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Power Board

The Power Board distributes power from the battery to the rest of the kit. It provides six individual general-purpose 12V power outputs along with a separate power connector for the Raspberry Pi and servos.

It also holds the internal On|Off switch for the whole robot as well as the Start button which is used to start your robot code.

Board diagram

Power Board Diagram

Connectors

There are six power output connectors on the board, labelled L0–L3, H0, and H1. These can supply around 11.1V (±15%). The "H" connectors will supply more current than the "L" connectors.

They should be used to connect to the motor board power input, though can also be used to power other devices. These are enabled when your robot code is started and can also be turned on or off from your code.

There are two 5V connectors that can be used to connect low-current devices that take 5V inputs, such as the Raspberry Pi.

There is also a Micro USB B connector which should be connected to the Raspberry Pi for control of the power board.

Finally, there are connectors for external Start and On|Off switches. You may connect any latching switch for the On|Off switch, or a push-to-make button for the Start button.

Tip

If you intend to use only the internal On|Off switch, a CamCon must be plugged into the On|Off connector with a wire connecting one pin to the other pin on the same connector. Your power board should already have one of these plugged in.

Indicators

LED Meaning Initial power-up state
PWR|FLAT Green when powered
Flashing red and green when the battery is low
Green
5V Green when 5V is being supplied Green
H0–1, L0–3 Green when the corresponding output is on 1
Red when the output's current limit is reached
Off
RUN|ERROR Orange on power-up, or USB disconnection
Flashing green when ready to run
Solid green when running or booting
Orange

On power-up and when waiting for the start button, the Power Board will beep once.

If the Power Board starts beeping (and all the outputs turn off) then this means that the whole board's current limit has been triggered.

Controls

Control Use
ON|OFF Turns the power board on, when used in conjunction with an external switch
START Starts your program

Case dimensions

The case measures 83x99x24mm. Don’t forget that the cables will stick out.

Specification

Parameter Value
Main battery fuse current 40A
Overall current limit2 30A
High current outputs (H0-1) 20A
Low current outputs (L0-3) 10A
Motor rail output voltage (nominal) 11.1V ± 15%
Total 5V output 2A

Designs

You can access the schematics and source code of the firmware for the power board in the following places. You do not need this information to use the board but it may be of interest to some people.


  1. The outputs only turn on when your program runs (specifically, when the Robot object is created). 

  2. If overall current limit is exceeded, the Power Board will turn off and start beeping.