LilyGo T-A7670SA LTE GPS Tracker

Before uploading the code, edit the substitutions to meet your requirements.

If you have trouble adding schedules initially after first install, remove all the schedules before adding new ones.

remove_schedule_1
remove_schedule_2
remove_schedule_2

now add the new schedules

new_schedule_1 monday,tuesday,friday arm 23:00 disarm 07:00

Connect to your access point and login to the Web UI at http://192.168.4.1. Check the “sms_sender” to check the exact format that the phone number was received as and update your phone_number_x accordingly. The number will usually include your country code, e.g., +611234567

Yes, just leave the phone_number_2 and phone_number_3 values blank (initial_value: ‘””‘). You can also use the remove_number_2 and remove_number_3, this will blank out the values for phone numbers 2 and 3.

Arm the alarm (arm) and then turn the Fuel Shutoff relay off (relay_off) and drive the car over 5km/h. The Speed alarm should now activate and send a notification to phone_number_1, phone_number_2, and phone_number_3.

Constant reboots can be caused by multiple issues, mostly due to esphome failing to connect to the API server or Wi-Fi failing to connect to the network. If you are using the Wi-Fi component in esphome (not the access point), ensure you have added the reboot_timeout: 0s to your config. This is especially important for the api: section.

api:
  encryption:
    key: ""
  reboot_timeout: 0s

Sometimes, the SIM800L can continue to process the same SMS upon boot. This is coded to prevent this, but if for some reason the SIM800L keeps processing the reboot SMS on every boot, try to force it out of the reboot cycle by sending another message, any message will do.

You could also quickly connect to the device webpage and turn off the SIM800L using the SIM800L_PWR switch in the web interface, this will allow you to reflash via OTA as the SIM800L will not process any SMS message when powered down.

To test the fuel relay, you can login to the Web UI using the access point at http://192.168.4.1 and arm the alarm (arm), you should see the Fuel Shutoff switch turn on in the Web UI.

To test your ignition, again login to the Web UI and turn on your ignition, you should see the Ignition sensor state change to “on”.

Further test to check for GPS lock can be done using the Web UI, or using the status command (status) to confirm if there is a GPS lock and how many satellites.

To test the Speed alarm, arm the alarm (arm) and turn off the fuel shutoff relay (relay_off) and drive the car over 5km/s. All phone numbers should now receive a notification Car speed alarm activated. Car is travelling more than 5km/h.

It should not. I have made it so that it will try to interpret abbreviated days of the week, such as mon, tue, tues, wed thu, thurs etc.

However, it is best to just use the full name, monday,tuesday,wednesday etc.

This may be as a result of GPS drift. If this is an issue, increase the speed in the interval: section for the speed alarm.

10.0 && !id(speed_alarm_triggered))

This is factory set for most vehicles. The default behavior is to relock the doors if unlocked and a door is not opened. To get around this, you can wire the door circuit through another relay and take it to GND. This will trick the car into thinking the door has been opened, and the doors will not lock automatically.

Set the code on unlock to trigger both the UNLOCK relay and another relay, the relay used for sending a door open signal.

Wire the door open NEGATIVE through a NC contact of the relay. When the unlock relay activates, this will also activate the door open relay, removing the GROUND and sending an open signal to the car.

This will result in the car staying unlocked until re locked.

Ensure the schedule cycles through the start and end time correctly. For example, if you set a schedule for

new_schedule_1 monday arm 14:00 disarm 16:00

make sure you add this schedule BEFORE 14:00, not after, otherwise the disarm command will not run as it has not passed the arm cycle of the schedule.

If you want to use without the door open and/or ignition sensors, you have 2 options.

1. Short GPIO21 and GPIO13 to GND with a short piece of wire. This will keep the inputs closed and prevent them from ever opening.
2. Change the binary_sensor to be inverted. This way it will always see the input as “Closed”.

binary_sensor:
  - platform: gpio
    id: doors
    pin:
      number: 21
      mode: INPUT_PULLUP
      inverted: true
    name: "Doors"

• One thing I thought of was how to wire the Fuel Shutoff Relay. I my case I went for Normally Closed as the relay I had only had a Normally Closed contact, thus when the relay is powered down, the relay is closed circuit allowing the fuel pump to operate. If the device is removed or powered down, this relay will de-energize and allow the fuel pump to operate again. You could wire the relay as Normally Open, this way power is required to energize the relay for the car to be able to start. This is a more secure option.
• For the remainder of the relay wiring, it is up to you if you want to switch positive or negative, for me I am switching negative for everything as per my wiring diagrams.

For safety reasons, the fuel shutoff relay will not activate when the ignition is ON. This is because all ARM commands are blocked by a gate attached to the IGNITION binary_sensor, thus the alarm will fail to ARM when the ignition is ON.

You can however manually activate the full shutoff relay ANYTIME with the relay_on command.

You can change the horn alarm activation time and the number of times the horn activates for the “find” command below. The default values are 2.5 minutes for alarm activation and 3 fast pulses at 200ms for the find horn highlighted in bold below.

  - interval: 1s
    id: alarm_pulse
    then:
      - lambda: |-
          if (id(alarm_siren_switch).state) {
            if (id(gps_time).now().is_valid()) {
              int elapsed = id(gps_time).now().timestamp - id(alarm_start_time);
              if (elapsed >= 150) {
                ESP_LOGD("alarm", "Alarm siren timed out after 2.5 minutes.");
                id(alarm_siren_switch).turn_off();
                id(alarm_triggered) = false;
                return;
              }
            }
            id(horn_output).turn_on();
            delay(500);
            id(horn_output).turn_off();
          }

  - interval: 200ms
    id: find_pulse
    then:
      - lambda: |-
          static int find_count = 0;

          if (id(find_switch).state) {
            if (find_count < 3) {
              id(horn_output).turn_on();
              delay(200);
              id(horn_output).turn_off();
              find_count++;
            } else {
              id(find_switch).turn_off();
              find_count = 0;
            }
          } else {
            find_count = 0;
          }

You can change the default values of functions such as horn_feedback and door_alerts to be enabled on boot or firmware updates. This value should be persistent across reboots and therefor will stay in the last state set (horn_feedback_on or door_alerts_on) but if you want to set it statically, change the following in your globals section:

• GPS Speed Alarm
  Arm the alarm (arm), disable the fuel shutoff relay (relay_off) and drive the car over 10km/h. You should receive a notification Car speed alarm activated. Car is travelling more than 10km/h.
• Phone Number and Schedule Persistency
  Add a new phone number (new_number_1) and add a new schedule (new_schedule_1), flash the firmware again and then query the stored values (phone_number_1 and schedule_1) they should now return the previous set values.
• Fuel Shutoff Safety
  Turn on the ignition, attempt to arm the alarm (arm). You can also arm the alarm manually in the web UI. The alarm should not turn the fuel shutoff relay ON when the ignition state if ON. Also add a schedule and have it cycle the arm time when the ignition is ON (new_schedule_x). It is important to note that the fuel shutoff relay can be activated at any time including with the ignition ON sending relay on.
• GY521 Level Alarm
  Set your desired tilt angle in the Web UI. Park the car on a slope and arm the alarm. Release the handbrake and roll the car down the slow to a level angle or a angle that exceeds your set tilt angle. The alarm should activate.

By default, logging is disabled for most components due to the massive amounts of noise and increased CPU load. It is recommended to leave logging disabled and only enable logging for troubleshooting.

Logging options for each component can be set as per below. The available values are INFO, WARN, DEBUG, VERY_VERBOSE. Do not change the top level logger level from VERY_VERBOSE, just change the individual components below.

The I2C devices are installed on the board in the following order. They can be soldered hard up to the PCB or stepped off using header pins.

Ensure that GPS is powered on with AT+CGNSSPWR=1.
Query the GPS location using AT+CGPSINFO, you should receive a response like

AT+CGPSINFO +CGPSINFO: xxxx.xxxxx7,S,1xxx.xxxxxx,E,201025,194828.00,xx4,0.000,6.08 OK

If there is no valid GPS out, try using a different Antennas as the stock antenna can be known to be bad.

Sometimes, a toggle of the GPS power can also resolve GPS issues,
AT+CGNSSPWR=0
AT+CGNSSPWR=1
Then check again with AT+CGNSSINFO

As of the latest release, time is not queried using GPS anymore, the time source is the Network Operator, using the SNTP platform. Time can be queried using AT+CCLK. See the section below.

If longer messages are cut off, try the following. This enables features like concatenated SMS / UDHI handling allowing for multiple messages to be queued and sent by the modem.

AT+CMGF=1
AT+CSCS=”GSM”
AT+CSMS=1
AT+CSMP=17,167,0,0
AT+CMMS=2
AT&W

Time is synced directly over LTE from the network. Time will only sync when the device shows as Registered on the network. AT+CCLK? queries the network time and updates the system clock. This is only required on a full power loss.

AT+CTZU=1 – enables automatic time and time-zone update from the network
AT+CTZR=1 – turns on unsolicited time-zone change reporting
AT+CCLK? – Queries the network for the current time. Returns “yy/MM/dd,hh:mm:ss”

You can also manually set the time using the following command and format. Note that this will not persist across reboots.

AT+CCLK=”yy/MM/dd,hh:mm:ss±zz”

This will update the global system time: with ID gps_time, which is the main time provider for all functions in the code.

If you can receive SMS but cannot send, check you have enough DATA to send the SMS.

This is almost always a BAUD mismatch. Try change your BAUD rate in UART: block until SMS messages start working. You should see outputs in the LOG like [modem:2094] AT Response: OK. If there are no [modem:2094] messages, communication with the A7670 is failing.

uart:
  - id: modem_uart
    baud_rate: 115200 <<------ Switch to 9600
    tx_pin: 26
    rx_pin: 27
    rx_buffer_size: 2048

You can manually set and save the BAUD rate on the A7670 with the following AT commands

AT
AT+IPR=115200 <<------ New BAUD rate
AT&W <<------ Save to NVRAM
AT+CFUN=1,1 <<------ Check the current BAUD rate