DIY Navigation lights and Servo Speed control

 I thought I would  give the trees a break from smacking my planes so I decided to write an article on some thing different this time.

I have been searching the internet for serveral months now trying to find ways of controlling Servo speeds and making my own light system . After several attempts and many failures I finally came up with what I think is a decent system ( Good enough for me anyway). Please believe me I am not an electrician or electronic wizard but there is enough information on the internet now to be dangerous .I do have a basic understanding though . If you feel uncomfortable doing this than don't. You still need to be careful you can cause parts to over heat and blow up but in general it just wont work if done wrong.

The following is a an explanation of what I have done and how I did it. Schematics for the circuits are also included in PDF format .

For the light system

I first started with a bread board and a 555 timer chip some resistors ,capacitors and  LED's. EventuallyI went with a 556 timer and a 4017 ic for the main control and it worked the way I wanted it to. Below is the bread board all wired up.

Now this obviously will not fit in an airplane made of dollar tree foam so I transferred it to a perforated board I bought from an electronics store. The video below shows the end result I used on my DTF beachcraft Design

That wasn't enough I wanted to make a nice package almost like I bought it from a store . I searched and studied many web pages and learned how to make a PCB ( Printed Circuit Board)

First off you need to copy what you made on the bread board to a schematic.There are many programs available for free but I did it on a cad program I have.You could even do it on a piece of paper by hand as this is just fo reference.  Once I had the schematic printed out I could see where everything needed to go. I then proceeded to draw up a pcb design on Cad again. After completing the drawing I printed it out using a LASER printer on overhead projector sheets (clear). It must be a Laser printer. Inkjets will not work for the process I am doing .The process I am doing is called Photoresist and has two stages. Stage one is   more or less take an exposure of the drawing on top of a special treated copper board called presensitized copper clad board.

Then develop the picture in a solution . After that it is soaked again to remove the copper not protected by the schematic

 I cut out the schematic and taped it to a piece of glass and also cut a piece of copper clad to fit . I turned off all the lights and turned on a red Light to make it a dark room of some sort ( I actually used a red candy cane decoration that I hadn't put away yet). I pulled off the protective coating on the board and laid it on the table .Then placed the schematic on top of the board, Placed a small table lamp over the glass and turned it on. Leaving  it sitting  for 15 minutes exposure. While this was occurring I prepared the first bath which is a developer solution. Please make sure you are wearing protective glasses and gloves while working with chemicals

After 10 to 15 minutes under the light I put it in the solution to develop it

 10 minutes later after occasionally stirring the solution and moving the board around the picture starts to show. I learnt through trial and error that you must be patient and make sure all the protective coating has dissolved  away leaving only a copper looking part with the schematic.

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After  it looks like the above picture it is to be removed and flushed with cold water to stop the reaction of the developer. It is now ready for the next step. which is to dissolve the copper all around the schematic using a chemical called Ferric  Chloride. All of these chemicals and boards can be found at an electronics store like Radio Shack in the US or Sayal in the Toronto  Canada area.

Ferric Chloride is nasty stuff , not that it burns but that it stains everything it touches. I highly recommend gloves and old clothes and protect your work area . This stuff just stains everything .

Now place the board in enough ferric chloride to completely cover it. The manufacturer recommend that it is heated  slightly but not necessary. The heat just speeds up the process a little .Agitation  is also needed. What I do is wait for laundry day and place my bowl with the board on top of the drier, This keeps the fluid warm and the movement acts as an agitator  somewhat. On occasion I will go and check it and give it a shake. Not everyone has a drier so it will still work just keep shaking it every once in a while .This process usually takes half an hour until all the copper has been removed except where the lines from the schematic are. Note if you leave it in too long it will eventually eat the lines away also.

After half an hour or so it will look like this  below . No it didn't shrink ( lol)    it's just a different board for the picture

Drill out all the areas  where indicated for parts to be mounted .

Refer back to the schematic and assemble the board.

Here is a picture of the servo speed control board completed it weighs 9 grams

 Navigation lights video on breadboard before making schematics

 Demonstration of Servo speed control video

The servo speed control is the same process but a different chip configuation .The chip I used was a

Picaxe 08m2. that I programmed . I can not take any credit for the actual program written I found it on the internet (Kevin Goom 2005) I purchased the chip and programmer on line for under $10.00 CND from ROBOT SHOP.  http://www.robotshop.com/ca/  

If you have any questions do not hesitate to comment  I will try to answer your questions  Just remember I am no way an expert in this I may have just fluked out.

The light schmatic is when I used two 555 timers. the 556 is the same thing just putting  two 555 timers in one chip

lights pdf    using two 555 timers  and a 4017 ic ( 25 grams)

Servo speed control pdf      (9 grams )

Happy Flying     or tree embracing  as I do a lot of

And for my next project coming soon