, that would not be enough to heat even the inside of the lens, unfortunately. So the surronding temperature could range from -30°c to +30°c...

The linear regulator on the UNO board "burns" the 7V (from 12V to the internal 5V) into heat, so the thermic stress is considerable. 7 - 7.5V are much better. Or use a board with a switching regulator (DC/DC converter) there the input voltage isn't that relevant.

Power supply: 12V or whatever for your light bulb; buck converter to supply 5V to the Arduino (why that 7-9V? You got that from outdated tutorials maybe? Next you tell us you may want to use the barrel jack for power!).

Ok, so your tip about the dc/dc converter sounds good. As I said, I'm new to this so tips like this is really valuable.
And yes, I was considering using the barrel jack! :wink:

Board: Nano or Pro Mini, properly soldered on a piece of perfboard. Much more reliable than the Uno as there are no wiggle connectors involved.

Thanks, sounds like a solid coice. I see there's even a version of the nano with temperature- and light sensors built in, wich would help since I need a new twighligt sensor to turn the light on at dusk.

That way you catch only the simplest hardware failures (which are quite seldom BTW). If you really think that a redundant solution is necessary (I have serious doubts) use a system where each board is able to detect the output status (for example, does the light have power) and react if it detects that the state doesn't reflect the expectations. Such systems quickly get very complex, often you need three systems to build a quorum. What requirements do you have? Is the rest of the system comparably redundant (what happens if the light bulb fails, what happens if you have no power, what happens if you have a short circuit, etc.)?

It is hard for me to say whether two boards increase reliability. The changeover has to be taken care of reliably, or that becomes the weak link. Having an extra board also means there's one more part that could fail - this is why modern aircraft have only two engines, less risk of an engine breakdown. It also implies that you expect the rest of the hardware to be more reliable than the Arduino board itself, which I think is unlikely. I'd guess it's the lens rotation mechanism, light bulb, and the battery in that order that are the most likely to fail. Maybe it's the lighthouse construction itself even that should be in that top 3, as that is what's exposed to the rigors of weather.

What is the worst case senario if all boards fail?
Unattended for months means the possibility of failure.

You all got the point there, the Arduino is probably not the weakest link in this project.
The power source may fail, the power supply to the board, the realy controlling the flashes or the lightbulb itself. I should probably worry about those things instead!
If a link in the chain would break, it's not a issue other than my pride and that the lighthouse might be dark for a couple of months, it has no real importance for the navigation at sea any more.
Regards!

Living in Sweden Your project is special.
How faar away is it to use the old, reliable technich?
What's the name of the light house?

Railroader:
Living in Sweden Your project is special.
How faar away is it to use the old, reliable technich?
What's the name of the light house?

Tack!
None of the old tech is left, and it was because of technical problems it got dark in 2007, then they just decomissioned it instead of fixing it...
The name i Stora Fjäderägg. (Large Featheregg for our english speaking friends.)

Tack för Ditt svar. Thanks for Your reply.
Technical problems doesn't, likely, mean that the entire installation had fallen into pieces. What about manufacturing the broken parts? There are plenty of Youtubers that possibly would stand up.
Sorry, that name of the lighthouse is new to me. Where on the map would it be?

This should give a bit more info

https://www.instagram.com/stf_stora_fjaderagg/?hl=en

https://www.google.com/search?q=Stora+Fjäderägg&client=firefox-b-1-d&sxsrf=ALeKk02clrexBTK1oHrSxgjE9YAoH9vQ3w:1612305190136&lr=lang_en&sa=X&ved=2ahUKEwionYLxoMzuAhXSsZ4KHfyuDkkQuAF6BAgFEDA&biw=1144&bih=608

Tack! Thanks!
What is broken in the original equipment? Any knowledge?

I don't have much to add other than to request pictures of the lighthouse and it's workings, a write up of the project once it's done and an update on it's reliability after the first season.

Check reply#6 and the links given in #10

When talking about heating, we normally don't mean "ouch, that's burning!" but more like a few degrees above ambient. The latter is more than enough to keep moisture out of your electronics - as long as the temperature inside the enclosure is above ambient you're fine.

Though with temperatures of -30C you have to start worrying about the temperature rating of your parts, many of which are rated 0-85C only. A little heater may be in order, there are 50-100W space heaters available that are designed to keep a storage cabinet warm (i.e. well above ambient), or even a 5-10W resistor could work wonders to keep your electronics within rated temperatures.

Lightning may be another concern, that light house kinda resembles a huge lightning rod...

In general solid state electronics are very reliable, provided they are operated within specifications. The latter is where your engineering comes in play.

A very interesting project, all in all!

Can't tell for sure but it looks like the lens does not rotate. If the lens does not rotate then your job just got much easier.

What is the flashing pattern?

No evidence of a lamp changer that I could see (changes bulbs when a lamp burns out) (holds 3 to 6 lamps depending on lamp size)

How many watts/amps does the lamp draw?

There are some LED bulbs that are starting to show up for use in lighthouses/Fresnel lens

You could maybe add a burned out lamp alarm

It also looks like the Keepers Quarters could be possibly rented out to visitors, maybe work a deal with the local Hostel for management (help defer some of the costs, some people like to stay in historic lighthouses.

Build a simple website for the lighthouse, many low cost ways to do that, just a bit of history and a few pictures to start.

Good luck

  1. You want to heat the board to keep bad weather away

  2. You want to use DC/DC converter instead of linear to reduce heat produced

      1. = WTF?

SMD linear regulator is heating directly your circuit board - what better you can get?

SMD linear regulator is heating directly your circuit board - what better you can get?

Linear regulators tend to fail if they have to burn that much power for a longer period. So if you want your board to live longer you should go with a DC/DC converter. To hold the temperature above 0°C a separate heater may be good choice. As already noted above, such a heater doesn't have to be a big energy waster.

Thanks for all your responses!

I will try to answer the below.

When talking about heating, we normally don't mean "ouch, that's burning!" but more like a few degrees above ambient. The latter is more than enough to keep moisture out of your electronics - as long as the temperature inside the enclosure is above ambient you're fine.

Though with temperatures of -30C you have to start worrying about the temperature rating of your parts, many of which are rated 0-85C only. A little heater may be in order, there are 50-100W space heaters available that are designed to keep a storage cabinet warm (i.e. well above ambient), or even a 5-10W resistor could work wonders to keep your electronics within rated temperatures.

Lightning may be another concern, that light house kinda resembles a huge lightning rod...

In general solid state electronics are very reliable, provided they are operated within specifications. The latter is where your engineering comes in play.

A very interesting project, all in all!

Yes, that's my thought as well. Your idea of a resistor is nice. I was thinking about a few cm of powerful led-tape mounted on a big piece of aluminium, but a resistor might be easier because the more powerful led-tapes I got are all 24volts...
Lighting will not be an issue. The lighthouse has i lightning rod that has kept it safe for over 100 years.
Thank you!
Since I will need both a temperature- and a light sensor, would it be a good idea to buy the Nano BLE Sense with the sensors built in or should I go with external sensors? Any pros or cons?

Can't tell for sure but it looks like the lens does not rotate. If the lens does not rotate then your job just got much easier.

What is the flashing pattern?

No evidence of a lamp changer that I could see (changes bulbs when a lamp burns out) (holds 3 to 6 lamps depending on lamp size)

How many watts/amps does the lamp draw?

There are some LED bulbs that are starting to show up for use in lighthouses/Fresnel lens

You could maybe add a burned out lamp alarm

No, the lens is not rotating, the light only flashes.
The character was LFl(3) WRG 20s. Now it will be only white light.
Originally it was 2 1000W 120volt lamps and two 40W 10,3volts as backup.
Yes, I'm thinking about ways for a alarm like that and maybe an automatic lampchanger if a bulb burns out.

Linear regulators tend to fail if they have to burn that much power for a longer period. So if you want your board to live longer you should go with a DC/DC converter. To hold the temperature above 0°C a separate heater may be good choice. As already noted above, such a heater doesn't have to be a big energy waster.

Yes, a resistor or a piece of led-tape as mentioned above sounds like a better alternative at this point!

What do You give priority to? A light house working as reliably as possible or “playing” with the control stuff, Arduinos…?

Old fashioned thermostats have their advantage, and their life time. Sophisticated stuff, Arduinos, temp sensors, likely have a long life but are vulnerable regarding power, and some more.

This Forum has a lot of knowledge but there is also an amount of playing, intelligent, scilled but ignorant people guessing.