August 1998

In my junk box were several broken computer mice.  I thought they must be good for something. It struck me that a small QRP transmitter would fit nicely inside them.  I build  30 and 40 meter transmitters a couple of years ago and had wanted one for 20 meters. I got out the QRP CLASSICS and on page 10 found the "Little Joe" transmitter plans.

First, I listed the parts needed and began to hunt up a source for them. Often it easier and cheaper to go and buy someone's kit  because all of the parts are in one place.   Well, I usually do it the hard way, from scratch. I etch my own board and find my own parts.
Instead of a weekend project it turns into months and years.  I find you cannot get the all parts from one source. I bought a crystal from Jan. They have minimum order plus shipping charge.  So I ordered two crystals and two sockets for them which came to $26.  All crystals are made to order.  Shipping was in six weeks.  It was the same with the
other suppliers.  Minimum orders plus six to ten dollar handling charges. This is for parts that fit inside a small envelope.   I had to double the parts ordered for spares and add a couple of wire strippers to make the order.
Another order was  for just a two-dollar transistor and another one for a fifteen-cent inductor.   Total parts in the mouse are worth no more than fifteen dollars. But with spares, multiple suppliers,  handling charges,
postage  and other I spent  more than one hundred dollars  not including gas and phone calls.  However, I have the pleasure of saying "From scratch I built it."  Do not believe the experts that say you can build them from your junk box and old TVs.  The right parts numbers are never found
there.

All parts finally arrived and the fun began.   I got out the etching kit
which I purchased from Radio Shake for $19 when I built the others.  To make the board fit inside the mouse, I reduced the pattern some.  Also I trimmed some excess plastic out of the mouse and retained the original micro switches for the key.  Two holes were drilled and plugs mounted in the back of the mouse for the antenna and power. Then I traced the reduced pattern on the copper board and etched the board.  With my drill press ($49) I drilled the holes for the components.  A small drill bit was two dollars. Before installing components, the circuit board was cleaned and shined with steel wool ($2).
 
The tracing was checked again and then I began installing the largest
components first. Before I began soldering, I waited until most of the
items are on the board. Then I checked them again to be sure
they are in right places.  Lastly, I wound the Torrids with the enamel wire.  The enamel coating was stripped off the ends so that the solder would  adhere properly.  I soldered  every join carefully being sure not to overheat the joint or component, however using enough heat that the solder flowed and would not make a "cold solder joint."  After the solder begins to flow, I count to four with the iron on the joint and then pull it off quickly.

Carefully, I Examine the soldered board with magnifying glass for
"bridging" where it should not be. And I am ready for the truth test.  Did you do it right?

The dummy load is then hooked to the antenna plug.  Tune the receiver  to the proper frequency.  Then hook up the power to the mouse.   Push the mouse button and you may hear an oscillation on the receiver.  Tune the receiver to center of frequency. Mine was a little lower than the crystal frequency.  If you are using a power meter, you can tune the transmitter for maximum output.

However, On the truth test,  my mouse had little oscillation.  I thought maybe the crystal is not good, so replaced that.  No change.  I laid it aside for a month.

Maybe the variable capacitor is not big enough. So I changed that.   No Change. I laid it aside for two months.

January 1999 After about five months of labor on the thing, I thought Maybe the torrid was wound wrong. So because I had extra ones.  I wound new one tighter and with the secondary on the opposite side instead of overlapping the primary.

Victory. It works . . . it works with better than two watts.   Now to work  Dave in Antarctica!

Next I need to build a matching receiver into another mouse, from
"scratch" of course. Its mighty disappointing when you build something and it does not work.  But the best thing to do is to lay it aside for a while and come back to it later.   When you finally get it working, and you will, you will be so excited you will be ready to take on another project.

Now my wife just got a new cat which likes mice and he scratches a lot. That gives me another idea. Scratch Power! . . .  Maybe a mouse with a cat antenna.  Hmm, I will think on that a while.   I will use a woofer to send Scratch up a tree with a wire.   Must be the RF getting to me?