Using RTL-SDR and rtl_433 for Water Meter Home Assistant Integration

After reading success stories online, I picked up the Nooelec RTL-SDR v5 Bundle from Amazon. This little USB SDR dongle can tune from 100kHz to 1.75GHz, which is perfect for picking up utility meter signals.

My first attempt was to plug the SDR into my Raspberry Pi 4 running Home Assistant and use the rtl_433 addon. Unfortunately, I ran into some power issues and weird addon errors, likely due to the antenna drawing too much power with everything else I already had plugged in.

Setting Up a Dedicated SDR Host for Home Assistant

To fix this, I decided to run the SDR on a dedicated Raspberry Pi. I had an old, original Pi 1 Model B lying around. With a decent 2A power supply and a wireless N dongle for network connectivity, I installed Raspbian Lite and the rtl_433 tool.

I experimented with both 433 MHz and 915 MHz frequencies, using the coiled antennas included in the kit. The 900 MHz antenna ended up being the winner. On the 915 MHz band, I finally started seeing data in the logs:

Identifying My Water Meter in Home Assistant Logs

One key data point stood out: a field called Consumption Data showing a value around 168000. After comparing this with the value on my actual Neptune T-10 water meter (used by the City of Ottawa), I realized I was picking up my own water meter’s signal!

I also saw signals from neighboring meters, but by monitoring the data for a few hours, I confirmed which one was mine. The value updated every 15 to 30 minutes.

Fixing USB Stability for Water Meter Data Collection

One hiccup: after several hours, rtl_433 would crash with libusb errors. Unplugging and replugging fixed it temporarily, but the long-term solution was to use a powered USB hub (4A supply) to give the SDR the juice it needed. I also ditched the USB extension cable from the kit and plugged the SDR directly into the hub. That seemed to fix the issue.

The nice thing with this hub is also that I can use it to power the Pi; so I have 1 power cable for the hub, with 1 USB cable running from the hub to the Pi. I have a microUSB cable going from the hub to the Pi for power, and I have the RTL-SDR and Wi-Fi dongle plugged into the USB hub. You can see the final setup up close in the picture below:

Publishing Water Meter Data to Home Assistant via MQTT

With the setup stable, I configured rtl_433 to output data to MQTT. Since I already had the Mosquitto addon running in Home Assistant, I pointed rtl_433 to it and monitored the output using MQTT Explorer. I found the data for my meter which matched up to the logs I was seeing directly on the Pi:

Creating a Systemd Service for Water Meter Integration

To make everything persistent, I created a systemd service at /etc/systemd/system/ha-sdr-915M.service:

[Unit]
Description=rtl_433 on 915M SDR
After=network.target

[Service]
ExecStart=/usr/local/bin/ha-sdr-915M.sh
Restart=unless-stopped
WorkingDirectory=/usr/local/bin

[Install]
WantedBy=multi-user.target

The script at /usr/local/bin/ha-sdr-915M.sh:

#!/bin/bash

source /etc/ha-sdr.env

LOGFILE="/var/log/ha-sdr/ha-sdr-915M.log"

/usr/bin/rtl_433 -f 915M -F mqtt://homeassistant.domain.com:1883,user=$MQTT_USER,pass=$MQTT_PASS -F kv 2>&1 | while IFS= read -r line
do
    echo "$(date '+%Y-%m-%d %H:%M:%S') $line"
done >> "$LOGFILE"

I enabled the service by running systemctl daemon-reload and systemctl enable ha-sdr-915M.service.

Adding a Water Meter MQTT Sensor in Home Assistant

In Home Assistant YAML configuration:

sensor:
  - name: "Water Meter Consumption Data"
    object_id: water_meter_consumption_data
    state_topic: "rtl_433/pisdrfrontoh/devices/ERT-SCM/33391039/consumption_data"
    unit_of_measurement: "gal"
    state_class: total_increasing
    device_class: water

I noticed the values from my meter were in gallons, even though I’m in Canada where cubic meters or litres are common. To convert to litres, I added a template sensor:

sensor:
  - name: "Water Meter Consumption (Litres)"
    state: >
      {{ states('sensor.water_meter_consumption_data') | float * 3.78541178 | round(2) }}
    unit_of_measurement: "L"
    device_class: water

Setting Up a Utility Meter for Daily Water Tracking

Finally, I created a utility meter entity to track daily water usage:

utility_meter:
  daily_water:
    source: sensor.water_meter_consumption_litres
    cycle: daily

This entity allowed me to graph and display daily water usage data directly from my water meter in Home Assistant:

Final Thoughts on Monitoring My Water Meter with Home Assistant

This project took a few days of tuning and monitoring, but I’m thrilled with the results. For now, I’m only picking up water meter data, but I’m hopeful I’ll find more signals soon.

If you’re thinking about tracking your water meter in Home Assistant, using an SDR like the Nooelec RTL-SDR v5 and rtl_433 software is a great DIY approach. The insight into water usage is already super useful!

The post Reading my Water Meter in Home Assistant with USB SDR appeared first on TechOpt.

Steps to Set Custom Icons in Zigbee2MQTT Home Assistant Add-On

1. Open Your Home Assistant Configuration Folder

You’ll need to access the zigbee2mqtt folder in your Home Assistant config directory. I use the Studio Code Server add-on to do this, but you can use any method you prefer.

• If using Studio Code Server, navigate to config/zigbee2mqtt/.

2. Create the device_icons Folder

If the device_icons folder doesn’t already exist inside the zigbee2mqtt directory, create it.

• In Studio Code Server, right-click inside the zigbee2mqtt folder and select New Folder.
• Name the folder device_icons.

3. Add Your Custom Icon

For best results, your icon should be:

• A PNG file
• 512×512 pixels
• Have a transparent background

To add it:

• Drag and drop the PNG file into the device_icons folder using the Studio Code Server file browser.
• Alternatively, upload the file using an SCP tool or any other method that works for you.

For my IKEA E2204 smart plug, I named my file:

ikea-tretakt-smart-plug.png

4. Assign the Icon in Zigbee2MQTT

Now that the icon is in place, it’s time to assign it to your device in Zigbee2MQTT.

1. Open Zigbee2MQTT in Home Assistant.
2. Find your device in the Devices list and click on its name.
3. Go to the Settings tab.
4. Scroll all the way down to the Icon box.
5. Enter the relative path of your icon, e.g.:device_icons/ikea-tretakt-smart-plug.png
6. Click Submit.

5. Verify Your New Icon

Once you’ve assigned the custom icon:

• Go back to the Devices page in Zigbee2MQTT.
• Your new icon should now appear next to the device name!

Final Thoughts

Using custom icons in Zigbee2MQTT in Home Assistant is a great way to make your smart home setup more intuitive and visually appealing. Whether you’re correcting an incorrect default icon or just want a personalized look, this method is quick and easy!

The post Set Custom Device Icons in Zigbee2MQTT in Home Assistant appeared first on TechOpt.

Each of these brands has its strengths and weaknesses, making them better suited for different users.

1. Meross Bulbs

Pros:

• Affordable and widely available on Amazon
• Compatible with HomeKit, Alexa, and Google Assistant

Cons:

• Frequent Wi-Fi disconnection issues, even on the latest firmware
• Unreliable performance on some networks

I personally tried Meross smart bulbs, but they constantly disconnected from my Wi-Fi and wouldn’t respond properly. This seems to be a known issue with Meross bulbs and certain Wi-Fi networks, making them difficult to recommend despite their affordability.

I would not buy Meross bulbs again at all.

2. Sengled Bulbs

Pros:

• Available at major retailers and online
• Zigbee and Wi-Fi options available

Cons:

• Wi-Fi bulbs develop color issues and flickering over time
• Zigbee bulbs do not act as repeaters despite being powered devices

I had a few Sengled bulbs over the years. My Sengled Wi-Fi bulbs initially worked great but later started flickering and having color inconsistencies.

Their Zigbee bulbs also don’t function as repeaters, which is a downside if you’re looking to strengthen your Zigbee mesh network.

Sengled bulbs are nice if you want a cheap option, but they don’t seem to have the longest lifespan in my experience.

3. TP-Link Kasa Bulbs

Pros:

• Reliable brand with good integration into smart home ecosystems
• Competitive pricing and available on Amazon
• Has great reviews overall

Cons:

• Recent firmware updates breaking third-party API access
• Potential issues with Home Assistant and other platforms

While I haven’t personally used Kasa’s smart bulbs, I have had experience with their Wi-Fi smart plugs, which were very reliable. I actually swore by TP-Link Kasa smart plugs for years.

However, TP-Link supposedly recently started pushing updates to some devices that block third-party API access, affecting integrations with Home Assistant and other platforms.

Because of this, I’m avoiding new Kasa devices, and this is a significant downside for smart home enthusiasts.

4. Philips Hue Bulbs (Winner)

Pros:

• Rock-solid reliability with Zigbee technology
• Acts as a Zigbee repeater, strengthening your network
• Excellent color accuracy and brightness
• Can be used with or without the Hue Bridge
• Feature-rich Hue app with dynamic lighting effects

Cons:

• Much more expensive than other options

Philips Hue has been a leader in smart lighting for years, and it continues to be the best choice in 2025. I have never experienced dropouts with Hue bulbs, and they always produce vibrant, accurate colors at a consistent brightness. Since they operate using Zigbee, they strengthen the network by acting as repeaters, unlike Sengled’s Zigbee bulbs.

Additionally, the Hue app provides excellent lighting animations and effects, making it a standout choice.

While they are pricier, the reliability and features make them worth it. I’ve switched all my smart lights to Philips Hue in early 2025.

5. Govee Bulbs

Pros:

• Budget-friendly and well-reviewed on Amazon
• Sold at major retailers
• Offers good color accuracy

Cons:

• Uses Wi-Fi, which can be affected by network conditions

Govee has become a popular budget brand, offering smart bulbs that perform well for the price. They are available both online and in physical stores, making them easy to find. However, like other Wi-Fi-based smart bulbs, they may suffer from connectivity issues depending on your network conditions.

If you’re on a tight budget, they can be a decent option, but they don’t match the reliability of Zigbee-based solutions like Philips Hue.

Conclusion: Philips Hue are Still the Best Smart Bulbs!

When comparing these five brands, Philips Hue still comes out on top in 2025. It offers the most reliable connection, great color reproduction, and strengthens your Zigbee network. While it is more expensive, it’s the best investment for a hassle-free smart lighting experience.

If you’re on a budget, Govee is a solid alternative, while Sengled and Meross have had reliability issues over time. TP-Link Kasa would have been a good choice if not for the recent API limitations.

At the end of the day, choosing the right smart bulb depends on your specific needs, but if reliability and performance are your top priorities, Philips Hue wins in every aspect, by a longshot!

The post Best Smart Bulbs in 2025: A Comprehensive Comparison appeared first on TechOpt.

Understanding Zigbee and Wireless Interference

Zigbee operates in the 2.4 GHz band using channels numbered from 11 to 26. Meanwhile, Wi-Fi networks (802.11b/g/n) also use the 2.4 GHz band, which can create potential interference with Zigbee signals. Other sources of interference include Bluetooth devices, microwaves, and cordless phones.

Here’s a breakdown of how Zigbee and Wi-Fi channels overlap:

• Zigbee Channel 11 (2405 MHz) – Overlaps with Wi-Fi channels 1-3 (high interference potential).
• Zigbee Channel 15 (2425 MHz) – Slightly overlaps with Wi-Fi channels 6-7 (a much better choice).
• Zigbee Channel 20 (2450 MHz) – Slightly overlaps with Wi-Fi channels 9-11 (another good option).
• Zigbee Channel 25 (2475 MHz) – Sits near Wi-Fi channel 13 (a solid choice in some cases, but not all devices support it well).
• Zigbee Channel 26 (2480 MHz) – Least interference but has reduced transmission power in some regions.

To visually see the overlap between Wi-Fi and Zigbee channels, you can consult the graph below:

Recommended Zigbee Channels

Based on interference patterns, the best Zigbee channels to use are:

1. Channel 15 (2425 MHz)

This channel is one of the best choices because it avoids heavy overlap with common Wi-Fi channels like 1, 6, and 11. It provides a stable connection for most Zigbee devices.

2. Channel 20 (2450 MHz)

Another great option, channel 20, minimizes interference while maintaining strong signal strength. If you experience issues with channel 15, this is a great alternative.

3. Channel 25 (2475 MHz) – With Caution

Channel 25 can work well in environments where interference is a problem, as it avoids most of the congestion. However, some Zigbee devices may not fully support this channel, leading to inconsistent performance.

You should test each device individually with Channel 25 and make sure that you aren’t experiencing any issues. If everything seems okay, channel 25 should work for you.

Zigbee Channel 11: Why You Should Avoid It

Zigbee channel 11 is the default for many devices, but it overlaps heavily with Wi-Fi channels 1, 2, and 3. If you leave your Zigbee network on channel 11 in a busy environment, you may experience dropped connections and slow response times.

Remarks

• Best Channels: Zigbee channel 15 and 20 provide the best balance of performance and minimal interference.
• Channel 25 Consideration: If your devices support it, channel 25 can work well in certain environments but may not be compatible with all devices. Test your devices for compatibility.
• Avoid Channel 11: Due to its heavy overlap with Wi-Fi, channel 11 is not recommended unless necessary.
• Check Your Network: Use tools like Zigbee2MQTT or Home Assistant’s network map to analyze and optimize your Zigbee network.
• Interference Sources: Besides Wi-Fi, other wireless signals such as Bluetooth, microwaves, and cordless phones can also impact Zigbee performance.
• Multiple Zigbee Networks: If you have more than one Zigbee network, use different channels to avoid interference. For example, I have my Philips Hue on channel 15 and my Home Assistant Zigbee2MQTT network on channel 20.
• Wi-Fi Channel 13: Depending on your region, Wi-Fi channel 13 may not be a concern. In Europe and most parts of Asia, channel 13 is allowed and commonly used, whereas in North America, its use is restricted. This means that interference from Wi-Fi channel 13 may not be an issue depending on where you live.

The post Best Zigbee Channel to Use: Avoiding Interference appeared first on TechOpt.

What Is ZHA?

ZHA (Zigbee Home Automation) is the native Zigbee integration for Home Assistant.

Pros of ZHA

• Built-in Integration: Comes pre-installed in Home Assistant, making setup quick and easy.
• Native User Interface: Devices are configured and controlled directly through the Home Assistant UI.
• Reliable Local Control: No need for additional software or external MQTT brokers.
• Minimal Maintenance: Works well for most users without extensive configuration.

Cons of ZHA

• Limited Device Support: Compared to Zigbee2MQTT, some exotic or newly released devices may not be fully supported. However, this is much less of an issue in 2025.
• Fewer Advanced Features: Lacks deep debugging tools and advanced configurations.

How to Install ZHA

1. Open Home Assistant and navigate to Settings > Devices & Services.
2. Click Add Integration and search for Zigbee Home Automation.
3. Select your Zigbee coordinator and follow the on-screen instructions. I simply use a cheap Zigbee coordinator USB from AliExpress.
4. Once installed, start adding Zigbee devices through the Home Assistant UI. It uses the zigpy library and supports various Zigbee coordinators, including ConBee, Sonoff, and Texas Instruments-based adapters.

What Is Zigbee2MQTT?

Zigbee2MQTT is an alternative Zigbee integration that allows you to connect Zigbee devices to Home Assistant using an MQTT broker.

Pros of Zigbee2MQTT

• Wider Device Compatibility: Supports more Zigbee devices, including lesser-known brands and custom firmware.
• MQTT Flexibility: Can integrate with other smart home platforms beyond Home Assistant.
• Advanced Features: Offers OTA updates, detailed logging, and better debugging tools.
• More Customization: Allows fine-tuned control of device behavior and settings.

Cons of Zigbee2MQTT

• More Complex Setup: Requires an MQTT broker, additional configuration, and possible troubleshooting.
• Higher Maintenance: Needs manual updates and deeper technical knowledge for advanced features.

How to Install Zigbee2MQTT

1. Install an MQTT broker such as Mosquitto via Home Assistant Add-ons.
2. Install Zigbee2MQTT by adding its repository to Home Assistant Add-ons and following the installation instructions.
3. Configure Zigbee2MQTT by editing its settings to match your Zigbee coordinator.
4. Start the Zigbee2MQTT add-on and pair your Zigbee devices through its web interface. It offers more extensive device support and advanced configuration options.

ZHA vs Zigbee2MQTT: Feature Comparison

ZHA vs Zigbee2MQTT: Which One Should You Choose in 2025?

As of 2025, ZHA has become quite mature and is the recommended option for most users due to its simplicity and stability. It is ideal for beginners or those who want an easy-to-use, built-in solution.

• Choose ZHA if you want a simple, plug-and-play solution with minimal configuration. It works best for users who prefer a native Home Assistant experience and don’t need extensive customization.
• Choose Zigbee2MQTT if you need maximum device compatibility and advanced features like detailed logs, OTA updates, and fine-tuned control. It is the best choice for power users or those experiencing issues with device compatibility in ZHA. However, be prepared for a more complex setup process.

The post ZHA vs Zigbee2MQTT: Best Zigbee Add-On for Home Assistant appeared first on TechOpt.

Thanks to sbyx for creating the original blueprint we’ll be using in this guide.

Steps to Creating a Low Battery Notification in Home Assistant for your Smart Home Devices

1. Importing the Blueprint

Open your Home Assistant dashboard and navigate to Settings > Automations & Scenes > Blueprints.

Then, click on the Import Blueprint button in the top-right corner.

Copy and paste the URL to the blueprint, which you can find here.

Click Preview Blueprint, and then Import Blueprint.

At the end you should have a new blueprint named Low battery level detection & notification for all battery sensors.

2. Create an Automation & Configure the Blueprint Values

Go to Settings > Automations & Scenes.

Click the + Create Automation button and select Use Blueprint.

Choose the Low battery level detection & notification for all battery sensors blueprint.

Configure the required values:

• Device List: Select the devices you want to exclude. All devices are included by default.
• Threshold: Set the battery percentage threshold that will trigger the notification (e.g., 20%).
• Notification Method: Specify how you want to be notified (e.g., mobile app notification or email). You can use {{sensors}} in your notification string to list the sensors that are below the threshold.

I set mine to send a notification at 10:00 AM every day of the week, with a threshold of 20%. I send three types of notifications: a regular one through the Home Assistant mobile app, a persistent notification that remains on the Home Assistant dashboard, and another to a shared family email address.

Finally, save your configuration.

3. Test the Low Battery Notification Using Home Assistant

This will work if one or more devices added above actually have a low battery below the threshold, but if not, you can simulate one in Home Assistant.

Simulate a low battery scenario by temporarily adjusting the threshold in the configuration to a value higher than any device’s current battery percentage.

Trigger the automation manually via Settings > Automations & Scenes. Find the automation, click the 3 dots to open a menu and click Run Actions.

Then, confirm that you receive the low battery notification through your configured method.

Once you’re satisfied with the test results, restore the threshold to your preferred level.

Remarks

• This is just one of several blueprint scripts available for setting up a low battery notification in Home Assistant. I like this one because it’s simple and lightweight.

Special thanks again to sbyx for sharing such a useful blueprint with the community!

The post Creating a Low Battery Notification in Home Assistant appeared first on TechOpt.

The projects in this article are ones that the original Model B actually has adequate power to run without sacrificing usability or performance, not just “will run, but not well” projects.

Similarly, a lot of these should work with the Model A. However, keep in mind that the Model A only has 256 MB of RAM, which limits it further.

1. Raspberry Pi Print Server

Make an old USB printer WiFi and AirPrint compatible using an old Raspberry Pi with Raspbian. By connecting the printer to a USB port on the Pi and installing CUPS, you can share your USB printer with your network to make it wireless.

Additionally, CUPS also now supports broadcasting as AirPrint devices. Once the printer is setup in CUPS, you should be able to print to it from your Apple devices as well.

2. Pi-Based Digital Picture Frame

A digital picture frame is probably one of the lowest resource projects you can do. Therefore, this makes it perfect for the original Raspberry Pi. You’ll simply need an old screen with an HDMI input. You can even use a screen with a composite input, since the original Pi has a composite output!

Choose an OS, put your photos on your SD card or a USB key and install some image slideshow software. Some people even get creative with decorative framing around the screen.

3. Raspberry Pi Web Server

You can run a lightweight web server such as nginx or lighttpd on your older Raspberry Pi to serve static web pages and basic websites. You can also try Apache, but keep in mind that Apache is not as lightweight as nginx or lighttpd, so your performance probably won’t be as good.

The original Pi Model B definitely isn’t powerful enough to serve a website to hundreds of users, however, for a few users it should be more than adequate.

4. Self-Host Bitwarden

This is one of my personal favourites. Bitwarden is an opensource password manager that you can self-host. It has accompanying desktop apps, mobile apps, and browser extensions.

The original Pi may not be powerful enough to host full Bitwarden, but it will easily run Vaultwarden. Vaultwarden is an alternative implementation of the Bitwarden API written in Rust, which makes it super fast and less resource-intensive than full Bitwarden. You can still use it with the official Bitwarden apps and extensions.

Simply install docker and spin up the Vaultwarden container. Again, it might not work great for hundreds of users, but our Pi 1 Vaultwarden instance is working great for our family of 6!

5. Internet Radio, Bluetooth or AirPlay Receiver

This one is also a personal favourite to modernize an old stereo system. All you need is a stereo system or set of speakers with an AUX port. This way you can connect the headphone jack of the Raspberry Pi right into the stereo system. Alternatively, if the stereo is older and has an RCA input, you can use a 3.5 mm to RCA adapter.

Install an OS and run your favourite music apps to play directly to your speakers. Additionally, you can setup Bluetooth pairing to use it as a Bluetooth speaker. You can also install shairport-sync to support AirPlay from Apple devices.

Conclusion

The Pi has come a long way since it was first introduced. Even though at first glance the original Raspberry Pi 1 Model B looks severely under-powered by today’s standards, it still has some great uses for applications where a lot of processing power isn’t needed.

The post Raspberry Pi Model B Original (2012) Uses in 2025 appeared first on TechOpt.