Bulb on indicators

[howardclark]

I will make new switch panels this winter and see some from people like Blue Sea with a stencil of a boat and LEDs showing the bulbs of Nav lights etc are working. I fancy concocting something similar. Anyone know the best way to wire this?

 

[bedouin]

I'm not sure whether the BlueSea type board shows whether the lights are working, or just whether they are switched on. The latter is easy - a resistor & LED in parallel. The former is a bit more complicated - taking a couple of turns of the (positive) wire round a read switch might work - but I've not tried it - otherwise its down to electronics...

 

[bryantee]

I have done two boats with light board indicators.A Nova 27 and a Rival 31. Took an ouline profile from the Brochure and my local sign writing shop did the profile on Black plastic with white outline.about £15 a throw with Ships name and details and a four position switch in the middle.We tried to get a bulb out system working with a relay on the neg.through a mini solenoid but the power requirements were too much.The steaming light is wired through the ignition and a solenoid with diodes to stop backfeeding to the stern light when using low level sailing lights.Any body want to see a photo of the finished job. and a wiring diagram send a pm with your e mail address.

 

[steve_cronin]

Do you mean....

something that tells you that the light is switched on or something that actually tells you that the bulb is (should be) alight? There is a difference. The first is just down to LED's between negative and the output of each switch - trivial , but the second requires some sort of continuity monitoring electronics like on some cars these days (BMW, Mercedes, Jaguar etc) - slightly complex but not that difficult.

Steve Cronin

 

[Forbsie]

I'm sure I had a Sierra years ago that had a diagram of the car and showed blown bulbs as well as open doors (sure I'm not imagining it). I would have thought that this could be doctored to do what you want.

<A target="_blank" HREF=http://www.arweb.co.uk/argallery/forbsie>My Project Pics</A>

 

[halcyon]

Yes they did fit them, together with low oil and water warning.

We fitted them to marine switch panels from around 88 till we gave up panels in 96. just a matter of comparing magnetic field round cable with a known value of the bulb, or bulbs.


Brian

 

[VMALLOWS]

I think it would be better to put the LED and resistor in SERIES! (about 220 ohm at 12v).

 

[VMALLOWS]

Magnetic field?... Sounds a complicated way of doing it. Why not just measure the current . Should only need a very small resistor in the feed to the light and one transistor plus zener. (or a dedicated chip which might be cheaper!).

 

[halcyon]

Thats were we started in the 80's, sounds cheap and simple, but is more trouble than it's worth. You can use around 50 turns around a reed switch, messy, but a DIY way.

This is why we went for measuring the current via magnetic field, same system as we us for the current shunts we supply the boatbuilders. Once you get into it, it's very simple and versatile.


re other post, average brightness on average LED at 12 volt us a 1K2 resistor, for a bright LED use 560R 1/2 watt.


Brian

 

[chippie]

I wonder if the experts can tell me whether tapping a wire off the return and through a bulb or LED to earth would work. The return wire would only have current through it if the main bulb had current through it.

 

[bedouin]

I think you'll find it works better with the resistor/LED combination in parallel with the bulb

The point being that by being in parallel, such a set up can only reflect the voltage, not the current, and so cannot indicate whether the bulb is actually working.

In order to determine whether the bulb is working you need to be able to detect current flow - which requires the sensor to be in series with the bulb. The easiest way probably being to detect the magnetic field generated by the DC in the wire.

Clearly wiring an LED and 220ohm resistor in series with the bulb won't achieve the desired result - except I suppose it could be used as a simple bulb/wiring test facility.

 

[bedouin]

I'm afraid it's not really practical.

Any simple optical indicator like that (LED or filament bulb) will drop a significant voltage (a typical LED is 2V) which will adversely affect the performance of the bulb being measured

 

[VMALLOWS]

The particular post I was replying to was refering to the use of an LED purely as an indicator that the switch was ON....hence the series connection. Agree with your 1.2K / 560 ohm figures........was late and I was thinking 5v.

 

[jollyjacktar]

Make a pretty panel

The best check is the MKI eyeball, uses no voltage, current etc other than that internally generated by the body. Otherwise accept the easy option of indicator LEDS to show switch positions [that is if you can not be bothered looking at the switch position itself or using light [internal in the toggle or such, indicating switches].

Why not get one of those nifty electonic kit set Christmas tree [LED]lights sets and mount it in your custom designed panels then when you switch it on you can have flashing lights and LED light chasers and things that look like a space craft Flash Gordon instument panel. It will look really impressive, entertain the guest and be apro-pro of nothing, but good fun.

 

[VMALLOWS]

Re: Make a pretty panel

Why not just look at the lights..........

Agree! was about to add the same comment when you beat me to it! Mind you, I do need to rig up something to remind me to switch the fridge off (or back to gas) when the engine stops..............7amps overnight is not good news.

 

[jollyjacktar]

Try a buzzy thing.

Had a similar problem, fitted a super bright LED to indicate the on switch position and a buzzy piezo thinghy that would make one hell of a din when my motor was switched off and thus not charging, ie on the the charge indicator light circuit for the alternator. Combimation of both was enough to remind me to turn off the fridge most of the time.

Now I find you can get some sort of electronic thing that electrically disconnects when voltage drops below a preset level and that then switches off all /or any appliance that is rigged to it thus preserving some starting votage in your battery [generally available for motor homes and such].

Still better to keep things simple and connect fridge in a manner that when you switch off the ignition [or its equivalent] then the fridge circuit is disconnected at the same time [possibly use a relay].
Good luck.