Many FTC teams rely on basic wiring techniques and tools to set up the electronics for their robots. However, these basic methods and materials will not suffice for more advanced wiring requirements. Whether your team is utilizing more advanced sensor arrays, require better protection for the robot's wiring, or desire a more industrial and sleeker wiring setup that is easy to maintain, you will need different resources and skills for the job. This instructable aims to outline what is needed for industrial wiring, how to wire advanced sensors, an advanced and professional wire splicing technique, and how you can keep your wires safe and organized.
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Step 1: Useful Tools and Materials
Before you can start wiring your robot or conduct the techniques laid out in this instructable, you will need the right tools for the job. Below is a list of all the things the team uses, as pictured above:
- A soldering station (image 1).
- A magnifying glass stand (image 2).
- Solder (image 3).
- Dikes, pliers (including needle-nose pliers), and wire strippers (image 4).
- Wire (image 5).
- Wire ends (image 6).
- A heat gun or blow dryer and heat shrink (image 7).
- Terminal hubs (for limit switches) and wiring pins (image 8).
- Zip ties and zip tie mounts and sheaths (images 9 and 10).
- Limit switches (image 11).
- Safety glasses (image 12).
Step 2: Wiring Advanced Sensors
Sensors such as limit switches and color sensors are delicate to wire due to their small size, so special caution should be taken when doing so. Below is a list of tips for conducting such procedures:
- Start with making a schematic (image 1). Having a wiring plan is important so that you have a guide to work with when you begin the process. Autodesk Eagle is a free-for-students option for schematic-making software and is what our team uses, but hand-drawing schematics may also be a good option; ideally, it is a good idea to sketch out the basic flow of the schematic and then create a finalized, clean version of it using software.
- Use heat shrink, always (images 2 and 3). Due to the delicate nature of these types of sensors, protecting the wires is a must (more on this in Step 4). Be sure to put the heat shrink on before soldering the wires.
- Avoid making wire ends as much as possible. The process is difficult and easy to mess up for those who are unsure of what they are doing. Aim to use pre-made ends.
- Limit switch wiring techniques - these sensors are particularly difficult to wire, so the following tips should be taken into account:
- When soldering into a limit switch with a hole through the electrical connector, put half the cable through, then use pliers to clamp both sides of the wire together (images 4 and 5).
- If you are wiring multiple limit switches, use a terminal block to hold the wire - this will let you test everything and adjust as needed should your initial wiring be incorrect.
Step 3: NASA Splicing
For some sensors, strong wires are a must - they may undergo a lot of stress, such as if the sensor moves and stretches the wire, or they may need to survive collisions. To insure that wires are strongly soldered together, the Lineman or NASA splice is an important technique to use.
The following is a step-by-step guide for NASA splicing:
- Twist two cable ends together (image 1).
- Wrap the remaining ends around the wires, resulting in three-to-four full wraps without any gaps (image 2).
- Flow solder across the created joint (image 3).
For more information on NASA splicing, go here (pictures were retrieved from this website).
Step 4: Protecting Wires and Cable Management
It is important to keep in mind the delicacy of your electronics and wiring when undergoing the process. Should a wiring setup break during a competition, it may cost you a victory and makes for a difficult repair procedure outside your usual working space.
Cables have a minimum bend radius, the smallest radius it can be bent, and it is important to keep this radius in mind when wiring. Generally, this bend radius is around six times the diameter of the wire. Research your wire to determine its minimum bend radius.
To strengthen wires and protect them from the elements, using heat shrink tubing is recommended.
Another key aspect of maintaining your wiring setups is cable management. You should make sure that your wires are tidy and away from danger so that they are not damaged and are easier to maintain. Whats more, a cleaner wire setup looks more professional and industrial. Your wiring should have a centralized flow to the main power hub so that they are easy to keep track of and get to.
Useful tools for cable management include:
- Zip ties and tie mounts for keeping cables tied down.
- Wire sheaths and tubing covers for protecting wires and keeping wires that go to the same electronics together.