Design

MSXII/MSXIV: Tritium Bridge Interface Board

Description

The Tritium CAN-Ethernet Bridge is expected to be used in the car for our Telemetry system. The bridge connects to the CAN bus of the car using a DB9 connector. On the same DB9 connector, power (VBAT), and ground are also used to power the bridge itself.

Requirements

• Supply VBAT (9-14V) to the Tritium Bridge via the DB9 connector

• Connect CAN to the DB9 connector

  • Similarly to controller boards, there should be a pass through for CAN

  • I.e. CAN should pass through the board (Dura-Clik to Dura-Clik), but also go to the DB9.

• Include the ability to terminate CAN (61R + 61R + capacitor, identical to Controller Board Rev 7)

• Include ESD diodes for CAN

• Include TVS diodes for VBAT

MSXII/MSXIV: Ubiquiti Bullet M2 Interface

Description

The Ubiquiti Bullet M2 is planned to be used for telemetry as our wireless access point in the car. Since the Bullet was not originally designed for this purpose, we need to find a way to power it with a clean and stable voltage supply. One potential complication is the Bullet is powered through the Ethernet jack (Passive PoE), so we need to include Ethernet

Requirements

• Voltage regulator for the Bullet (What is it’s minimum and maximum voltage?)

• One ethernet port for the Bullet, another to interface with the rest of telemetry

MSXIV: DC-DC Board

Description

We recently got Vicor DCM modules for our next vehicle. We should design a board according to their recommended circuits. They also have simulation tools available online.

Requirements

• Use their simulation tool to design the circuit

• Work with @Eric Chiang from the mechanical team to figure out cooling

• Include over-current protection (fuses) for the input and output of the DC-DC

MSXIV: Sensor Board

Description

Our mechanical team is hoping to sense a variety of information (still TBD) from the car for both modelling and validating our dynamics systems. These may include things like acceleration of the car, travel of the suspensions, the steering angle, temperature, pressure etc. Most of these signals will be analog (basically a potentiometer), so you would take in the inputs and allow them to be sent over CAN.

Requirements

• Develop a sensor board to interface with one or multiple different sensors

• Work with the mechanical team (@kevin bui) and the strategy team to determine what sensors we should include in our car.

Infrastructure: Current Sense Board

Description

To measure current using an oscilloscope (e.g. what does the current look like when I turn something on?), you would typically use a current probe. These current probes are costly (>$500 for basic ones), and the goal is to design something that could be used in place of a current probe.

Requirements

• Measure current using a shunt resistor for up to 20 A

• Have a way of changing the offset (optional) to calibrate the sensor

• Have a way of showing the current level is too high

• Connect to an oscilloscope using a BNC connector or PCB probe connector

• Maybe connect to a controller board for PC logging? Or we can use something simpler for this (e.g. arduino)

Array (Not PCB design)

Description

We’ve finalized our aerobody for MSXIV, and the mechanical team has laid out a preliminary solar array layout using the Sun Power Maxeon Gen III cells. We need to work with the mechanical team in finalizing the array layout, and figuring out where we want the connections to our cells, as well as what maximum power point tracker (MPPT) we’re going to use for the array.

Requirements

• Work with the mechanical team in refining a solar array layout

• Evaluate and select a MPPT

Modifying Existing Boards

GPS Board
https://uwmidsun.atlassian.net/browse/HW-202

Hardware Contact: @Mena Labib

Description

One of the connections for the GPS module was not connected to our microcontroller. This should be fixed by creating a new revision of the board.

Validation

BMS AFE Rev 5

Hardware Contact: @Taiping Li

Firmware Contact: @Former user (Deleted)

Description

BMS AFE Rev 4 was designed to feature more thermistor sensing capabilities, separate wires to power the board, and provide better thermal performances while discharging the modules. We also switched to a linear regulator for Rev 4, which proved to have used too much power compared to our switching regulator. Rev 5 was therefore designed to include the changes from Rev 4, but revert the regulator change to the original switching regulator + LDO design. This should therefore be tested and validated.

To Do

• Bring-up and validate the new AFE Rev 5

• Perform accuracy testing for thermistors and cell readings

• Test thermal performances during discharge

Power Distribution Rev 3

Hardware Contact: @Taiping Li

Firmware Contact: @Andy Jin (Unlicensed)

Description

Power Distribution was designed in the weeks leading up to the 2018 American Solar Challenge, and was supposed to go into the car but was ultimately not validated in time. The board mainly focuses on improving thermal performances at higher currents by using a better shunt resistor for current measurements and having larger copper areas. We also switched from the low side switching MOSFETs to a new high side switch.

To Do

• Bring-up and validate the new Power Distribution Board

• Integrate the board into the car

Debug

Front Lights Board

Description

The Lights Board (Rev 1) in the front enclosure of the car currently does not turn the left daytime running lights (DRL) on. Investigate this further and replace components or the board as necessary.