andy watson Posted May 26, 2009 Share Posted May 26, 2009 I have found a number of navigation light rigs that (as far as I can tell) run a combination of flashing and solid lights of assorted colours around a wiring system that runs all over the plane. These are obviously replicating the real thing, and cost about £20. I am hoping to save a little cash here, as on my stuka I need a single landing light which can be controlled by an on/off swith on the tx. Unfortunately I haven't seen such a simple system for sale- could I make one (bearing in mind I am completely ignorant of electronics!). If I did make one, would it save me any money? Quote Link to comment Share on other sites More sharing options...
Olly P Posted May 26, 2009 Share Posted May 26, 2009 Andy, It would be a relativly easy thing to design and make, the question would be if you have a spare chanel on your TX/RX set up that could be configured correctly for the design i.e. directly powering the light from the Rx, or using it to activate a switch and then a subcircuit. which system would depend mostl on weight and power limitations. I can try to find 5 minutes to design one if you want. Olly Quote Link to comment Share on other sites More sharing options...
Roger in Dubai Posted May 26, 2009 Share Posted May 26, 2009 Hi Andy I bought a set of lights for a Top Flite Cessna 182 Skylane I am building and bought them from Ross Mansell who advertises in the "other mag" (sorry David) under the name of "Lighting for Aeromodellers". He also has a website www.lightingforaeromodellers.co.uk on which you can see all the stuff he has to offer. Please note that I am in no way connected to Ross and just a satisfied customer. Like you, bit of a novice with all this electronic stuff and this system is foolproof, and works. Just thought the Skylane would look great with strobes and landing lights. Good luck with whatever you choose. Quote Link to comment Share on other sites More sharing options...
birdy Posted May 26, 2009 Share Posted May 26, 2009 I think brc hobbies do the type of thing you are looking for. Quote Link to comment Share on other sites More sharing options...
andy watson Posted May 26, 2009 Author Share Posted May 26, 2009 BRC do the full rigs at £20. I will buy theres if I have to, but it seems a bit silly spending that much to either cut off the un needed lights, or to stick a cable tie around them and bundle them away in the wings! Thanks for the lighting link. They seem to be the kind of thing I am looking for, but he does seem very secretive! Whats all this posting stamps about? I did think I might be able to find an LED from Maplins, cut one end of a servo extension lead off, and fit the LED onto the end. Of course, this is probably far too simple! Quote Link to comment Share on other sites More sharing options...
Olly P Posted May 26, 2009 Share Posted May 26, 2009 Yes, but what voltage are your servos? Ensure that the LED voltage is correct! PM Sending shortly Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 26, 2009 Share Posted May 26, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
andy watson Posted May 26, 2009 Author Share Posted May 26, 2009 well the battery could be either 6V or 11.1V with whats going in the plane at the moment. Obviously I will need to pick an LED that would match whatever voltage I use. I kind of thought if the switch was off, there would be 0V. If the switch was on, it would get full power! Returned the PM newbie/oldie. Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 26, 2009 Share Posted May 26, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
andy watson Posted May 26, 2009 Author Share Posted May 26, 2009 That helps a lot Phil...................I will leave it to the professionals.......! Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 26, 2009 Share Posted May 26, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted May 27, 2009 Share Posted May 27, 2009 It's actually quite easy. You can use the circuit board from any old servo as a switch. Just wind the pot to one end and use the motor drive connections to power an LED with a suitable current limiting resistor in series. The servo circuit will see the operating arm of the servo as being at one end of its travel and continuously drive the motor to try to send it to the other end if you program a switch function (like retracts for example) on that channel. Putting the pot at the other end of its travel will reverse the function (and polarity of the motor connections). The pulse width mentioned is a bit of a red herring. While the servo feedback pot thinks the arm needs moving to the other end of it's travel it will be feeding full power to what it thinks is the motor. I've used this system for a few years on my Chipmunk with no problems. It would be safer to use a separate battery to power the servo board/LED as per retracts but the drain is only a few milliamps - typically 20 -30 mA per LED. Edited By Martin Harris on 27/05/2009 01:20:51 Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 27, 2009 Share Posted May 27, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
andy watson Posted May 27, 2009 Author Share Posted May 27, 2009 So, If I put aside my ignorance of how to actually do it, I can rig up a switchable landing light for the price of an LED, an old servo and a servo extension lead. Unfortunately most of Martins post looks like it is written in Swahili to me! Newbie/Oldie has very kindly offered to try put something together for me, so maybe I won't need to learn what it all means! A 20/30 mA drain doesn't sound like enough to make a difference to a receiver battery............. does it? Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted May 27, 2009 Share Posted May 27, 2009 You'd need a resistor in series with the LED as well - the exact value will depend on the battery voltage and the LED used. So in my best pidgeon English, open up an old servo, discard all the gears, find the little electric motor, disconnect and discard it, wind the potentiometer all the way to one end of its travel*, connect the LED and a resistor via sufficient wire to locate the light where you want it, in series to the old motor connections and Bob's your Mother's brother. There are on line calculators e.g. that will simplify the task e.g. http://led.linear1.org/1led.wiz and you'll need to obtain the required info for your chosen LED from your supplier e.g. http://www.maplin.co.uk/Module.aspx?ModuleNo=45936 I've used a nominal 5v for a charged 4 cell pack in this example, a forward voltage of 3.2V to be at the safe end of the range quoted and the forward current quoted of 30mA which gives a recommendation of 68 Ohms. Have a play and you'll soon see how easy it is. The only real danger would be a wiring fault draining the battery but the most likely failure mode would be an open circuit so there's not an undue risk using the receiver battery (in my very amateur opinion). *Polarity is important and it would be easiest to find a clubmate who can use a voltmeter to show you which way round to connect the LED. Quote Link to comment Share on other sites More sharing options...
andy watson Posted May 28, 2009 Author Share Posted May 28, 2009 Well except for the word potentiometer I actually think I understood all that! From the looking around I have done it looks like it is possible to short cut the whole resistor issue and buy an led set up with a resistor designed to run on 12V. From the point of view of an electrical incompetent such as myself, that approach seems sensible- especially as I plan to have an 11.1V 3s LiPo in the plane to power the siren. So, in my head I have a diagram of an old servo connected to the receiver, and the LED soldered into the servo at the point where the motor was. That seems sensible, but how do I get 12(ish)V to the LED without frying my receiver? Quote Link to comment Share on other sites More sharing options...
Olly P Posted May 28, 2009 Share Posted May 28, 2009 Andy, Have now sketched a design which will allow you to do this, without destroying on old servo! I'll pop to maplin tomorrow on my way home and pick up the extra bits i need and get it built over the next week or so.... Olly Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 28, 2009 Share Posted May 28, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Olly P Posted May 28, 2009 Share Posted May 28, 2009 Polyelectrician, you say the Vs to the servo is 5V? Andy, What color light do you need? Edited By Newbie/oldie on 28/05/2009 10:55:29 Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 28, 2009 Share Posted May 28, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Olly P Posted May 28, 2009 Share Posted May 28, 2009 I'm planning on something quite simple to make this work from the 11.1V Li-Po which is also being used for the siren. This means the main flight pack will purely supply a 'switching' signal to a relay to engage the landing light - thus if a low power landing is being made then the landing light won't cause a lack of power. I'll draw up the diagram electronically when I get a minute Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 28, 2009 Share Posted May 28, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Olly P Posted May 28, 2009 Share Posted May 28, 2009 Interesting. Dependant upon colour desired they are arong 20-40p at maplin. Right, paint for drawing circuits-Visio is on my PC at home but not the one here! Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 28, 2009 Share Posted May 28, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Olly P Posted May 28, 2009 Share Posted May 28, 2009 Phil, do you mean in series or in parrallel. I have sketched up a quick diagram without those diodes, but can drop them in easily. Quote Link to comment Share on other sites More sharing options...
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