Micare GPS Tracker

2022

Micare PS, the vehicle-search company behind micare-ps.com, asked us to build a tracking device of their own instead of reselling third-party GPS chips. We already ran their platform, first built on Drupal and rewritten by us on Laravel, so the tracker got its own backend on NestJS next to it. The result is one product line covering the device, the network, and the apps: a custom hardware tracker, the firmware that runs on it, a mobile app for owners, and a web dashboard for fleet operators.

The Challenge

Off-the-shelf trackers gave Micare PS no control over battery life, reporting accuracy, or the update cycle. A customer with 350 classic cars needed devices that stayed connected across four weeks in another country without dropping out. That meant designing hardware, not just an app around someone else’s board.

The device had to run for months on battery, hold its position through GPS dead zones, arm and disarm like an alarm system, and report over cellular networks that vary by country. Every one of those constraints pushed back on the others: better GPS accuracy meant more power draw; more frequent reporting meant a shorter battery life; and each firmware revision had to survive real theft and towing scenarios, not just bench tests.

What We Built

Hardware

Custom PCB design, iterated across multiple board revisions
GPS module swapped from an early chip to the LC86G, with a new GPS antenna; we also bench-tested the GPS built into the SIM7080G
Cellular modem migrated from SIM800C to SIM7080G for LTE; we prototyped the SIM7020C as an alternative and compared power draw in MQTT mode
Storage moved from EEPROM to FRAM to fix write-cycle wear and data loss on power cuts
Real-time clock circuit for time sync and scheduled wake from sleep
Enclosure and internal layout redesigned for factory assembly

Firmware

Power management tuned through direct battery-consumption measurement, cutting draw during sleep and idle GPS search
Cell-based location (LBS) as a fallback when GPS can’t get a fix
MQTT connection to our own broker and NestJS API, with message format switched from JSON to MessagePack to cut payload size. A Thingsboard MQTT integration served only as an early prototype
Watchdog and EEPROM/FRAM cleanup logic to recover devices stuck in a bad state
NFC-based device pairing, alongside SIM management through EMnify

Mobile app (iOS and Android)

Google and email authentication, with password recovery
Live map view showing device position and history
Armed/disarmed states, with push notifications on state change and on movement
SOS button and alarm triggers
German- and Spanish-language builds for international customers

Web dashboard

Admin views for managing trackers, users, and devices
Per-device detail pages with position history and filters
Role-based access separating fleet admins from individual owners

Delivery

Firmware went through several full hardware iterations: a new GPS module and a new cellular modem, each one driven by field reports from real customers, including the classic-car fleet whose devices lost connection abroad. That case narrowed the firmware down to specific watchdog resets and EEPROM overflow bugs, fixes that then shipped to every device in the field. The mobile app and dashboard were built alongside the hardware, so each firmware change already had a UI ready to surface it in the same release.

Engineering at a glance

Hardware track: April 2022 to November 2024, at least 2,563 engineering hours from 3 hardware engineers.
Firmware: RTC synchronised from the GPS fix. Deep sleep with wake-up on an accelerometer (ADXL) interrupt or an RTC alarm.
Reporting over MQTT through an ACL-protected broker, with a USSD/SMS fallback.
Hardware generations from 2G to 4G, then a factory assembly stage and MQTT security work in 2024.
Backend “tracking API” (NestJS, PostgreSQL, Firebase, Mosquitto MQTT broker with ACL): 523 commits, 77 semver releases up to 1.24.0, with backup and restore scripts.
NFC mobile app (React Native plus Kotlin), releases 1.0.0 and 1.1.0. Low-power design carried over from our earlier GAT line: STM32 with SIM808, and GSM sleep before the GPS fix.