AutoPi TMU CM4

The AutoPi TMU CM4 is an open-platform vehicle telematics unit built on the Raspberry Pi Compute Module 4, combining automotive-grade OBD-II and dual CAN bus interfaces with 4G LTE cellular connectivity, GPS/GNSS positioning, WiFi, and Bluetooth in a single OBD-II dongle form factor. The quad-core ARM processor runs a full Linux environment, enabling edge computing workloads — data filtering, anomaly detection, and local analytics — directly in the vehicle before transmitting to the cloud.

Technical Specifications

Feature	Specification
Processor	Broadcom BCM2711 Cortex-A72 quad-core @ 1.5 GHz
Memory	1 GB LPDDR4 (upgradeable to 2/4/8 GB)
Storage	8 GB eMMC (upgradeable to 16/32 GB)
CAN Interface	2x CAN-FD via SocketCAN
OBD-II	Standard PID polling + custom protocols
DoIP/UDS	Available via DoIP HAT accessory
Cellular	4G LTE Cat 4 (3G/EDGE fallback)
Wi-Fi	2.4 GHz + 5 GHz 802.11ac
Bluetooth	5.0 + BLE
GNSS	GPS/GLONASS/BeiDou/Galileo/QZSS with A-GPS
IMU	3-axis accelerometer + 3-axis gyroscope
Sampling Rate	100 samples/sec (microsecond timestamps)
Data Storage	Weeks of on-device logging, compression before upload
Expansion	40-pin HAT header, 2x USB, Gigabit Ethernet, micro HDMI
Audio	Built-in speaker
Power Input	12.5–35 V DC, Smart Power Manager (SPM)
Security	Integrated security IC for protected keys
Operating Temp	-20°C to +70°C
Dimensions	133.5 × 68.2 × 36.6 mm, 170 g
Certifications	CE, FCC
OS	Raspbian with AutoPi Core
Edge Computing	Docker, Python, Node.js, SocketCAN
Cloud	AutoPi Cloud (OTA, fleet management, workflows)

The AutoPi Cloud platform provides fleet management, remote device configuration, over-the-air updates, and a visual workflow builder for creating custom data logging and alerting rules without writing code. For developers, the open Linux environment supports Python, Node.js, and custom services, with direct CAN bus access for raw frame capture and injection. Applications span fleet telematics and driver behavior monitoring, connected car prototyping, CAN bus reverse engineering and data logging, and remote vehicle diagnostics for aftermarket and R&D teams.

The open-platform approach distinguishes the AutoPi TMU CM4 from closed telematics units that limit users to predefined data points and cloud dashboards. Engineers and fleet operators can access raw CAN bus frames, build custom data pipelines, deploy edge analytics, and integrate with third-party systems — capabilities that are essential for vehicle R&D, aftermarket diagnostics development, and specialized fleet applications. GSAS Micro Systems provides the AutoPi TMU CM4 with guidance on CAN bus integration, edge computing application development, and AutoPi Cloud configuration for fleet telematics and vehicle development teams across India.