2 layers76.9 × 38.8 mm
4 layers43.4 × 19.4 mm
CANduino
FletcherJ1/CANSpeedo3CAN based digital speedometer for Alfa Romeo Giulietta
- Size
- 43.4 × 19.4 mm
- Copper layers
- 4
- Thickness
- 4.69 mm
- Parts
- 26
- Nets
- 41
- Pads
- 102
- Tracks, vias
- 218, 32
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 5 (file 20210126)
- Created
- 13 Jul 2021
- Updated
- 14 Jul 2021
Overview
CANduino is an open-source printed circuit board by FletcherJ1, from the FletcherJ1/CANSpeedo repository on GitHub, published under the CC0-1.0 licence. It is a 4-layer board of 43.4 × 19.4 mm with 26 parts on 41 nets, routed with 218 tracks and 32 vias.
It is built around the ATMEGA16M1-MU, TPS2115AIPWRQ1 and ECS-160-8-33B-CTN-TR, with the MM5Z5V1T5G and SMBJ9.0CA-Q among its other parts. Its parts include 11 capacitors, 4 resistors, 3 ICs, 2 connectors and 1 diode. It belongs with the AVR (ATmega, ATtiny) boards of this library.
Main components
5ATMEGA16M1-MU
QFN-32-EP(7x7)-40℃~+85℃ 10bit 10bit 16KB 16MHz 1KB 2.7V~5.5V 512Byte 8 Bit AVR Built-in FLASH QFN-32-EP(7x7) Microcontrollers (MCU/MPU/SOC) ROHSMicrochip TechnologyMicrocontrollers (MCU/MPU/SOC)
TPS2115AIPWRQ1
TSSOP-8-40℃~+85℃ 1A 2.8V~5.5V Operating status indication、Adjustable current limiting TSSOP-8 Power Management - Specialized ROHSTexas InstrumentsPower Distribution Switches
ECS-160-8-33B-CTN-TR
SMD3225-4P-40℃~+85℃ 16MHz 60Ω 8pF ±10ppm ±20ppm SMD3225-4P Crystals ROHSECSCrystals
MM5Z5V1T5G
SC-791 Independent 2uA@2V 4.8V~5.4V 5.1V 500mW 60Ω SC-79 Zener Diodes ROHSonsemiZener Diodes
SMBJ9.0CA-Q
SMB(DO-214AA)-55℃~+150℃ 10uA 12.3V 195A@8/20us 20V 600W 9V Bidirectional TVS SMB(DO-214AA) ESD and Surge Protection (TVS/ESD) ROHSBournsESD And Surge Protection (TVS/ESD)
README
README.mdOBD Digital Speedometer
This project sparked from not having a digital speed readout on the dashboard of my car (Alfa Romeo Giulietta) when driving in 'Normal' and 'Dynamic' mode. This uses the OBD-II port to read the vehicle speed and then print the speed onto the radio message. This radio message is sent from the radio module to the dashboard and requires the 'Radio Repetition' setting in the dashboard to be enabled for the message to be displayed. This message is sent only when the car is on and is sent at a 2hz rate.
The end result of this is shown below while I was testing the display output:
Vehicle information
The CAN network used is a 50Kbps network and is defined as the CAN-B network on the car (pins 1 and 9 on the OBD-2 port).
The car it has been tested on has 16" wheels and is a 2011 model. I'm not sure if the wheel diameter affects the speed value provided by CAN so the variable SPEED_DIVIDER_MPH might need to be changed to suit other vehicles and wheel diameters.
Hardware
The hardware used is centered around an ATmega16M1 because it has an in-built CAN controller and works with the Arduino framework. It also helps keep the PCB as small as possible and keeps components count down.
There is a power switch for powering via either the car through the OBD port or via the ICSP header. This isn't really needed but added to make software development slightly easier.
The PCB is designed using Kicad 5.99 and is made to fit an OBD-2 case found on eBay.
The PCB is a 4 layer design because it didn't cost any more than a 2 layer design from JLCPCB.
This fits in the car and still allows for the diagnostic panel to fit over the plug when it is plugged in.
Data dumps
I've also included some data dumps (under the /Dumps folder) containing can information when the car is in various states. Feel free to use this information as desired to decode additional parts of the cars CAN data.
I also included a file in the dumps with additional information I found and some more decoded CAN messages. This might be confusing to read through but should give some ideas.
I found plotting the data with graphs, I used Flow CSV Viewer, quite helpful to find multi-byte variables as well as what the variable may represent based on how the data changes.
Libraries Used
Credits
Parts
26| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 100nF | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C3, C4, C6, C12, C15 |
| 3 | 1uF | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C1, C5, C13 |
| 2 | 12pF | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C7, C11 |
| 2 | MountingHole | MountingHole:MountingHole_6mm_Pad | H2, H3 |
| 1 | 10K | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R4 |
| 1 | 10uF | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C2 |
| 1 | 1R | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R1 |
| 1 | 50R | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R3 |
| 1 | 700R | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R2 |
| 1 | ATMEGA16M1-MU | SamacSys_Parts:QFN65P700X700X100-33N | H1 |
| 1 | Conn_01x04 | Connector_PinHeader_1.27mm:PinHeader_1x04_P1.27mm_Vertical | J2 |
| 1 | Conn_02x03_Odd_Even_MountingPin | Connector_PinHeader_2.54mm:PinHeader_2x03_P2.54mm_Vertical | J1 |
| 1 | ECS-160-8-33B-CTN-TR | SamacSys_Parts:ECS160833BCTNTR | Y1 |
| 1 | MM5Z5V1T5G | SamacSys_Parts:SODFL1608X70N | Z1 |
| 1 | SMBJ9.0CA-Q | SamacSys_Parts:DIONM5127X229N | D1 |
| 1 | TJA1050T_CM,118 | SamacSys_Parts:SOIC127P600X175-8N | IC4 |
| 1 | TPS2115AIPWRQ1 | SamacSys_Parts:SOP65P640X120-8N | IC1 |
| 1 | ZXTR2105FFQ-7 | Package_TO_SOT_SMD:SOT-23_Handsoldering | U1 |
Questions
How big is the CANduino PCB?
It measures 43.4 × 19.4 mm and has 4 copper layers, 4.69 mm thick.
What parts does the CANduino use?
26 parts, built around the ATMEGA16M1-MU, TPS2115AIPWRQ1, ECS-160-8-33B-CTN-TR and MM5Z5V1T5G. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the CANduino KiCad files?
From the FletcherJ1/CANSpeedo repository on GitHub, at the commit this page was made from: the board is Hardware/CANduino.kicad_pcb and its schematic Hardware/CANduino.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the CANduino design in my own project?
Its repository publishes it under the CC0-1.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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