lighting a d'deridex warbird

paradoxum · Post by **paradoxum** » Sat Jan 29, 2011 3:45 am

going to be starting this project soon; http://www.starshipmodeler.com/trek/jk_ddrex.htm

and i'm at the stage of planning the electronics and purchasing stuff.
my previous model went straight into the mains with an old 5v phone charger with no switch or anything, and I hooked the plug directly into the internal wiring, but I want to do this one properly and just want to run things by you guys first.

if I use high powered LEDs do I still need to use resistors with a 5v power supply? I was playing with this http://ledcalculator.net/ and it seems I might have to, but I didn't bother with my previous kit and the leds are still going strong after a year+ of being constantly lit?

Anyway, this is the stuff I was planning on getting could you tell me if it looks ok?

In my previous kit I just twisted the wires around the led legs cause I didn't have a soldering iron, but as I want to do this properly i'll have to pick one up, nothing fancy or expensive, will this do? http://cgi.ebay.co.uk/270573240104
Power supply - http://cgi.ebay.co.uk/290520297772
5.5mm DC female jack connector - http://image.made-in-china.com/2f0j00UB ... C-Jack.jpg (this would go into the base somehow, haven't figured out the base yet though.
For an on/off switch I was thinking of something like this; http://cgi.ebay.co.uk/270581937574 which I would have at the back of the mount.
for the enclosure I just found these boxes which look like they might do nicely; http://www.maplin.co.uk/mb-plastic-boxes-1676 so i'd need to drill out holes for everything in there which shouldn't be a problem, also could weigh them down with something too.
Green LEDs for nacelles; http://www.maplin.co.uk/5mm-superbright ... -led-45938
as for the window leds, i'm not sure if I should use white leds or yellow ones for a more warm glow, any ideas?

any help/tips/suggestions would be greatly appreciated.

Sparky · Post by **Sparky** » Sat Jan 29, 2011 1:39 pm

those green leds say max voltage of 3.6 volts. 5 Volts will be bad for them, if you connect them in series so they want 6.4 volts 5 volts will probably power them up and they will last for many years (+led-+led -).

You will need to test the power supply, some of them are not well regulated.

plug it in turn it on with out hooking it up to anything, and measure its output voltage, as long as it is not more the 6.4 volts you won't need the resistors. don't eye ball it you need a meter, over driving the LED will eat into it run time life.

You can find the DC jacks that are panel mount (threaded body with a nut) that will allow it to hold the weight of the ship. Consider using the 1/4" mono or stero jack it can hold more weight. Even if you use a smaller rod to mount the ship, the jack needs to hold the wieght and withstand the lever action of the ship on the end of the rod.

paradoxum · Post by **paradoxum** » Sat Jan 29, 2011 1:45 pm

Sparky wrote: You can find the DC jacks that are panel mount (threaded body with a nut) that will allow it to hold the weight of the ship. Consider using the 1/4" mono or stero jack it can hold more weight. Even if you use a smaller rod to mount the ship, the jack needs to hold the wieght and withstand the lever action of the ship on the end of the rod.

thanks for the reply!
i'm having trouble finding a suitable rod and the connectors to hook it up to the ship/base like you mention though, i've searched for threaded rods, threaded tubing, etc, I can't find anything that will work! where do you guys get your stuff from ?

Sparky · Post by **Sparky** » Sat Jan 29, 2011 1:55 pm

If you use brass rod, you can get that to solder to the strain relief in the 1/4" jacks. You must be careful, the brass rod will want to get very hot to let the solder flow, but that much heat will start to melt cheaper jacks.

you help avoid this:
1)clean the brass rod with fine grit sand paper at the end where you will solder the connector on (also needed at the end where the putty will grip it in the model)
2)pre tin/solder the connector's strain relief with acid free flux and standard solder
3)Pre-tin/solder the brass rod after it has been cleaned using acid free flux and regular solder. while the rod is still hot from the tinning solder do the solder to the connector's strain relief.

Also forgot to mention, you should get tip tinner for your soldering iron, even a cheep iron can be used if the tip is kept clean and the tip tinned. Cheaper soldering irons don't come tinned, they will not solder with out a tinned tip.

Sparky · Post by **Sparky** » Sat Jan 29, 2011 1:58 pm

note the 'tinning' of a part prior to soldering is not the same thing as tip Tinner. they share the name. I can find a pic of a little dish of tip tinner.

paradoxum · Post by **paradoxum** » Sat Jan 29, 2011 2:06 pm

sorry you've completely lost me now, I don't even know what you are talking about

Sparky · Post by **Sparky** » Mon Jan 31, 2011 1:45 pm

The solder iron you linked too has to be prepared to be used as a soldering iron, this procedure is simple but requires a specific product:
1) let the iron heat up to normal operating temperature
2) plunge the tip into tip tinner for a moment (regular solder will not do the trick)
3) iron is now ready for general purpose soldering.

On the topic of using a brass rod as a mount:
You can solder a brass rod into a male jack.

Male jacks usually have a solder-able metal strip with tabs meant to clamp down on the cable which it is to be attached too, this is to make the physical connection from cable end to the connector, an electrical connection is made by soldering wires to the connector where needed, solder joints are not meant to carry weight or resist pulling forces, the strain relief must take the physical stress.

To get brass rod ready to solder to you should get a good layer of solder on one end first, and do the same to the connector's strain relief.

The amount of heat needed to get solder to flow to a big piece of brass is large, the amount needed to get solder to flow to the connector's strain relief is small, the connectors innards will start to melt if you are trying to heat the rod and get solder to flow while they are clamped together.

If this still doesn't make sense my best advice is to get a few jacks and so that you have enough jacks on hand to get the technique perfected at one sitting.

A picture is worth a thousand words of course. But I don't have one posted, I have used this technique on a very small model. I'll see if I can get a picture of the model tonight.
http://www.starshipmodeler.info/wfest2k4/pa_j_552.JPG