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Specifications (from the EE Team)

Overall Hardware Architecture (taken from https://uwarg-docs.atlassian.net/wiki/x/AoCsmQ )

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Background

The drone uses a battery pack containing 12 cells, where 2 groups of 6 cells are each connected in series (hence 6S).

...

  • Battery-related information relating to the voltages and currents

  • The voltage and current information are sent as 2 analog signals, which our microcontroller converts to digital ones via an Analog-to-Digital Converter (ADC).

  • Some other information is sent via the I2C protocol

Description

Info
  • MCU (STM32xX) in the top right is the microcontroller that we are writing the code to

  • Its job is to translate the messages it receives from the BQ76925 6s LiPo Battery Monitor boards and send the corresponding messages to the flight controller (FC) using the CAN protocol

Expand
titleWhy are we making this?

The FC needs this information to make other decisions, e.g. if a part is consuming too much power, or when to land

Specific Hardware Information (taken from https://uwarg-docs.atlassian.net/wiki/x/HYBXq)

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Info

The ports we are interested in:

  • PA9: SCL_1

  • PA10: SDA_1

  • PA7: SCL_2

  • PB4: SDA_4

  • PA12: CAN_TX

  • PA11: CAN_RX

Speculated ports:

  • PA3: Receives a digital signal representing whether an overcurrent occurred

  • PA5: Receives an analogue signal representing the cell voltages for cells 1-6

  • PB0: Receives an analogue signal representing the cell currents for cells 1-6

  • PB1: Receives an analogue signal representing the cell voltages for cells 7-12

  • PA2: Receives an analogue signal representing the cell currents for cells 7-12

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\uD83E\uDD14 Current Roadblocks

Note

Libcanard has a high learning curve. Neither the DroneCAN website nor the Libcanard repo has beginner-friendly tutorials. YouTube videos also won’t help directly

Tasks Break Down:

✅  Action Items

  •  etc.

\uD83D\uDEA9 Milestones

  •  Understand project specifications
  •  Understand the I2C protocol
  •  Understand the CAN protocol
  •  Understand DroneCAN
  •  etc.

Open Questions

  • Are our speculated ports correct?

  • What is transmitted over I2C?

  • What is the voltage range for the signals our MCU receives for the voltage and current info from the battery monitoring circuits?

  • How should the MCU beacon itself to the FC (i.e. so that the FC is aware that the MCU on the power module is there)?

  • What should be sent over CAN?

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\uD83D\uDD17 Reference materials

Relevant protocols

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