An arduino code that reads Honda OBD Protocol and translates it to ELM327 protocol. I use Torque app to read and display the data on my android phone (via bluetooth), and a LCD (2x6) to display it on my car's dashboard.
Please refer to the screenshots below.
- Datalogging
- Diagnostics
- Trip Computer
- Etc
- Honda ECU's before 2002
- hobd_uni - unified code for ELM bluetooth and LCD display with other improvements.
- hobd_elm - implements Honda OBD to ELM OBD2 protocol (bluetooth) - not updated
- hobd_lcd - implements Honda OBD to LCD display - not updated
- UNI_wiring.png - Unified wiring diagram for arduino UNO (compatible)
Honda 3 Pin DLC Arduino Uno
Gnd --------------------- Gnd
12 --------------------- Vin
K-line ------------------ Pin12
HC-05 Bluetooth Arduino Uno
Rx ---------------------- Pin11
Tx ---------------------- Pin10
LCD 16x2 Arduino Uno
RS ---------------------- Pin9
Enable ------------------ Pin8
D4 ---------------------- Pin7
D5 ---------------------- Pin6
D6 ---------------------- Pin5
D7 ---------------------- Pin4
VO ---------------------- 10k Potentiometer ( 5V to Gnd)
Piezo Buzzer Arduino Uno
( ) --------------------- Pin13
(-) --------------------- Gnd
Tact Switch Arduino Uno
( ) --------------------- Pin17 (A3)
(-) --------------------- Gnd
Voltage Divider Arduino Uno
12V divider circuit ---- Pin14 (A0)
(680k ohms and 220k ohms)
Honda 3 Pin DLC Arduino Uno
Gnd --------------------- Gnd
12 --------------------- Vin
K-line ------------------ Pin12
HC-05 Bluetooth Arduino Uno
Rx ---------------------- Pin11
Tx ---------------------- Pin10
Honda 3 Pin DLC Arduino Uno
Gnd --------------------- Gnd
12 --------------------- Vin
K-line ------------------ Pin12
LCD 16x2 Arduino Uno
RS ---------------------- Pin9
Enable ------------------ Pin8
D4 ---------------------- Pin7
D5 ---------------------- Pin6
D6 ---------------------- Pin5
D7 ---------------------- Pin4
VO ---------------------- 10k Potentiometer ( 5V to Gnd)
- Added button for changing page (5ms) and changing ecu mode (3s).
- Added Fault codes reader @ lcd page 3
- Added LCD @ I2C support
- #define LCD_i2c TRUE // Using LCD 16x2 I2C mode
- Added direct HOBD access API (ELM mode) used for undefined PIDs on OBD2
- // direct honda PID access
- // 1 byte access (21AA) // 21 = 1 byte, AA = address
- // 2 bytes access (22AA) // 22 = 2 bytes, AA = address
- // 4 byte access (24AA) // 24 = 4 bytes, AA = address
- Added direct Arduino Pin access API (ELM mode) used for keyless entry and other stuff
- // set arduino pin (ATSAPNNX) // NN = pin, X = value (value is 1 or 0)
- // get arduino pin (ATDAPNN) // NN = pin
- Tested on P2T ODB2 stock and P30 ODB1 chipped
- Add 128x64 LCD @ SPI support
- Add 20x4 LCD @ I2C support