Terminal Strip - Homebrew Style
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- updated December 24, 2015 -
Below I show you how to create your own homebrew terminal strips using common 0.100" spaced perforated breadboard and #20 AWG (0.032" / 0.812mm) copper wire.
Strips containing any number of terminals can be created. Note the relationship between the number of holes left intact in the perf board and the number of terminals. The upper copper loops form the actual terminals, and the coper anchor wires on the bottom allow soldering the strip to the ground-plane of your Manhattan or other construction method boards. All terminals are insulated from each other and from the anchor wires.
The finished product ready for instillation.
Lets get started...
We start with a piece of perforated breadboard and a method of cutting it. Here I show tin snips, but you can use whatever method your prefer.
CAUTION: When cutting fibreglass board, use the proper personal protection equipment. Fibreglass fragments can be harmful to skin and eyes when handled, and is very harmful to lungs if inhaled when saws or other powered cutting equipment is used.
Start by cutting a section of board in such a way which leaves two rows of holes intact running horizontally. The width of the board should contain a sufficient number of intact holes to accommodate the number of terminals you need. The formula used for single hole spacing is [(# of terminals x 3) - 1]; e.g. for a four terminal strip, this works out to be [(4 x 3) - 1 = 11]. You can, of course, use more rows of holes to add height, and more holes between terminals if you require greater spacing between terminals.
Cut a 1-1/2" (38mm) length of #20 AWG (0.032" / 0.182mm dia.) copper wire for each terminal you need, plus four more for the anchor wire assemblies. I find it helpful to clean the wire with a fine grade of steel-wool before cutting to promote easer soldering; however, use the steel wool far away from your bench to avoid getting the dreaded "Murphy's whiskers"* syndrome.
*"Murphy's whiskers" - A term coined by Bill N2CQR of SolderSmoke blog and pod-cast fame describing small strands of wire that shed from the shield braid of RG-174/U and other coax cable (and steel wool fibers) that can cause intermittent shorts between components in your circuits.
Using 5/64" (2mm) chain nose pliers (or other tool), grasp the wire in the center...
...and bend the wire exactly in half.
Grasp the loop end of the wire assembly in such a way as to provide a bending edge approximately 1/4" (6.35mm) down from the top of the loop. Here I use the width of my pliers as a convenient gauge.
Bend the wire loop ends to form a 90 degree angle.
Insert the loop assembly into the first two holes of the perf board...
...and bend the legs up, over the edge, then down the other side of the board...
...like so.
Cut off the excess ends of the legs. Here I'm using the Hakko CHP-170 Micro Soft Wire Cutters (Currently $4.37 at Amazon, Home Depot and other stores).
Clench / crimp the bent legs tight to the board using broad nose pliers to add stability to the terminal.
When done, your terminal should look something like this.
Repeat for each of the remaining terminals leaving one open hole between each terminal loop.
The solder side.
Solder each terminal.
CAUTION: Wear safety glasses! DO NOT inhale the solder smoke. Use a fume extractor or fan to draw the fumes away from you.
When done, your terminal strip should look something like this.
We now add the wire anchors to allow the terminal strip to be soldered to the board.
Position the terminal strip so the solder side is away from you. Insert one anchor wire assembly directly under the first terminal with the loop end toward you. Bend the right leg down, then under the strip, and then back toward you. Bend the left leg so it points to the other end of the strip and is on the solder side of the board.
Now turn the board over so the solder side is toward you. Insert another anchor wire assembly in the next two holes with the loop end toward you. Bend the right leg down, then under the strip, and then back toward you. Bend the left leg so it points to the left edge of the strip and is on the non-solder side of the board. One each side of the board, position the leg that points to the edge of the board so that it's positioned directly under the loop portion of the other anchor wire assembly, then trim it with your cutters.
On both sides of the board, solder the leg of one anchor wire assembly that points to the edge of the strip, to the loop portion of the other anchor wire assembly.
Repeat the steps above for the other anchor wire assemblies, but make it a mirror image of the other.
Notice how the anchor wire assemblies now form a stable fixed anchor point, with two legs in one direction, and two legs in the other. This may seem like a lot of work, but it keeps the terminal strip from tilting over; i.e. pivoting within the anchor assemblies, as it would do if only a single loop of wire on each end were to be used.
The finished product.
View from the bottom.