Modifying a NASA LED tricolour

[nimbusgb]

I've sorted a modification to the NASA Tricolour LED masthead unit so that it is both an anchor light and a tricolour. In addition I have managed to do it with the standard two wires already up my mast for the existing masthead anchor light. Apply power 1 way - anchor light illuminates, switch polarity and the tricolour comes on instead. So no new wires to draw up the mast!

To do the mod I have had to aquire a 1m length of 90mm clear acrylic tubing which I need to part off into about 25 mm lengths and machine a small lip onto each end.

Anyone in Sussex ( Brighton, newhaven, Tunbridge Wells ) area prepared to do a bit of piece work with a lathe?

 

[Martin_J]

I will be interested to see if this makes the unit more weatherproof... and if you still plan to then mount it on the original single stalk. The original stalk can sometimes turn in the white plastic moulding when you add more weight to it!

Here is a link to a thread earlier in the week with my end result...
http://www.ybw.com/forums/showthread.php?t=264606

Good idea about the reverse polarity though - although I went the 3-core way since I already had two switches marked up on the switch panel.

 

[nimbusgb]

Additional weight about 50 grammes.

1 - Preventing the stalk turning - I drilled through white plastic, dribbled in a drop of zapagap ( gap filling superglue ) and popped in a small self tapper.

2 - Anchor light is an array of 3 3 watt luxeon star leds in parallel driven by a proper 330ma current limiting circuit. Current draw from 12v about 120 ma. Star Leds are arranged in a triangle around the main shaft giving all round white light. Sits below the tricolour not above.

3 - The 90 mm acrylic tube is to basically extend the overall height of the cover up 25mm.

The Nasa tricolour unit is protected against reverse polarity connection by a diode ( it also has a Zener diode to prevent voltage spikes getting into the unit this is standard on the units pc board not an addition ) so using the other method ( stacking a nasa anchor light ) could be done the same way. wire the positive of one to the negative of the other and visa versa. then when you feed the stack one way you'll have tricolour and the other anchor light. ( Provided of course someone can confirm that the anchor light also has a blocking diode. )

I've taken a few photos. Ill edit up a few of them and stick em up.

 

[Martin_J]

Thanks! I didn't try reverse polarity on either unit..

When I find pictures I'll post the ones of my modification as well. I am sure I mounted the tricolour as the higher unit. Being higher it lit up the wind indicator better. The cable was just fed through the lower unit.

 

[noelex]

Sounds like a great project.
3X 3Watt Leds under driven are a great way to generate lots of light.
The Luxon star is very old however there are far more efficient LEDs available
Say a Cree XP-G R5 would give you lots more light or the same light with much lower power consumption.

 

[nimbusgb]

I had a box with about 20 luxeons in it so I was just wanting to get rid of them. Any white leds would do. It was more the mechanical bits I wanted to sort out.

Playing around with the unit the cut off between the sectors appears to be pretty iffy. I must rig it up and have a look at it from a mile away to see what it is like in practice not on the desk top!

 

[Martin_J]

At least you can leave the upper tricolour pretty much in one piece. I had to chop the bottom off it and then drill straight through the circuit board in the NASA anchor light to be able to feed the wire through!

 

[Martin_J]

You are right about cut off... it looks bad on the photo but in practice (from about 100 meters away) the cut off seems okay.

What was strange though is when looking at it from 100 meters away as you walk around the marina. As other masts and shrouds get in the way you do appear to get twinkles of the wrong colour just briefly... it's odd.

 

[noelex]

I had a box with about 20 luxeons in it so I was just wanting to get rid of them. Any white leds would do. It was more the mechanical bits I wanted to sort out.

Playing around with the unit the cut off between the sectors appears to be pretty iffy. I must rig it up and have a look at it from a mile away to see what it is like in practice not on the desk top!

I can understand wanting to use up the luxeons . keep in mind a modern LED will produce 2 to 3X the amount of light with less heat and a larger viewing angle. This would solve the cut off problem.
If the idea works with the luxeons it would be an easy swap to something better.

 

[pappaecho]

I thought that LEDs like all diodes are unidirectional, so that reverse polarity would not work, as the diode would block the current flow.
Anybody explain to a simple chemist how his fix works??

 

[nimbusgb]

I can understand wanting to use up the luxeons . keep in mind a modern LED will produce 2 to 3X the amount of light with less heat and a larger viewing angle. This would solve the cut off problem.
If the idea works with the luxeons it would be an easy swap to something better.

You have misunderstood my posting. The cut off photo is of the tricolour as NASA supplies the unit. Nothing to do with my mod. NASA has used standard 5mm high intensity LEDS arranged in a circle.

My modification is to add an all round white light ( luxeons ) to act as an anchor light separately from the tricolour and is not intended to be and in fact can not be turned on at the same time as the tricolour.

 

[nimbusgb]

I thought that LEDs like all diodes are unidirectional, so that reverse polarity would not work, as the diode would block the current flow.
Anybody explain to a simple chemist how his fix works??

Quite simple really. Yes LED's only conduct in one direction and they block current flow in the other provided the voltage stays below the maximum rated reverse voltage ( they break down and 'blow' after that ).

LED's have a reverse voltage rating of around 5v so connecting 12v backwards to them leads to problems but if you add a blocking diode like a 1N4007 which is rated at 1000v reverse you prevent the LED seeing more than 30 millionths of an Amp. Insufficient to raise any voltage across it at all.

Circuit attached ....

If the supply is added at A and B with A positive then D1 conducts as does LED1. D2 however does not conduct so neither does LED2. Reverse the input supply and hey presto LED2 lights up and LED1 goes out.

It gets a bit more complicated because the NASA light has built in circuitry to regulate current and my LED driver also runs off AC but the basics still work. D1 conducts in one scenario and D2 in the other So any 2 devices connected in place of the led/resistor combinations could be selected by reversing the input polarity. ( Provided the forward current requirement of the device is below the operating current of the blocking diode, about 1 amp with an 1N4007 )

 

[noelex]

You have misunderstood my posting. The cut off photo is of the tricolour as NASA supplies the unit. Nothing to do with my mod. NASA has used standard 5mm high intensity LEDS arranged in a circle.

My modification is to add an all round white light ( luxeons ) to act as an anchor light separately from the tricolour and is not intended to be and in fact can not be turned on at the same time as the tricolour.

I assumed the cut off problems were with the anchor light. Is this correct?
3 Luxeons will struggle a bit to provide a bright enough light over the full 360 degrees.
A brighter LED with a larger viewing angle would be a better choice, but I understand you want to use what you already have.

 

[nimbusgb]

I assumed the cut off problems were with the anchor light. Is this correct?
3 Luxeons will struggle a bit to provide a bright enough light over the full 360 degrees.
A brighter LED with a larger viewing angle would be a better choice, but I understand you want to use what you already have.

Nope cut off challenge is on the red/green/white of the tricolour. You can see the orange bleed over section in the photo I attached.

The white luxeons are batwing radiators but you are right I'll add 4th although the radiation looks good all round at the moment. Plenty of light.

 

[noelex]

Nope cut off challenge is on the red/green/white of the tricolour. You can see the orange bleed over section in the photo I attached.

The white luxeons are batwing radiators but you are right I'll add 4th although the radiation looks good all round at teh moment. Plenty of light.

Ok, sorry, thanks for clearing it up.

 

[pcatterall]

So, for the simpletons among us ( who don't want to mess around with circuit boards and soldering irons) it seems that you can piggy back an anchor light on top and feed it with wires through the tricolour and its circuit board. An extra positive lead is required up the mast unless we go the 'techy route' ??

 

[nimbusgb]

So, for the simpletons among us ( who don't want to mess around with circuit boards and soldering irons) it seems that you can piggy back an anchor light on top and feed it with wires through the tricolour and its circuit board. An extra positive lead is required up the mast unless we go the 'techy route' ??

Can do, but the techy route, thanks to NASA is just a single DPDT switch, no circuit boards, no soldering, which is actually simpler than drawing a new wire up the mast! In the diagram the two lights are wired red to black. Depending on the DPDT switch position the relative light will illuminate. To turn off both lights either you have a centre off DPDT switch or just turn the 'nav light' cct breaker off. If you are fitting or have fitted conventional deck level 'high power' nav lights then just add a changeover switch to select deck level or masthead nav lights.

Having made it all simple I will now confuse you by saying that I have my nav lights wired to a rotary switch. 1 - Deck level Nav, 2 - Steaming ( which keeps the deck level navlights on since the engine is running and we are not concerned with power ), 3 - tricolour, then 4 - anchor. Just move the switch to the right position and the right lights come on, even I can't get the wrong combination of lights to show. ( Thinks, if I detect the oil pressure and gear position from the engine I can automatically set the steaming light too! )

 

[Martin_J]

I used three wires with two NASA units... but I did that because there had been no previous lights at the top of the mast. Also - to power a standard light 48ft up I would have needed at least 3 sq mm cables... LEDs work with a lot smaller cross sectional area cable.

If I had looked into the 1N4006 route then I might have done it with a single wire pair (although having two switches at the panel also directed me towards a 3-core solution).

I do like the idea of the polycarbonate tube around the assembly though to protect the NASA lights.

Sorry - we're off topic. The request was for someone who can do a little turning work...

And reply to posting above... if you detect engine on 'and' darkness then the lights will come on automatically!

 

[nimbusgb]

And reply to posting above... if you detect engine on 'and' darkness then the lights will come on automatically!

The Nasa units have diodes built in so no need.

and my anchor light already has a light sensor on it so I'm halfway there!

Still haven't got a machinist yet! Might have to go buy a lathe!

 

[Rogershaw]

This is how I mounted my NASA nav lights

Don't use polycarbonate tube as it will be damaged by the UV and will reduce the nav lights light output.