id3esp32obd2

The id3esp32obd2 is an ESP32 based DIY OBD2 Bluetooth dongle and an Android app to show diagnostics data from a VW ID.3 car on an Android device.

Watch the device in Version 1.0.0 on YouTube

The following diagnostics data values are supported at the moment:

SOC (BMS)
Car operation mode
ODOMETER
VIN
Speed
Driving mode position
HV auxiliary consumer power
HV battery main temperature
HV battery circulation pump
HV battery voltage
HV battery current
HV dynamic limit for charging
HV Total charge
HV Total discharge
HV battery capacity
12V battery voltage
HV PTC heater current
Outside temperature
Inside temperature
Cruising range
Charging state
CO2 content interior
GPS time
GPS height
GPS latitude
GPS longitude

WARNING:

Connecting something to your VW ID.3 is your own risk and do this ONLY, if you know, what are you doing. If you make a mistake, it could be a very expensive mistake.
This is no a complete ISO-TP and/or UDS implementation. It is just enough to receive some data from a VW ID.3. I'm no CAN expert, just a beginner

License and copyright

Appendix

Hardware

ESP-WROOM-32 NodeMCU (Board manager: ESP32 Dev Model)
SN65HVD230 CAN transceiver (60 Ohm resistor R2 between CANHigh and CANLow was removed)
OBD2 Connector cable (Plugged in to the OBD2 female connector below the steering wheel)
VW ID.3 Car (Code was developed and tested on a ID.3 Pro S)
Two resistors (470k, 100k) for a voltage divider to measure the 12V car battery voltage on an ESP32 analog pin
LM2596 Step down voltage converter (to convert the 12V car battery to 3.3V as a power supply for the ESP32)
Android device with the self-made app: id3esp32obd2 (https://github.com/codingABI/id3esp32obd2/id3esp32obd2.apk)

Power consumption: 0.6W (0.3W when Android device is not connected), 0W when powered off by the toggle switch S1

OBD2 and power supply

The VW ID.3 has an ODB2 female connector below the steering wheel:

The id3esp32obd2 uses a male OBD2 connector and pin 16 (=12V), pin 5 (=GND) to power up the ESP32 (Converted down to 3.3V by a LM2596). Pin 6 (=CAN High) and 14 (=CAN Low) are used to access the CAN bus.

The 12V line can be switch on and off with the toggle switch S1.

Device description

An ESP32 has a builtin CAN controller, but needs an additional CAN transceiver. The ESP32 based id3esp32obd2 uses a SN65HVD230 CAN transceiver.

The red marked 60 Ohm resistor R2 between CANHigh and CANLow was removed.

The ESP32 waits for the "allowed" Android device connecting via Bluetooth (The "allowed" Android device can be defined in secrets.h). After connecting with the "allowed" Android device the ESP32 requests CAN data and forwards the response via Bluetooth. While the allowed Android device is connected the blue, ESP32 builtin led (Pin 2) is enabled. When the Android device disconnects the Bluetooth connection the CAN requests will be stopped.

WARNING Do not lock the car without disconnecting the Bluetooth connection or power off the device by the toggle switch S1, because the VW ID.3 may triggers a car alarm, if CAN requests are received in a locked state.

The id3esp32obd2 waits 500ms between each CAN bus request, because I got weired responses when sending requests too quickly.

All components are soldered on two pieces perfboard (I had no single perfboard big enough) and the ESP32 is stacked over the SN65HVD230 and the buzzer.

The toggle switch S1 to power on/off the device in mounted on a wooden, black painted clothespeg and can be sticked on a the ventilation grille in the car. The unused pins of the OBD2 cable are protected by heat shrinking tubes.

The id3esp32obd2 is in a wooden self-made case.

The window in the case is to show the builtin leds (Blue led on pin 2 and red power led) of the ESP32.

Code

The code for the ESP32 was written with the Arduino IDE and can be found in the Arduino-Sketch folder

Schematic

The voltage divider R1/R2 is used to measure the 12V car battery voltage with an ESP32 analog pin.

Android App

To show the VW ID.3 diagnostics data sent by the device via Bluetooth an Android device with the app id3esp32obd2 app is needed. This app is a small app made with https://appinventor.mit.edu/ (Source code: App source code) for this project and was tested on a Samsung Galaxy S10 5G with Android 12 and Samsung Galaxy S23 with Android 13. To install the apk file you have to temporary allow the installation (Samsung: Settings->Apps->Top right dots...->Special access->Install unknown app).

Bluetooth pairing and selecting the device

Before you can use the app, you have to pair the Android device with the id3esp32obd2 device listed as "id3esp32obd2" in your Android Bluetooth management.

After launching the app, you have to connect to the previously paired Bluetooth device by pressing 🔗 to open the list "Bluetooth device" and select "aa:bb... id3esp32obd2" (aa:bb... would be the MAC address of your ESP32). To manually disconnect an existing connection you can select "Disconnect" in the list "Bluetooth device". Next time you start the app again, the connection to the last selected Bluetooth device will be restored automatically.

General usage

In the app you can switch between several dashboards with the left ⇦ and right ⇨ buttons. When you move to another dashboard it could take up to 1.5 seconds to receive first data for the new dashboard and it could take several seconds to receive all dashboard data. When you receive "ERR" all the time, the device could not get the requested data from the CAN bus. In this case you should check the Serial output of the ESP32 for more details.

Titlebar

In the title bar you can change the selected id3esp32obd2 Bluetooth device with 🔗, see the Bluetooth connection status "Connected" or "Disconnected", reset the ESP32 with ♺ or open the info screen with with ⚙