Sunday, February 13, 2011

Back to Soldering

I have been having fun with the FUNcube (see previous posts) and ignoring my soldering iron lately, to solve that problem I decided to complete the design of my QRSS Beacon. This project has been in the  design stage for sometime, I have been working on; Designing the Circuit, Finding Parts, Creating the Schematic, and PCB layout.

This is will be the first of two Beacons using this design:
  • The first is a prototype or proof of concept
  • The second (if all goes well) will be mounted within an insulator of a dipole, or maybe launched with a balloon.

For this design I am using a K1EL Keyer, which with be programmed with a CW KEY and then put into QRSS Beacon Mode.

As stated before, I enjoy building very small projects:

"As small as I can - to see if I can - as long as I can, . . . see"

I have created similar QRSS Beacons before, this is the first which can be programmed just before use, or used interactive via a CW Key for demonstrations.

This board measure 1.25 by 1.05 inches. The small traces are 8 mils, clearance 12 mils, the text font is 3pt, the ground grid is 8 mils on 36 mil center. I wanted the board to be only 1.0 inch wide, but just could not squeeze the last .05 inches from the width.

So far, as reported here, I have created the board using Toner Transfer, and plated it with solder wipe. Parts with be added for the next blog post.

After Lamination, All Goes Into Warm Soapy Water

Toner Transfer Paper Floats Away

Previously I have normally use a soft spoung brush method of etch, this time I am going to try something new (as seen on the web) - I going to try the "Etch in a Bag" method.

Ready for Etch

Etch in a Zip Lock Bag

With this method, it is easy to watch the progress and mix the solution

I found this method very easy and uses very little etch. I was able to heat the etch while in the bag, by running hot water over it - it etched the board very fast. Also, I noticed that it is best to NOT allow the etch near the zipper - it will creep out while zipping and un-zipping, and will make a mess.

Ready for Resist Removal, I use warm running water and Scotch Bright

Solder Wipe with lots of Rosin

Solder Wipe is done by sliding a short section of Solder Wick over the traces with the tip of the soldering iron. With very little solder on the wick, solder coats the traces, and excess is removed by the same wick in a wiping action. This is best done in the presents of plenty of rosin flux.

After clean up; with Alcohol and more Scotch Bright (to remove solder shine), and a new thin layer of Rosin for protection. If un-removed, the solder shine is very distracting while placing components.

Ready for Trim and Parts

Note: I may have rubbed too aggressively while removing the shine, as the solder wipe is now very thin.

Total time from laser print to finished board:  about 20 minutes.

Note: Unlike all previous posted photos on my blog, for this post I used my HTC Droid Cell Phone Camera. It looks like I could use a Macro Adapter for the phone - I will look into its availability.


No comments:

Post a Comment