This article is greatly delayed, as I accidentally killed my Sonoff DualR3 during my review. If you want to know what happened and laugh at my mistakes, feel free to check the article out. ITEAD was kind enough to send me another one, knowing that I will disregard their eWeLink app and jump straight into flashing. Unfortunately, the method isn’t as simple as with other ESP8266 based devices as Sonoff DualR3 is ESP32 based and all-new ITEAD devices will be ESP32 based as well.
Tasmota on Sonoff DualR3
I’m sad to report that Sonoff DualR3 doesn’t even come with Sonoff DIY mode, which would make thigs easier. The DIY mode is good enough for most of my uses, but if you want to take Sonoff DualR3 a step further, you have to flash the device in a more traditional way. I will have to reach out for my good old soldering iron (I recently upgraded from TS80 (review) to TS80P (review pending) and FTD1232.
As brilliant Tasmotizer for ESP8622 devices is out of the picture, I had to look elsewhere to get the tools for the job. Thankfully, some work already been completed in this GitHub discussion, so I will base my tutorial on their findings.
List of downloads:
- ESP Flasher (exe)
- FTD1232 driver (exe – in case the flasher can’t detect the COM ports)
- Tasmota.bin (ESP32 Sonoff DualR3 edition – this is a custom build)
To flash Tasmota on Sonoff DualR3, you will need to connect the usual pins to the device. Thankfully, dev pads are properly exposed, and the button is linked to GPIO00. Follow the table below to connect your FTD1232 (or similar) to Sonoff DualR3:
| Sonoff DualR3 | FTD programmer |
| 3V3 | Vcc/3.3v |
| GND | GND |
| RX | TX |
| TX | RX |
Do not flash the ESP32 with Sonoff DualR3 connected to mains. FTD1232 is enough to power the pins and flash Tasmota on Sonoff DualR3. To enter flash mode, hold down the button on Sonoff DualR3 while power cycling the device.
ESP flasher & custom Tasmota firmware
Software is self-explanatory, open the software, select the tasmota32.bin from your drive, select the port to which the device is connected and hit flash. You should be done in a couple of minutes. If all went well, you should see “tasmota-XXXXX” SSID after reboot. Connect to that SSID and navigate to 192.168.4.1
Enter credentials (and hostname) and reboot your device. You can use the Fing app to find the device on the networks again or use the hostname. Navigate to Configure->Configure Other and use this template to configure Tasmota on Sonoff DualR3. After reboot, you should see a familiar menu with 2 channels to toggle and energy use information.
{"NAME":"Sonoff Dual R3","GPIO":[32,0,0,0,0,0,0,0,0,576,225,0,0,0,0,0,0,0,0,0,0,7296,7328,224,0,0,0,0,160,161,0,0,0,0,0,0],"FLAG":0,"BASE":1}Bear in mind, that this firmware is a custom build. I have compiled this from source, and until properly integrated with the tasmota32 dev branch. Upgrading the firmware with binaries from the official channel may break the functionality of Tasmota on Sonoff DualR3.
Going further
Despite being in beta, Tasmota for ESP32 works pretty well, the interface is responsive and updates switch state changes reasonably quickly (about 1 sec). Power metering accuracy is on par with what I got with the eWeLink edition, the only thing that is not present is the data logging. This is something you will have to do yourself. My recommendation would be to use Grafana and InfluxDB – and as it happen, I have a handy tutorial for you to get you started.
Now, you will be able to take advantage of the REST API and MQTT. If you want to learn how to integrate these with NodeRED – I have tutorials available already. If you need Alexa integration – here is an article for you, and for Google Assistant – take advantage of NORA. Should you wish to recreate fancy features like inching or interlocking – I also covered this for you.
Final Thoughts
Although Sonoff DualR3 comes without DIY support, flashing Tasmota on Sonoff DualR3 isn’t a total pain in the neck, and has to be done just once. I hope that ITEAD will rethink the approach to new devices and add Sonoff DIY by default. My source tells me that all future Sonoff devices will be ESP32 based, so it would be nice to see Tasmota and Tasmotizer evolving more in that direction. If you have any comments, feel free to let me know in this Reddit thread.
