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The current is quite low. For the headlamps I guess < 25mA. But have not seen the spec of the Led's. So almost any diode will do. A 1N4001 would be way over the top but are easy to get. If you are ordering from Rapid, see what they have got at >100mA.

I am using BAW62 because I have a load of them. 1N4148 also OK Both of these rated at 150mA

As I say most will be OK
 

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I threw a N4004 diode, a single resistor and 4 superbrite Leds into a circuit .
I used the F1 chip so I needed to feed them by splicing wires into pickup to put headlights and tailights in my Fly Coda Lunga.

I was tring to emulate the simplicity of the Scalex boards (eg GT40).
Works a charm.
 

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Thanks guys.

I'm going to try the IN4148 diode and 1K resistors to start with for the headlight/tail lights (6 in total) wired from the guide.

Just for clarity (because I suck at this but do have Visio
) I am interpreting the headlights/taillights circuit like this:



Thanks for the help so far guys - wish I'd learnt more electronics and less computing
 

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Discussion Starter · #45 ·
Looks fine. This will take approx 80mA through the diode so would not want to put any more Led's than this through a single one.

If want to use the Brake lights at some point I would suggest using BK & HL as in my description as you can then use a common ground for them & save on wiring.

Like the output from the cct diag program, much nicer than the free one I have. Is it free or paid for?

Richard
 

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Hey Rich, is there any reason why you cant use just 1 resistor for multiple leds? if they are in parallel anyway, couldnt you replace all 6 x 1k resistors with just 1? or would there be too much current draw through it?
 

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Thanks for the confirmation.

I'm guessing that splitting the circuit and adding a further diode into another branch would keep the current drawn down.

I will do the HL/BK circuit for the brakes as suggested.

The diagram was done in MS Visio 2002, which has a full set of electrical engineering stencils (drawing elements) - not sure how much it costs these days as its part of my toolkit as an IT Consultant and I use it mostly for network and IT topology design diagrams.

Chris
 

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Discussion Starter · #48 ·
Hi

Yes one resistor feeding Led's of the same type would almost certainly be fine. I would not recomend it for Led's of different types because the volt drops across the Led's will be different and some diodes may not illuminate.

That is the reason for separate resistors even with the same Led's, however manufacturing tolerances these days are such that it usually works fine.

The other solution is what I did at the rear of the GT40, to put the Led's in series. You just then reduce the value of the resistor to get the brightness right. This can simplify the wiring as a single wire loops through the Led's.
 

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Quick update whilst I'm browsing:

I took hiredassasin's advice and wired a single resistor in parallel, one for the front and one for the rear light circuits and put a diode on each as well, so in effect there's two seperate circuits for the front and rear light clusters.

Works a treat and the results can be seen here:

http://www.slotforum.com/forums/index.php?...ndpost&p=116163

I'm currently detailing the interior whilst waiting for a batch of SSD saloon chips that are on back-order. Once I get those I can start work on the brake lights.

BTW if anyone has chipped a Slot-it HRS chassis (Sidewinder mount) I'd like to see where is best to locate the SSD LED.
 

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Here's some food for thought, if you've run out things to explore on the SSD chips.

I've just bought a Saloon conversion chip - Rev E. They've changed the PCB quite a lot from the Rev C that came in my first set.
The Rev C board has 7 distinct contact points for extra wires - all in a neat line at the bottom.
3 are common ground connections, and four have "151" resistors in series.
2 of the active connections are for the headlight and brake light connections, but which 2 are they, and what are the other two:question:

The rev E board only has 6 obvious connections. again 3 grounds
The 7th contact is still there somewhere, as there are still 4 of the 151 resistors used on the Rev C board.
The 3 sets of connections are labelled BK - brake lights, HL - headlights and SP. What could SP be for? has anybody tried this connection?

My only thought so far is speaker. It could be naff attempt to add some car engine noises, like they did 6 years ago with "megasound" If you've never heard megasound you had a lucky escape.

I hope not, but what else could you have on a slot car?
spot lights?
sparks?
spiders? (probably not as scalectrix don't make any land-rover models)

I also noticed that the 4 wires coming from the white connection block are labelled BRGY - which nicely matches the Black Red Green Yellow wires - except they're in the wrong order. it should go YGRB.
Looks like there's a number of SSD features yet to be revealed.

Iain
 

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Discussion Starter · #51 ·
Hi Iain

I have already looked at the signals on the board. Have a look at this old post.

http://www.slotforum.com/forums/index.php?...topic=8451&hl=#

My best guess was Special Purpose.

In other words they have not yet decided what to use it for.

With a change of code, the chip could for instance, turn this signal On & Off for flashing lights on the roof of a Safety car.

Alternatively it could be defined as an input for a sensor of some sort. However as it has the same 150 ohm series resistor as the other connections I suspect it is for another LED.
 

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QUOTE (RichG @ 22 Oct 2005, 08:48)Hi Iain
I have already looked at the signals on the board. Have a look at this old post.

http://www.slotforum.com/forums/index.php?...topic=8451&hl=#

My best guess was Special Purpose.

In other words they have not yet decided what to use it for.

With a change of code, the chip could for instance, turn this signal On & Off for flashing lights on the roof of a Safety car.

Alternatively it could be defined as an input for a sensor of some sort. However as it has the same 150 ohm series resistor as the other connections I suspect it is for another LED.
<{POST_SNAPBACK}>

very helpful!
Cheers,

That's what happens, when you look at the forum once every 6 months.

Iain
 

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QUOTE (novco.web @ 25 Oct 2005, 09:32)Being a total novice, anybody recommend any wire that should be used, maybe a Maplin code?

Thanks
<{POST_SNAPBACK}>As it is only LEDs you are powering, the thinest wire you have should be fine. As an example, anything the size of the wires in a ribbon cable will be sufficient. Even super-bright LEDs only draw approx 30mA each. I am not sure of gauge numbers, so can't give you a specific size.

Regards,
Ian.
 

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Hi Richard

Bit of thread necromancy here before I power up some new wiring in my scratch built Ferrari 550:

From your wiring diagram for combined brake/rear lights I notice the current for the brake lights is essentially un modified before hitting the LED's.

In the F550 the rear lights are the outer pair and the brake lights the inner pair and so are seperated.

I have wired the rear and front lights as per our discussion a few posts back and they work great. I have interpreted your brake light diagram so that all I need is the LED's for them in series with the BK/GND connectors on the digital chip (I'm using Rev E Saloon boards.

Is that correct as I'd hate to fry the Saloon board by drawing too much current from it?

BTW - Pics of the F550 are here to help illustrate what I'm talking about: Ferrari 550 Scratch build
 

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Discussion Starter · #57 ·
Hi

My circuit for the brake lights has got an additional diode, that will drop approx 0.6V each of the Brake light Led's will drop approx 1.8V giving a total of 4.2V.

There is then a 150 ohm resistor on the board which will drop the remaining 0.8V limiting the current to approx 5mA. (I = V/R)

All the above figures are approximate, as dependant on the forward volt drop of your Led's it will all change.

The Microcontroller is good to drive 25mA. I usually reccomend keeping it to less than 20mA.

You can replace the diode with a resistor. 150 ohm would be a good starting point.

With that even if you were to short the connection to ground you would only draw 16mA which will be safe.

I would then adjust the value, for the brightness of brake light that you desire, while staying with their specification.

Sorry this is a little complicated but I always think it is better to understand what is going on rather than blindly follow instructions.
 

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I hope Rich is still following this thread 'cause I'd like to say thanks, I've added rear & brake lights to three of my GT40s now and they look fab. By the way have you done any MkIs? If so what LED did you use for the larger single lights?

Thanks again Rich and all you digital people
 
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