The end connector pins have been crimped and soldered. (Click to enlarge)	The pins are inserted into an end connector housing. (Click to enlarge)	The cable is now ready to be used. (Click to enlarge)

This tutorial will teach you how to build your own end connector cables, which can connect directly to the RAMB or other microcontroller motherboard. While you can buy cables with end connectors already installed (for example, BP Hobbies sells a prefabricated 3-conductor cable with Futaba-type ends), there are times when you have to make your own ends. The wires of our connector cable could come from a sensor, servomotor, voltage divider, or whatever, and will plug into our microcontroller's motherboard.

Read my book to learn the how's and why's of connecting and programming such external devices as: LEDs (Chapter 3) servomotors (Chapters 11-13) infrared range finders (Chapter 16) voltage dividers (Chapter 17) piezo buzzers and audio transducers (Appendix D) grippers (Appendix G) and and turret mounts (Appendix G)

Before we make our own cables, you'll need to learn how to solder connector pins to bare wires. If you don't know how to do this, see my tutorial to learn how.

The cable we'll make in this tutorial is a designed to plug into the signal, power, and ground pins of any microcontroller motherboard whose header pins are seperated by 0.10". My motherboard of choice is Robodyssey's RAMB or RAMB II. (RAMB stands for Robodyssey Advanced MotherBoard). You could make your own motherboard from scratch, but why bother when Robodyssey has made a beautiful, robust, and innexpensive motherboard that guarantees that your BX-24 applications will run flawlessly.

Read Chapter 11 in my book to learn the in's and out's of the RAMB's power, signal, and ground pin configurations. Pay close attention to the sections that cover regulated and unregulated power!

Making end connectors require just a little knowledge, a few pieces of equipment, and a few tools. Read on...

I'd sure like to hear from you. If you find my tutorial helpful or if you would like to leave a comment, please send me an email.

Table of Contents for this Page

1. Gather Your Materials
2. Solder the End Connector Pins to Bare Wire
3. Insert the Connector Pins Into the Housing
4. Plug the Connector Into the RAMB and You're Ready to Play

Gather Your Materials

To make our connector cable, you'll need the following supplies and tools: Of course, you'll need wires to which the end connectors will be attached. Either collect three individual wires or one 3-conductor cable. Preferably, each wire should be a different color. In this tutorial, I use a white-red-black combination, as shown in Figure 1. These colors correspond to signal-power-ground in the usual way.   You should follow the convention of light-to-dark as described in my book on page 176. (That is, the lightest wire is the signal wire, the darkest is ground, and the middle wire is power.) The wire can either be solid or stranded. In this tutorial, I use solid 22 AWG (American Wire Guage)wire but stranded wire will work just as well. In fact, I try to use stranded wire as often as possible since it won't break like solid wire does when it's bent a number of times. We need the usual soldering and crimping tools pictured in Figure 2. These include a wire stripper, needle-nose pliers, pin crimper tool, solder, soldering iron, and soldering iron tip cleaner. (See my tutorial on soldering end pins for more details about using these tools.) End connector pins, shown in Figure 3. I like using pins from Jameco (P/N 100765). These gold pins are suitable for wire whose guage is between 26 & 22 and can carry a current of 1A. For this project, we'll need at least three end connector pins. One end connector housing (see Figure 4). (Jameco P/N 157382.) This plastic housing provides a pin separation of 0.100" -- perfect for the RAMB and many other devices. (Optional) Small screwdriver. (Really, anything with a small tip will do, such as a pen, tip of a key, even a fingernail.) (See my list of tools and supplies for prices, part numbers, and other useful components.)

Click on the images below to enlarge them. Figure 1. Our cable will be made with three wires of different colors. Figure 2. Some tools needed for the job. Figure 3. End connector pins will be crimped and soldered to bare wires. Figure 4. The housing for the end connector pins.

[Return to the top.]

Solder the End Connector Pins to Bare Wire

This step looks short but it's not. We now need to strip the ends of our wires and solder the end connector pins to the bare ends. If you haven't ever done this, it could take a little while to get the hang of. If you don't know how to do this see my tutorial on soldering end pins to bare wires. Your wires should now look like the ones in Figure 5.

Click on the images below to enlarge them. Figure 5. End connector pins have been crimped and soldered to bare wires.

[Return to the top.]

Insert the Connector Pins into the Housing

All we have to do now is insert the connector pins into the plastic housing. Actually, this step can be troublesome if you insert the pins backwards -- which is not difficult to do -- so pay attention! At the completion of the following steps, you'll have a cable equipped with an end connector that can be plugged into the RAMB or other motherboard. Align the three wires as shown in Figure 6. Be sure that the connector ends are in the same orientation. If one pin is twisted sideways, gently untwist the offending wire (do not twist the connector) until all pins have the same orientation. Gently guide the end connector pins into the plastic housing. You can insert them all at once (as is shown in Figure 7), or you can insert them one at a time. Either way, make sure that the signal pin is inserted into the proper slot. Most connector housings have an indicator to mark the position of the signal pin. My housing uses a small triangle to denote the signal pin, which is shown inside the yellow circle in Figure 8. Also, ensure that the wires follow the light-to-dark convention. Notice that the wires follow the white-red-black pattern. At times, a stubborn pin will not slide easily into the housing. This is often caused by some protruding piece of solder or by a tab that was improperly crimped. If this occurs, remove the pin and try to fix the problem with a solder iron, crimp tool, or pliers. If the pin still won't slide in easily, you may need to use the head of a small screwdriver to push the pin into the housing. Be careful not to damage any wires when doing this. You will know that the pins are fully inserted when you hear an audible click, indicating that they have slid past the safety stop. (The safety stop prevents the pins from being pulled out of the housing.) When fully inserted, the pins will resemble those in Figure 9. If the pins seem loose or feel as if they may slide out of the housing, you should depress the plastic safety stop tabs down with a small screwdriver or similar device as shown in Figure 10.

Click on the images below to enlarge them. Figure 6. All three wires should have the connector pins in the same orientation. If one pin is twisted sideways, gently untwist the offending wire (do not twist the connector pin) until all pins have the same orientation. Figure 7. Here, the end connectors are inserted all at once. Of course, you can insert them one at a time, too. Figure 8. Make sure that the signal pin is inserted into the proper slot. This particular housing uses a small triangle to denote the signal pin. Also note that the wires are in the proper order, from light to dark. Figure 9. The pins are fully inserted into the housing. Figure 10. If the pins seem loose, you may need to push the plastic tabs down with a small screwdriver or similar device.

[Return to the top.]

Plug the Connector Into the RAMB and You're Ready to Play

The cable can now be used for your BasicX projects. Figure 11 shows my cable properly connected to the pin 8 on the RAMB (BX-24 pin 13). Notice that the white signal pin is properly positioned adjacent to the BX-24 microcontroller and the black ground pin is positioned farthest away from the BX-24. We don't need a cable to make use of the a housing connector. Figure 12 shows an external LED assembly that is plugged directly into a housing connector. (See my tutorial on making these handy little guys.) Using them is a snap: simply connect one to the RAMB (see Figure 13) and you're ready to create a light show, show off your Morse Code skills, or signal for help.   Read my book to learn the how's and why's of connecting and programming such external devices as: LEDs (Chapter 3) servomotors (Chapters 11-13) infrared range finders (Chapter 16) voltage dividers (Chapter 17) piezo buzzers and audio transducers (Appendix D) grippers (Appendix G) and and turret mounts (Appendix G)

Click on the images below to enlarge them. Figure 11. The cable is properly connected to pin 13 on the RAMB (BX-24 pin 8). Note that the signal pin is adjacent to the BX-24. Figure 12. The cable is properly connected to pin 13 on the RAMB (BX-24 pin 8). Note that the signal pin is adjacent to the BX-24. Figure 13. The cable is properly connected to pin 13 on the RAMB (BX-24 pin 8). Note that the signal pin is adjacent to the BX-24.

[Return to the top.]

I'd sure like to hear from you. If you find my tutorial helpful or if you would like to leave a comment, please send me an email.