Upgrade Homematic with a Pi 4 as Your New Hub

Building a Homematic Smart-Home Hub on Raspberry Pi 4

A Homematic system by eQ3 can handle everything from automatically closing skylights when it rains to optimising heating and providing security via window and door sensors. If you find your current Homematic base station (like the CCU3) is underpowered—particularly if you want to run extra plug-ins such as RedMatic (Node-RED) for enhanced automation or dashboards—you can replace it with a more powerful Raspberry Pi 4 (or Pi 5) running the open-source RaspberryMatic platform. This guide walks you through the process.

Why Switch to a Pi?

Performance Limitations of CCU3

The CCU3 is a homematic base station that internally uses a Raspberry Pi 3 B and an integrated radio board. It can become sluggish if your installation grows large—e.g., hundreds of sensors and actuators. Adding extra software such as RedMatic or custom dashboards may further slow it down.

Keeping Legacy Devices

Newer eQ3 hubs like the “Homematic IP Home Control Unit” only support the current Homematic IP radio protocol. They can’t manage older devices using the classic BidCOS protocol. By using a Pi, you can continue using all your legacy Homematic (non-IP) devices alongside modern Homematic IP components.

Local Operation

RaspberryMatic is the open-source version of eQ3’s official central software (via the Homematic Open Central Control Unit SDK). It runs fully offline on your Pi—no cloud needed. The system remains compatible with the official Homematic app and hardware.

Equipment Overview

Time Required
3 to 4 hours for assembly and configuration

Approximate Cost
€100–150, depending on the chosen Pi model, cooling, and enclosure

Key Components

• Raspberry Pi 4 (recommendation: 8 GB RAM to ensure plenty of headroom)
• Heat sink (such as the Geekworm P165-B) or active cooler for the Pi
• Homematic radio module (RPI-RF-MOD is common; must support both BidCOS and Homematic IP if you need backward compatibility)
• microSD Card (≥32 GB recommended; e.g., a 128 GB SanDisk Extreme A2)
• Enclosure (3D-printed or an off-the-shelf case that fits your Pi plus the attached radio module)
• Power Supply (e.g. from the CCU3 or a standard Pi USB-C PSU)

Optionally, you may need:

• A pigtail and external 868 MHz antenna to reduce radio interference.
• A grounded heat sink to mitigate RF noise on the Pi 4’s board.

Step 1: Review Current Setup and Backup

Before you switch to RaspberryMatic:

1. Upgrade your existing CCU3 (or other Homematic hub) to a matching firmware version—RaspberryMatic must run the same version for a seamless backup restore.
2. Create a backup from Settings → System Control → Security → Create backup in the CCU’s web interface. This produces a .sbk file containing all devices, logic, and configurations.

Power down the old hub (CCU3) once you have the backup.

Step 2: Flash RaspberryMatic onto a MicroSD

1. Download RaspberryMatic for the Pi 4 from the official project site.
2. Use Raspberry Pi Imager to burn the image onto your microSD card:
   • Under Choose OS, go to Other specific-purpose OS → Home assistants and home automation → RaspberryMatic (Pi4).
   • Select your microSD card.
   • Click “Write.”

Once done, insert the microSD into your Pi 4.

Step 3: Prepare the Pi and Radio Module

1. Assemble the Pi
   • If using the RPI-RF-MOD board from a CCU3, you may need a 40-pin GPIO extension to account for differences in the Pi 4 layout.
   • Mount any cooling solution. For a fanless approach, attach the Geekworm P165-B heat sink (or similar) with thermal paste or pads.
2. Install/Connect the Radio Board
   • The RPI-RF-MOD typically sits on top of the 40-pin GPIO. Ensure the 5 V supply line is correctly aligned.
   • If you kept the old CCU3 PSU, it can power both the radio board and the Pi via the radio board’s barrel jack. Or use a standard Pi USB-C PSU.

Possible Radio Interference Issue
The Pi 4’s USB 3.0 and overall design may cause interference on the 868 MHz Homematic frequency. To reduce the “Carrier Sense” occupancy to near zero (and avoid missing signals):

• Ground the Pi 4’s metal heat sink to 0 V (Pi ground).
• Replace the radio board’s tiny on-board antenna with a pigtail SMA connector and use an external 868 MHz antenna placed away from the Pi.

Step 4: First Boot and Restore

1. Power On the Pi with RaspberryMatic.
2. Wait a minute or two, then open your browser to either the Pi’s IP address or http://homematic-raspi/.
3. If asked to set a password, do so. Then go to Settings → System Control → Security → Restore backup and select the .sbk file from the old CCU3.
4. Reboot the Pi. After it restarts, all your devices and automations should appear as they were before.

Step 5: Addressing Radio Noise

• Check the “Duty Cycle” and “Carrier Sense” values in Settings → System Control → System Overview. If the “Carrier Sense” is high (50%+), it indicates radio interference.
• Solution: Use an external antenna with enough distance from the Pi’s board. Ensure your heat sink is grounded. This typically brings the carrier sense down to near zero, restoring reliable communication.

(Optional) Step 6: 3D-Printed Enclosure

Because the Pi plus radio module may not fit standard cases, many enthusiasts design or print custom enclosures. For example:

• A 3D-printed case with ample airflow.
• Mounting points for external antenna connections.

Pros and Cons of Alternative Modules

If you don’t have an RPI-RF-MOD, other modules exist (like HM-MOD-RPI-PCB or the USB stick HmIP-RFUSB), but check:

• Protocol Support: Some modules only handle either BidCOS (classic Homematic) or Homematic IP.
• Wired Support: If you need Homematic wired or Homematic IP wired, you may need additional hardware.

Step 7: Enjoy a Stronger Homematic Base

Your new Pi-based RaspberryMatic hub should perform significantly faster than a CCU3. You can install plug-ins like RedMatic for advanced automation logic or Node-RED flows. You’ll gain:

• Local and offline operation (no cloud dependencies).
• Backwards compatibility with all your older Homematic devices as well as Homematic IP.
• Flexibility to keep adding sensors, scripts, or expansions.

Why Homematic?
Some users choose Homematic for its offline capability, robust bidirectional protocol, and wide range of devices. The system also supports direct communication between sensors and actuators (without the controller in the loop), beneficial if the hub is offline during critical events (like a window sensor shutting off a radiator).