Back in November of 2011 I did a post on Micro Connectors, this post is an update. It took me a long time to locate my first source for the ultra small connectors.
Since then I have found several sources for the 40 pin header strips. It is rather easy when you know what your looking for. Header Strip is the key word to use in a search machine. There are two basic versions that I commonly use on my model railroad, Single and Dual row strip headers with 0.10" spacing.
A typical E-Bay Search would be "Dual Row 2x40Pin 0.1"/2.54mm" & "Single Row 40Pin 0.1"/2.54mm" Header Strip.
The header strips have detents for cutting between pins. The header strips can be cut to any amount of conductors needed for making custom connectors. Their super small size makes them perfect for model railroading. The dual strip is the exact size for the common 8 pin NMRA DCC connector, a dual 40 pin header will make 10 DCC connectors for less than $2. I use my Atlas Fine tooth rail cutting saw for cutting the headers in my Panavice. The pictures below show the header strips and are self explanatory.
By using K&S .02" Brass Rod as connector pins it is easy to make the connectors polarized to guarantee proper conductor lineup preventing the plugs from being inserted in reverse as shown in the picture below.
By cutting ¼" lengths of the .02" rod and soldering them in the female side of the strip you can develop several combinations to prevent the wrong connectors being used together.
The Micro Connectors can be used almost anywhere on the layout. By installing a female connector flush mounted in a road and a male connector under a vehicle with lights you have easily removable cars and trucks. By using a female connector under the vehicle and .02" removable rods the vehicles can also be placed where there isn't a connector in the road with the rods removed.
Before I found a source for the header strips I used K&S 1/16" brass tubing in the roadway with ¼" spacing as the female connector and K&S brass .03" rod as the male connector on the bottom of my vehicles.
The Mailster has a 1½ volt 1 mm lamp installed in the headlight and the connectors are .03" brass rods that plug into 1/16" brass tubing buried in the road.
I have installed the 8 pin Header type NMRA DCC Micro Connectors between all of my steam locomotives and their tenders. Every locomotive and tender is wired for a DCC decoder decoder with a 8 pin female connector. If the locomotive isn't using a decoder I use dummy plugs also made from the header strips inserted into the decoder connector so that the engine will run on a regular DC power pack.