Welcome!

This is BCC's unofficial EVC Truck repository, where all of the files for instrumentation on the truck are stored.

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The File Tree

• arduino-libraries contains a couple of the library files used for the Arduino Mega. This is just for reference. Honestly, this might not even be necessary at this point.
• data contains the data files of our test runs.
• docs contains important documents or manuals.
• i2c-gps-programs contains code for the Arduino Mega and UNO to display text on the LCD (using the I2C communication protocol) while getting GPS data (which uses UART serial).
• imgs contains images that are displayed on this document.
• mega contains code for the Arduino Mega.
  • canbus123 is the most recent program as of summer 2024 for the truck.
• test-programs contains basic programs to demonstrate the basic functionality of the hardware.

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Hardware Overview

• The GPS uses the UART serial communication protocol, and the LCD uses I2C.
• The proto shield is used to help with wire management.

List

• Electrocookie Mega R3 Proto Shield
• Arduino Mega
• SparkFun CAN-BUS Shield
• SparkFun 20x4 SerLCD - RGB Backlight (Qwiic)
• SparkFun GPS Receiver EM-506
• SparkFun Bi-Directional Logic Level Converter
• Breadboard
• Jumper wires
• Micro Center 128GB microSD Card

Hookup Guidelines

Connecting the GPS

Plug in the 5-wire connection to the GPS module and to the GPS port on the CAN-BUS Shield. The second and the third wire should be stripped and have male ends soldered onto them, which is shown in the image below:

The two wires should be connected to the appropriate pins:

GPS Module	Proto Shield (or Mega)
Third (middle) wire	Pin 14
Second wire	Pin 15

Establishing the SD Card Connection

If the prototyping shield isn't being used, the following are the pins you'd connect on the CAN-BUS and the Mega:

CAN-BUS	Mega
10	53
13	52
11	51
12	50

If the prototyping shield is being used, the following are the pins you'd connect with female-to-female jumper wires:

Proto Shield	Proto Shield
10	53
13	52
11	51
12	50

Connecting the LCD

Reference this hookup guide in general. To hook up the LCD for I2C, see this part of the hookup guide. Here's the diagram. For some reason, the diagram doesn't include the connections for LCD GND and RAW, so we guessed those.

LCD	Breadboard	CAN-BUS
GND	A27
RAW	A15
SDA	D30 (LV1 on the Logic Level Converter)
SCL	D29 (LV2)
	E16 to -2 (from top right)
	D28 (LV)	3.3v
	H28 (HV)	5v
	-1 (top right)	GND
	E15	VIN
	H30 (HV1)	SDA
	H29 (HV2)	SCL
	J27 to -27 (from the right)

Orient the Logic Level Converter as shown in the image below:

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Displaying Truck Metrics

Metric	Working on Display?	Data is From
Speed (mph)	Y	GPS
RPM	N	Motor controller
Battery temperature (C)	Y	BMS
Motor controller temperature (C)	N	Motor controller
Pack current	Y	BMS
Pack voltage	Y	BMS
Lowest cell voltage	Y	BMS
Lowest cell voltage ID	Y	BMS
Kilowatt-hour	Y	BMS
Trip (miles)	Y	GPS
Time	-	-
Latitude/Longitude	-	GPS
Altitude (meters)	-	GPS
Course (degrees)	-	GPS
MPGe	-	BMS
Power	-	BMS

LCD Layout

• (17, 1) is the lowest cell voltage ID
• (14, 2) is the lowest cell voltage

	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19
0	x	x	.	x	x	M	P	H		R	P	M	:	x	x	x	x
1	B	T	:	x	x	x	C		M	C	:	x	x	x	C			#	x	x
2	x	x	x	A		x	x	x	.	x	V				x	.	x	x	x	V
3	x	x	x	.	x	K	W	H		T	R	I	P	:	x	x	x	.	x

Connecting to the Battery Management System (BMS) on Arduino

• In the Arduino code, make sure the baud rates are the same as the BMS via CANSPEED_125.
• In order to retrieve metrics from the BMS, the BMS must be set up with the appropriate parameters under a message identifier. Keep in mind certain parameters take up 2 bytes instead of 1. Within the Arduino code, if statements catch messages on the CAN bus protocol. By accessing the appropriate byte from the message identifier, we can retrieve the metric we need from the BMS.
  • Take a look at this if statement:

    if (message.id == 0x123) {
        int CDEC = 0; 
        for (int i = 0; i < 2; i++) { // (1)
            int MDATA = (message.data[i]); 
            CDEC = CDEC + (MDATA*(pow(256, 1-i)));
        }
        lcd.setCursor(0,1); 
        lcd.print("BT:");
        lcd.print(message.data[3],DEC); // (2)
        lcd.print("C");
        lcd.setCursor(17,1);
        lcd.print("#");
        lcd.print(message.data[2],DEC); // (3)
        lcd.setCursor(13,2);
        lcd.print((float)CDEC/10000,3); // (4)
        lcd.print("v");
    }

    • (1) Gets the low cell voltage by checking bytes 0 and 1.
    • (2) Displays the highest battery temperature.
    • (3) Displays the low cell voltage ID.
    • (4) Displays the low cell voltage from (1).
• You'll see some for statements that iterate on the same initialization value. This is intentional. Apparently it gets rid of leading zeroes.
• Check the editing-canbus-messages document under docs for more information.

CAN Addresses on the BMS

These can be modified on the BMS software.

0x03B	Byte	Metric
	0	Pack current
	1
	2	Pack inst voltage
	3
	4
	5
	6
	7

0x3CB	Byte	Metric
	0	Pack DCL
	1	Pack CCL
	2
	3	Simulated SOC
	4	High temperature
	5	Low temperature
	6
	7

0x6B0	Byte	Metric
	0
	1	Pack SOC
	2	Pack resistance
	3
	4	Pack open voltage
	5
	6	Pack amphouts
	7

0x123	Byte	Metric
	0	Low cell voltage
	1
	2	Low cell voltage ID
	3	High temperature (battery)
	4
	5
	6
	7

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Todo

• Get RPM and motor controller temperature from the motor controller to display on LCD
• Ensure that the data printed to the SD card is formatted properly
• Radio or music player capabilities

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