Thanks for your reply. I downloaded the Carloop OBD Publisher on GitHub. I included it below, the code appears to work, I just can’t understand how to decode it using the Wiki
#include “application.h”
#include “carloop.h”
#include “base85.h”
SYSTEM_MODE(SEMI_AUTOMATIC);
SYSTEM_THREAD(ENABLED);
void sendObdRequest();
void waitForObdResponse();
void delayUntilNextRequest();
void printValuesAtInterval();
void printValues();
String dumpMessage(const CANMessage &message);
bool byteArray8Equal(uint8_t a1[8], uint8_t a2[8]);
Carloop carloop;
int canMessageCount = 0;
// OBD CAN message IDs
const auto OBD_CAN_BROADCAST_ID = 0X7DF;
const auto OBD_CAN_REQUEST_ID = 0x7E0;
const auto OBD_CAN_REPLY_ID_MIN = 0x7E8;
const auto OBD_CAN_REPLY_ID_MAX = 0x7EF;
// OBD services / modes
const auto OBD_MODE_CURRENT_DATA = 0x01;
// OBD PIDs
const auto OBD_PID_SUPPORTED_PIDS_01_20 = 0x00;
// MIL = malfunction indicator lamp = check engine light
const auto OBD_PID_MIL_STATUS = 0x01;
const auto OBD_PID_FUEL_SYSTEM_STATUS = 0x03;
const auto OBD_PID_ENGINE_LOAD = 0x04;
const auto OBD_PID_COOLANT_TEMPERATURE = 0x05;
const auto OBD_PID_SHORT_TERM_FUEL_TRIM = 0x06;
const auto OBD_PID_LONG_TERM_FUEL_TRIM = 0x07;
const auto OBD_PID_ENGINE_RPM = 0x0c;
const auto OBD_PID_VEHICLE_SPEED = 0x0d;
const auto OBD_PID_TIMING_ADVANCE = 0x0e;
const auto OBD_PID_INTAKE_AIR_TEMPERATURE = 0x0f;
const auto OBD_PID_MAF_AIR_FLOW_RATE = 0x10;
const auto OBD_PID_THROTTLE = 0x11;
const auto OBD_PID_O2_SENSORS_PRESENT = 0x13;
const auto OBD_PID_O2_SENSOR_2 = 0x15;
const auto OBD_PID_OBD_STANDARDS = 0x1c;
const auto OBD_PID_ENGINE_RUN_TIME = 0x1f;
const auto OBD_PID_SUPPORTED_PIDS_21_40 = 0x20;
const auto OBD_PID_DISTANCE_TRAVELED_WITH_MIL_ON = 0x21;
const auto OBD_PID_COMMANDED_EVAPORATIVE_PURGE = 0x2e;
const auto OBD_PID_FUEL_TANK_LEVEL_INPUT = 0x2f;
const auto OBD_PID_WARM_UPS_SINCE_CODES_CLEARED = 0x30;
const auto OBD_PID_DISTANCE_TRAVELED_SINCE_CODES_CLEARED = 0x31;
const auto OBD_PID_ABSOLUTE_BAROMETRIC_PRESSURE = 0x33;
const auto OBD_PID_O2_SENSOR_1 = 0x34;
const auto OBD_PID_CATALYST_TEMPERATURE_BANK1_SENSOR1 = 0x3c;
const auto OBD_PID_SUPPORTED_PIDS_41_60 = 0x40;
const auto OBD_PID_MONITOR_STATUS = 0X41;
const auto OBD_PID_CONTROL_MODULE_VOLTAGE = 0X42;
const auto OBD_PID_ABSOLUTE_LOAD_VALUE = 0X43;
const auto OBD_PID_FUEL_AIR_COMMANDED_EQUIV_RATIO = 0X44;
const auto OBD_PID_RELATIVE_THROTTLE = 0X45;
const auto OBD_PID_AMBIENT_AIR_TEMPERATURE = 0X46;
const auto OBD_PID_ABSOLUTE_THROTTLE_B = 0X47;
const auto OBD_PID_ACCELERATOR_PEDAL_POSITION_D = 0X49;
const auto OBD_PID_ACCELERATOR_PEDAL_POSITION_E = 0X4a;
const auto OBD_PID_COMMANDED_THROTTLE_ACTUATOR = 0X4c;
const size_t NUM_PIDS_TO_REQUEST = 30;
const uint8_t pidsToRequest[NUM_PIDS_TO_REQUEST] = {
OBD_PID_ENGINE_LOAD,
OBD_PID_COOLANT_TEMPERATURE,
OBD_PID_SHORT_TERM_FUEL_TRIM,
OBD_PID_LONG_TERM_FUEL_TRIM,
OBD_PID_ENGINE_RPM,
OBD_PID_VEHICLE_SPEED,
OBD_PID_TIMING_ADVANCE,
OBD_PID_INTAKE_AIR_TEMPERATURE,
OBD_PID_MAF_AIR_FLOW_RATE,
OBD_PID_THROTTLE,
OBD_PID_O2_SENSOR_2,
OBD_PID_ENGINE_RUN_TIME,
OBD_PID_DISTANCE_TRAVELED_WITH_MIL_ON,
OBD_PID_COMMANDED_EVAPORATIVE_PURGE,
OBD_PID_FUEL_TANK_LEVEL_INPUT,
OBD_PID_WARM_UPS_SINCE_CODES_CLEARED,
OBD_PID_DISTANCE_TRAVELED_SINCE_CODES_CLEARED,
OBD_PID_ABSOLUTE_BAROMETRIC_PRESSURE,
OBD_PID_O2_SENSOR_1,
OBD_PID_CATALYST_TEMPERATURE_BANK1_SENSOR1,
OBD_PID_MONITOR_STATUS,
OBD_PID_CONTROL_MODULE_VOLTAGE,
OBD_PID_ABSOLUTE_LOAD_VALUE,
OBD_PID_FUEL_AIR_COMMANDED_EQUIV_RATIO,
OBD_PID_RELATIVE_THROTTLE,
OBD_PID_AMBIENT_AIR_TEMPERATURE,
OBD_PID_ABSOLUTE_THROTTLE_B,
OBD_PID_ACCELERATOR_PEDAL_POSITION_D,
OBD_PID_ACCELERATOR_PEDAL_POSITION_E,
OBD_PID_COMMANDED_THROTTLE_ACTUATOR
};
uint8_t pidIndex = NUM_PIDS_TO_REQUEST - 1;
String dumpForPublish;
auto *obdLoopFunction = sendObdRequest;
unsigned long transitionTime = 0;
uint8_t lastMessageData[8];
void setup() {
Serial.begin(115200);
carloop.begin();
Particle.connect();
transitionTime = millis();
}
void loop() {
carloop.update();
printValuesAtInterval();
obdLoopFunction();
}
/*************** Begin: OBD Loop Functions ****************/
void sendObdRequest() {
pidIndex = (pidIndex + 1) % NUM_PIDS_TO_REQUEST;
CANMessage message;
message.id = OBD_CAN_BROADCAST_ID;
message.len = 8; // just always use 8
message.data[0] = 0x02; // 0 = single-frame format, 2 = num data bytes
message.data[1] = OBD_MODE_CURRENT_DATA; // OBD MODE
message.data[2] = pidsToRequest[pidIndex]; // OBD PID
carloop.can().transmit(message);
obdLoopFunction = waitForObdResponse;
transitionTime = millis();
}
void waitForObdResponse() {
if (millis() - transitionTime >= 100) {
obdLoopFunction = delayUntilNextRequest;
transitionTime = millis();
return;
}
String dump;
CANMessage message;
while (carloop.can().receive(message)) {
canMessageCount++;
if (message.id == 0x130) {
// This message gets sent every tenth of a second,
// so only publish it when the value changes.
if (!byteArray8Equal(message.data, lastMessageData)) {
memcpy(lastMessageData, message.data, 8);
dump += dumpMessage(message);
}
} else {
dump += dumpMessage(message);
}
}
Serial.write(dump);
dumpForPublish += dump;
// change to:
// if > 196 binary bytes
// when each time stamp is exactly 2 bytes encoding integer tenths of a second
// and 1-5 data bytes follow
// then we base85 encode the binary to get close to the 255-byte publish limit
if (dumpForPublish.length() >= 220) {
Particle.publish("m", dumpForPublish, 60, PRIVATE);
dumpForPublish.remove(0);
}
}
void delayUntilNextRequest() {
if (millis() - transitionTime >= 80) {
obdLoopFunction = sendObdRequest;
transitionTime = millis();
}
}
/*************** End: OBD Loop Functions ****************/
void printValuesAtInterval() {
static const unsigned long interval = 20000;
static unsigned long lastDisplay = 0;
if (millis() - lastDisplay < interval) {
return;
}
lastDisplay = millis();
printValues();
}
void printValues() {
Serial.printf("Battery voltage: %12f ", carloop.battery());
Serial.printf(“CAN messages: %12d “, canMessageCount);
Serial.println(””);
}
String dumpMessage(const CANMessage &message) {
// change to: each timestamp as exactly 2 bytes
// as unsigned integer tenths of a second
// wrap around carefully
// maybe (quick stab) – uint16_t t = (millis() / 100) & 0xffff
String str = String::format(“%.1f:”, millis() / 1000.0);
int startIdx = 0;
int lastIdx = message.len - 1;
if (message.id >= 0x700) {
// We can ignore the first two bytes
// data[0] is the length
// data[1] is the UDS service response ID, always 0x41 for me
// data[2] is important to include - it’s the PID
startIdx = 2;
if (message.data[0] < message.len) {
lastIdx = message.data[0];
}
}
// hmm… Since the binary data can include zeros
// I may have to do the base85 encoding on the fly
// rather than right before publish…
for (int i = startIdx; i <= lastIdx; i++) {
str += String::format(“%02x”, message.data[i]);
}
str += “,”;
return str;
}
bool byteArray8Equal(uint8_t a1[8], uint8_t a2[8]) {
for (int i = 0; i < 8; i++) {
if (a1[i] != a2[i]) return false;
}
return true;
}
Awesome.