Electronics Layout

Setting up the electronics layout for the robot is a very important task, for without it the robot simply would not run at all. If it is made badly, it will cause more trouble in debugging the robot and perhaps cause the robot to cease to function as well.

Location, Location, Location

Location of the electronics board on the robot is quite important. Ideally, the board should be on a flat surface that is open enough to lay out the various components freely, but small enough to not be a waste of space. The board should also be free of any moving components, especially motors to remove the electromagnetic fields motors create when in use.

Laying it Out

Components

Before any holes are to be drilled for the board, it is required that the board be laid out with all components that are to be used. Ergo, if you plan to use five Victors, then five Victors need to be acquired and laid out with the rest of the board.

Here is a list of the most commonly used components on the electronics board:

• cRIO
• Power Distribution Board
  • Includes main breaker
• Digital Sidecar
• Analog Breakout
• Motor Controllers
• Relays

Sensors and other things such as pneumatic devices usually do not have to be included unless it has been decided that such device will be mounted on the same board and cannot be mounted elsewhere.

The overall key to laying out the electronics board is remembering a few simple things, but the key idea is - short wire. Where ever you place a component, there is one or more wires going to or from it. Having components wired together placed closer together allows for a shorter wire and leads to less money spent on wire and the possibility for electronic signal distrubance.

Keep in mind when placing the following components as they have several wires going to and from them:

• Motor Controllers
  • Three Wires
    • Power
    • Motor
    • PWM Cable
• Relay
  • Three Wires
    • Power
    • Motor
    • PWM Cable
• Power Distribution Board
  • Any number of wires leading to motor controllers or relays
  • Wires to cRIO, router, and/or camera

Note: PWM cables are going from the Digital Sidecar to motor controllers or relays are often too long and get in the way of of cooling fans found on motor controllers. Make sure to leave room to place PWM cables where they will not get in the way.

Marking it Up

Once the board is laid out to best configuration possible, the holes to mount the components should be marked using a thin Sharpie. As said marking device may be inadequate to go through mounting holes in some components, it may be required to "eye ball" it.

After holes for one component are marked, it is suggested that the area underneath the component is labeled with the name of the component to remind the builder what goes in the spot after the holes are drilled.

Drilling the Holes

After all the holes for each and every component are marked, the holes for them can be drilled out. Make sure that this is done away from the components as getting any debris in the components could cause a failure at any time. Keep in mind that some components may require the use of a different screw size, ergo a different drill bit size.

Mounting the Components

Mounting the components is quite a simple task that could be given to any freshmen. All that is required is a screwdriver, screws, and nuts. Note that nuts may be included with some components already.

Wiring the Components

Wiring is perhaps the single time consuming task on constructing the electronics board other than laying out the components. Wires should be cut so that they are short and follow paths in the board so that the board is neat and clean. The path of each wire should be obvious so it can be seen where it leads to.

It is highly reccommended to label where everything is connected. For example, if a motor controller is added, there should be a label saying what this controls on:

• Motor
• Motor Controller
• Power Distribution Board (breakers)
• PWM Cable

Pre-Test Lookover

Before applying any power to the board, double check the wiring. This is stressed as this is the last point to catch any errors for incorrect wiring. Once power is applied, any components that are wired wrong will result in magic blue smoke and a broken, expensive component.

Also check to make sure that no debris from drilling the mounting holes is caught in any open cooling vents such as the motor controllers.

Final Test

Once everything is approved as safe and correct, power from a battery can be applied. If no magic blue smoke is present and all status lights seem to be happy and "go", then the board seems to be wired correctly and is ready to be mounted on a robot.