DEWBOT VI Electrical

While the motors and pneumatics are the muscles of the robot, the wiring is the central nervous system. Electrical wiring supplies power from the battery to the Power Distribution Board, from there to the Jaguar and Victor speed controllers and then on to the motors. Wires also take signals from the sensors to the either the Digital Side Car (for on/off signals) or to the Analog daughter board (position sensors) for processing by the cRio. This page covers the details of the Electrical system, please see [DEWBOT VI Electrical Team] for the build season notes.

DEWBOT VI Technical Information

There are a lot of details about the electrical system, to make it easy to understand we break the system in to multiple parts: Power, digital in, digital out, analog in, solenoids, and other.

Power

Power is supplied by a 12 volt, sealed lead-acid battery. It sits in a Tuffak box that is closed by a length of 2" velcro that runs around the battery and box. This means the battery will not come out of the robot even if it's upside down.

Power is routed via two Anderson high amperage disconnects through a 120 volt circut breaker to the Power Distribution Panel. The panel is supplied by FIRST and holds all of the breakers. Depending on the device we use 40, 30 and 20 amp breakers in the panel. #6 wire is used for all the main battery connections.

We use three different sizes of wire depending on the device. Large, #10 wire is used to connect all of the Jaguar motor contols. Each pivot has two motors, drive and steering. There is a Jaguar for each motor. The large wire has very little resistance and can carry the high current loads of the motors.

Wiring information as of 21 Feb. Document contains pictorial view of the wiring, circuit numbers and the amp rating for the breakers.

Digital Side Car Reminder

This is a reminder that the digial sidecar has pull up resistors on all the Digital IO ports. This means that all the pins report a TRUE even when there is nothing connected. All switches need to be set up to pull the signal low. Wires run from ground through the switch to signal.

Battery Care and Handling

Lead-Acid batteries (like the ones used by FRC) do not like deep discharge (10.5 Volts is deep discharge). This causes the chemistry in the battery to "wear out", leaving the battery weaker and eventually unable to take a charge. So, change your batteries often, don't stress them so much.

They also very much do not like staying even a little discharged for any length of time. A week at 50% discharge will cause measurable damage. So, recharge the batteries immediately after every use. (An unused battery can sit 2 to 3 months without any care, but at that point it MUST be charged up again, or it will be damaged).

Of course, handling them carefully:

• Lift by the case, never ever by the terminals or attached wires (their ears)
• Don't drop them - treat the case like it was fragile - it is

Make sure the wires stay firmly attached - a loose connection will suck down all the power (turning it to useless heat) making the robot seem to eat batteries fast.

Engineering Information

Motors

RS555vc Motor Specifications 12 V, 4 500 rev/min free, 0.11 N·m stall, 4.40 A stall, 0.19 A free => 13.29 W max. at 12 V.

RS555sh Motor Specifications

Sensors

Cherry Part CU103602, rotational sensors - used on each pivot to tell what direction it's pointing.

PSOC

PSOC carrier board pin outs This is the board made by e-Stop Electronics to make it easier to make connections.

Electrical

2010 FIRST electronics documentation

Jaguar Information What the lights mean on the Jaguar

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