Making Female Jumper Wires    


Jumper wires: Versatile and easy to use

The end pin has been crimped and
soldered to the wire. Heat shrink
tubing insulates the connector.
(Click to enlarge)
Two jumper wires are connected
to an LED assembly.
(Click to enlarge)
The buzzer is connected to the RAMB.
(Click to enlarge)

Having enough connectors and jumper wires on hand always seems to be a problem, especially with a lab full of creative students who design increasingly elaborate robotic applications. In this tutorial, I demonstrate how to make female jumper wires, which provide and easy and versatile way to connect sensors and output devices to your microcontroller.

Female jumper wires offer a bit more versatility than end connector cables. But with increased versatility here comes a greater chance of incorrectly plugging the jumper wires into your motherboard. Doing this can damage your external devices, so make sure that you fully understand the power requirements and pin layouts of the RAMB and BX-24 before using these wires.)

 
  • See pages 175-178 in my book for a detailed description of the electrical systems of the RAMB motherboards and the BX-24 microcontroller.

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 about it. Actually, once you've soldered the end pins to the bare wires, the jumper wires are practically finished -- all that's left to do is add some heat-shrink tubing for insulation purposes.

In this tutorial I will also demonstrate how these these jumper wires can be used to connect external devices such as piezo buzzers and LEDs to the RAMB. I've even added a special section on using male-to-female jumper wires with the RAMB II -- Robodyssey's new BX-24 motherboard.

 

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Table of Contents for this Page

  1. Gather Your Materials
  2. Solder the End Connector Pins to Bare Wire
  3. Add the Shrink Tubing
  4. Connect Output Devices to the RAMB via Jumper Wires
  5. Special Section: RAMB II Considerations


Gather Your Materials
The jumper wires we'll make here are a designed to connect sensors and output devices (such as buzzers, LEDs, sonic rangers, LCD panels, etc.) into the signal and ground pins of Robodyssey's RAMB and RAMB II motherboards. To make our jumper wires you'll need the following supplies and tools:

 
  • See pages 175-178 in my book for a detailed description of the electrical systems of the RAMB and BX-24.

  1. Grab two wires that you want to make into a female jumper wires. The wire can either be solid or stranded. In this tutorial, I will use solid 22 AWG (American Wire Guage) wire but stranded wire will work just as well. The length of the wire is unimportant, but they should be the same length. For the record, the length of the wires I am using today is about 8cm.

    I will use yellow and black wires, as shown in Figure 1. These colors correspond to signal and 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 and the darkest is ground.)

  2. For this project we'll need the usual soldering and crimping tools pictured in Figure 2. These include a wire stripper, needle-nose pliers, pin crimper tool, "third hand", solder, soldering iron, and soldering iron tip cleaner. (See my tutorial on soldering end pins for more details about using these tools.)

  3. 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 four end connector pins.

  4. Heat shrink tubing (Figure 4). (Jameco P/N 71327.) This shrink tubing is pretty small (1.5mm inner diameter before shrinking) and is used to electrically insulate the metal end connectors -- we don't want a short, do we? Shrink tubing also adds strength to the solder joint. We'll need four pieces of shrink tubing, each about 2cm in length. See Figure 5.

  5. We will need a heat gun (pictured in Figure 6) to heat the shrink tubing as explained in Section 3 below. If a heat gun is unavailable, a match or lighter will do.

  6. When we are finished making the jumper wires we'll need some device with which to test the jumper wires. I use the jumper wires made here to connect a piezo buzzer (Figure 7) and an LED assembly (Figure 8) to the RAMB and program the BX-24 to make the buzzer beep and the LED flash.

For a list of part numbers, prices, and more tools see my Equipment Buying Guide.

Click on the images below to enlarge them.


Figure 1. I'll use solid yellow and
black wire (22 AWG) for this project.


Figure 2. Some tools needed for the job.


Figure 3. End connector pins will be
crimped and soldered to bare wires.


Figure 4. Shrink tubing is used to
electrically insulate the end connector pins.


Figure 5. For this project, we'll need
four pieces of shrink tubing, each
about 2cm in length.


Figure 6. A heat gun is needed to
heat the shrink tubing.


Figure 7. I'll use the jumper wires to
connect one of these buzzers to the RAMB.


Figure 8. I'll also use the jumper wires
to connect an LED assembly to the RAMB.

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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.

  1. 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 one in Figure 9.

Click on the images below to enlarge them.


Figure 9. End connector pins have been
crimped and soldered to bare wires.

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Add the Shrink Tubing
We are now ready to insulate and strengthen the end connector pins with plastic shrink tubing.

    (At this point we could have inserted our soldered connector pins into a plastic housing as I demonstrated in a previous tutorial. However, the jumper wire option offers the greatest flexibility when connecting output devices such as LEDs and buzzers.)

Heat shrink tubing is very cool stuff. Here's how to use it:

  1. Pick up a wire that has an end connector pin soldered onto the end and carefully slide a small piece of shrink tubing over the end of the wire as shown in Figure 10. A piece 2cm-long should do. The shrink tubing I am using (Jameco P/N 71327) has an inner diameter of 1.5mm before shrinking so the fit will be a little tight. Make sure no metal is showing except, perhaps, for the very tip of the end connector, as shown in the figure.

  2. Apply heat evenly to the shrink tubing with a heat gun as shown in Figure 11. The air from the gun is very hot -- be careful that you don't burn your fingers or worse: melt the shrink tubing! Move the gun from side to side to ensure even heating. (If you don't have a heat gun you can use a match, lighter, or candle. Just be warned that it is easy to burn or melt the tubing with an open flame.)

  3. When completed, tubing should shrink tightly around the end connector pin. The end of your jumper wire should look like the one in Figure 12. Repeat the above steps to cover the remaining end connectors with heat shrink tubing.

Click on the images below to enlarge them.


Figure 10. Slide the heat-shrink tubing
over the end connector pin. Make sure
no metal is exposed.


Figure 11. Shrink the tubing with a heat
gun. Be careful not to burn your fingers
and avoid melting the tubing, too!


Figure 12. The end of the jumper wire
is now tightly covered with shrink tubing.

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Connect Output Devices to the RAMB via Jumper Wires
It's now time to use the jumper wires to connect output devices (such as as LED's and buzzers) to the RAMB. Be certain that you fully understand the electrical systems of the RAMB and BX-24 before proceeding.

 
  • See pages 175-178 in my book for a detailed description of the electrical systems of the BX-24 and the RAMB.

  1. Because the female ends of newly made jumper wires can be a bit tight, I like to stretch them out first on a header pin before I connect them to electronic components. Figure 13 shows me exercising an end connector on one of the RAMB's header pins. Now that it is stretched out a bit, electrical components can be inserted more easily.

  2. Test your wires out now by plugging an output device into the jumper wires. You should follow the usual color conventions when wiring your device. For example, I will plug the lighter (yellow) wire into the positive (+) terminal of the device and the darker (black) wire into the negative (-) terminal.

    Figure 14 shows the proper way to wire a piezo buzzer. (Note the positive terminal is marked.)

    Figure 15 shows the proper way to connect an external LED assembly. Many LEDs have a flat on one side of have a notch to indicate which terminal is the negative one. You can also tell which is the negative terminal of the LED assembly pictured here because it is the one without the resistor. (See my tutorial on making external LED assemblies for more details.)

     
    • See page 176 in my book to learn more about color conventions.
    • See Chapter 3 in my book to learn how to program LEDs (light-emitting diodes).
    • See Appendix D in my book to learn how to program piezo buzzers and audio transducers.

  3. If you wish to have your output device always on (for example, you may want a super-bright LED to serve as a constant light source), then you could plug the jumper wires into the RAMB as shown in Figure 16. Note that the yellow wire is connected to one of the RAMB's unregulated power pins. As always, the black wire is connected to a ground pin.

  4. If you wish to be able to control your device with code (say you want the LED to flash on and off, or you want to program an audio transducer to play a song), then you should plug the jumper wires into the RAMB as shown in Figure 17. Note the yellow wire is connected to one of the RAMB's signal pins. As always, the black wire is connected to a ground pin.

    Connecting the device in this way makes use of TTL programming. TTL stands for Transistor-Transistor Logic and simply means that we can control devices by sending out high and low signals. For most robotic TTL applications (including ones controlled by the BX-24), the high signal is +5V and the low signal is 0V.

Click on the images below to enlarge them.


Figure 13. I like to exercise newly-made
end connectors before using them.


Figure 14. A piezo buzzer is attached
in the proper way to the jumper wires.
Note the yellow wire is connected
to the positive (+) terminal.


Figure 15. An LED assembly is correctly
attached to the jumper wires. The negative
terminal is the one without the resistor.


Figure 16. This configuration will deliver
a constant voltage to the output device.
Note the black wire is connected to a
ground pin and the yellow wire to an
unregulated power pin.


Figure 17. In this configuration, we can
control the output device with code. The BX-
24 makes use of TTL: setting the signal pin
to high (i.e., +5V) will turn the device on.
Setting it to low (i.e., 0V) will turn it off.

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Special Section: RAMB II Considerations
If you use Robodyssey's latest BX-24 motherboard -- the RAMB II -- connecting external devices is even easier than described above. Of course, the jumper wires you just made are 100% compatible with the new motherboard.

Below I illustrate some of the ways jumper wires can be used with this new and improved motherboard.

  1. You can use the jumper wires described in the above tutorial on the RAMB II just a would on the RAMB; simply plug them in and you are ready to go.

    • Figure 18 shows jumper wires plugged into the ground and unregulated power pins on the RAMB II. (Compare this to Figure 16 in the above section.) In this configuration, an output device would be always on.

    • Figure 19 shows jumper wires plugged into the ground and signal (TTL) pins on the RAMB II. (Compare this to Figure 17 in the above section.) In this configuration, an output device could be controlled with code from the BX-24.

  2. The RAMB II allows us to connect bare wire to one of its many female sockets, which deliver power, ground, and signal just by plugging in. (See my tutorial on the unique features of the RAMB II for more details.)

    Figure 20 shows two jumper wires that can be used with the RAMB II. The wire's bare ends plug directly into the female sockets on the motherboard. The ends with connector pins are used to connect to the external device. For example, Figure 21, shows a piezo buzzer connected to these simple jumper wires.

    With these bare jumper wires, external devices can be plugged into the RAMB II with great ease. Here are two examples:

    • Figure 22 shows a piezo buzzer plugged into the ground and unregulated power pins of the RAMB II. (Figure 23 shows a close-up of the wires plugged into the motherboard.) When the RAMB II is powered up, the piezo will continuously emit a loud ear-piercing sound. This configuration is identical to the one shown in Figures 16 and 18.

    • Figure 24 shows a piezo buzzer plugged into the ground and one of the signal pins of the RAMB II. (Figure 25 shows a close-up of the wires plugged into the motherboard.) In this configuration, the piezo buzzer can be programmed to turn on and off with computer code. This configuration is identical to the one shown in Figure 17 and 19.



    Again, see my RAMB II tutorial for more details about this exciting new BX-24 motherboard.

Click on the images below to enlarge them.


Figure 18. Jumper wires work with the
RAMB II, too! Compare this to Figure 16.


Figure 19. Jumper wires work with the
RAMB II, too! Compare this to Figure 17.


Figure 20. The RAMB II will accept
jumper wires with bare ends!


Figure 21. A piezo buzzer is attached
to a jumper wire with one end
connector and one bare end.


Figure 22. The piezo buzzer is plugged
into a ground socket and the unregulated
power socket to produce a continuous sound.
Compare this to Figures 16 and 18.


Figure 23. A close up of the connection
shown above in Figure 22.


Figure 24. The piezo buzzer is plugged
into a ground socket and a signal (TTL)
socket (BX-24 pin 12, RAMB pin 7).
Compare this to Figures 17 and 19.


Figure 25. A close up of the connection
shown above in Figure 24.

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Copyright 2006, Chris D. Odom. All Rights Reserved