Posts Tagged ‘sonoff-tasmota’
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Review of Sonoff B1 Smart RGB Light Bulb – Part 2: Sonoff-Tasmota Firmware

October 5th, 2017 1 comment

I’ve already reviewed Sonoff B1 light bulb using the stock firmware combined eWelink app for Android, and as promised in the first part of the review, I’ve also tested the ESP8285 based WiFi light bulb with Sonoff-Tasmota open source firmware, and report my findings in this new post.

Before we can play with the new firmware, we need to install it, and I’ve just explained how to upgrade Sonoff devices to Sonoff-Tasmota firmware either using some soldering skills and a USB to serial board, or some network configuration skills and perform an OTA update using ITEAD Studio/eWelink original firmware update mechanism.

So for this part of the review, I’ll assume we have just freshly update the light bulb with Sonoff-Tasmota using the binary images released by the developer. First, you’ll need to find the IP address of the light bulb with your router or tools like nmap or arp, and access the web interface in your web browser with for example You’ll probably want to setup a fixed IP address for easier access later on. By default the firmware is set to use Sonoff Basic, but we can go to Configuration->Configure Module, to change that to Sonoff B1, and click Save.

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This will reboot the light bulb with Sonoff B1 configuration, and you should be able to turn on the light bulb by adjusting the Color or Brightness sliders, or pressing the Toggle button.

It works with some lag, one or two seconds, just like on the eWelink app. What you don’t get in the current web interface is the ability to adjust RGB values, so only the white lights can be controlled easily. More on RGB control later. You’ll also lose timer and schedule ability from the web interface, because that’s more of a task for your home automation server using either MQTT or Domoticz whose options are available in the Configuration menu as shown below.

Configuration, MQTT, and Domoticz – Click to Enlarge

I won’t explain how to use those in details, as Karl’s has already written a tutorial using MQTT it with his home automation project with Sonoff-Tasmota (aka arendst’s firmware), and one my side, I have published instructions to setup MQTT and Domoticz with ESPurna open source firmware for a Sonoff POW switch.

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Other menus in the configuration include reset/backup/restore configuration, logging parameters, and other parameters such as Belkin Wemo or Hue Bridge emulation. If we go back the back to the main menu, we have some more buttons beside Toggle and Configuration such as access to the console, which you can use to monitor the output log, and send various commands, including ones to control the RGB lights. For example, I could set to the light to green with the command “Color 00FF000000”, since for Sonoff B1 they use hexadecimal values for Red, Green, Blue, Warm White, and Cold White. You can also use those commands over serial, MQTT, and a web API. For the latter the command

will set the color to red, and return:

Other options include Information with a complete overview of most parameters…

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Firmware Upgrade to do so either from an update server, or a local file, and Restart to reboot the device.

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Sonoff B1 with ITEAD Studio’s stock firmware and eWelink app is pretty much plug and play, and you can control multiple lights from one app, configuring the white and RGB lights, and setting timers and schedules, all right from your smartphone. The downsides are that it requires the Internet to communicate with the cloud service, the firmware and app are both fully closed source so you can’t add features or easily integrate it with your home automation system using standard protocols such as MQTT or a REST API. It does integrate with Amazon Alexa or Google Home however.

Going the open source firmware route is more a hack-flash-configure-get confused-setup-learn-and-play solution. Once you have overcome the steps to upgrade firmware to Sonoff-Tasmota, it’s not at all convenient to control your devices from the built-in web interface, especially if you have many. The firmware has really been designed to use with an home automation gateway like Domoticz, where you can manage with your lights or switches from a single web interface. So you’d have to setup your gateway, and you’ll likely get an Android app with it to do something like eWelink app, except you’ll have much more flexibility. You can get a bunch of lights to change colors in sync with your music (likely with a short delay), turn them on when motion and low light conditions are detected, or when specific persons are detected using face detection, etc.. The limit is only your imagination, and willingness to learn new skills.

I’d like to thank ITEAD Studio for sending a review sample. If you are interested, you can purchase the light bulb directly from them for $18 plus shipping. It can also be found on sites like Amazon US or Banggood.

Upgrading Sonoff Stock Firmware to Sonoff-Tasmota – USB to Serial, and OTA Update Methods

October 4th, 2017 7 comments

This post was initially supposed to be part 2 of Sonoff B1 light bulb review, where I would have explained how easy it was to use OTA mechanism to update to Sonoff-Tasmota open source firmware, and shortly show about its features and capabilities. However, it took me over 10 hours to make that work, mostly due to misunderstand in the documentation, and time spent to configure routers. I also failed the first time with Sonoff B1, so I used the serial console method, and instead managed to use SonOTA method with Sonoff POW switching from stock firmware to Sonoff-Tasmota without having to solder or tear down anything.

Updating software with a USB to Serial Board

Using a USB to serial board is the most common method to switch from stock firmware to open source firmware such as ESPurna or Sonoff-Tasmota in Sonoff devices or other ESP8266 based devices. It’s quite straightforward with Sonoff switches like Sonoff TH16.

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You just need to solder a 4-pin 2.54mm pitch header, connect the board, and use esptool to flash the image. One it’s done you can simply remove the wire, leave the header in place, and put the case back in place. But with Sonoff B1 light bulb, it’s quite as easy. First there are no through holes in the board, and you need to solder up to 6 wires on small solder pads.

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The GND, Tx, Rx, and 3.3V must be soldered and connected to the USB to serial board, while GPIO0 must be shorted to enter programming mode, so I also added two more wires for GPIO0, and an extra GND pin.

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Important warning: Never connect the serial board and AC/mains at the same time. Your equipment and life may be at risk.

Now we can download the latest version of the firmware, install esptool, connect the USB to serial board to your computer – which will also provide powered to the board -, and run esptool to flash the firmware:

That’s pretty straightforward, and the output should look as below if everything runs normally:

Most products on the market defaults to access point mode when they are first booted, but Sonoff-Tasmota’s developer have instead decided to provide pre-built image in client mode connecting to a default access point with SSID: indebuurt1 ; password: VnsqrtnrsddbrN. That’s a bit of a pain, as you need to configure another router with those credentials, before changing it to your home router. An alternative way is to build some source, and change the default AP settings, so the device can connect right away after flashing. Still, I’d wish an image that default to AP mode would be nice. It’s actually not a problem for most Sonoff devices, as you can switch to AP mode with the button (4 short presses), but Sonoff B1 does not have one.

Now imagine you have a dozen or more of Sonoff B1 light bulbs that need to be update to Sonoff-Tasmota. That would be a real pain to solder and unsolder the required wires for each bulbs. One solution is to create a jig with pogo pins for firmware update, as the one shown below specifically designed for AI Light. You just need to pop out the bulb, click the jig, flash over serial, remove the jib, refit the bulb, and you’re done.

I don’t know if one exists for Sonoff B1, but the jig above could certainly be customized to work with it.

SonOTA – Sonoff OTA Firmware Update Method

However, in an ideal world you’d prefer not to mess with the hardware at all. If only ITEAD Studio provided a way to upload custom firmware with their stock firmware that’d be ideal, but it’s not the case right now. Luckily, the OTA mechanism was reverse-engineered, and SonOTA is an (experimental) implementation that allow to flash alternative firmware to Sonoff devices without altering the hardware or needing special jigs.

The method on Sonoff-Tasmota wiki does not work on Sonoff B1 because there SSID is not advertised in pairing mode, but somebody in github had managed to update one light bulb using DNS spoofing. Since I used the first method with Sonoff B1, but only partially managed to make it work, I switched to Sonoff POW, and succesfully tested the DNS spoofing method.  Several items are required, so I’ve drawn a diagram showing how those interact.

  1. The Home Router is just the WiFi router you’d normally use to access the Internet
  2. The smartphone with eWelink is requirement to configure WiFI on the Sonoff device, and update it to the latest stock firmware version. It can also be used to easily check access points.
  3. The WiFi laptop runs SonOTA, and will act as ITEAD Studio firmware update server located at (for example,, etc…)
  4. “Temporary” Router with DNS spoofing will make sure redirect to your laptop/computer running SonOTA, so it takes over when Sonoff device tries to update the firmware. It still needs to be connected to the Internet.
  5. Sonoff device – The device we want to update

Potentially, you could combine the router, router with DNS spoofing, and WiFi laptop into one device, if you have a Debian based router, but I still separate all three in my case, since home router does not support DNS spoofing, and I failed to install SonOTA on the temporary router.

The very first step is to pair the Sonoff device with eWelink app, connect it to your home router, and update the firmware to the latest version, in my case 2.0.4.

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Now you can configure your temporary router to use DNS spoofing. I did not have any spare router with such feature, so I instead used VS-RK3399 board with Debian, and configured it as a router with hostapd, and isc-dhcp-server using those instructions. This part will heavily depend on your router, and whether you use Debian, or other Linux distributions. For reference, here are some of the main configuration files I used:

  • /etc/hostapd/hostapd.conf

  • /etc/network/interfaces

  • /etc/dhcp/dhcpd.conf

The next step was to configure DNS spoofing. I first went with dnsmasq, and I could successfully confirm it worked with dig, but for whatever reason Sonoff B1/POW would still connect the ITEAD server. Finally I tried with dnsspoof, and it worked OK.  Installation in Debian:

/etc/dnsspoof.conf configuration file to redirect traffic to ITEAD / eWelink update servers to my WiFi laptop:

You can run it as follows:

DNS spoofing took me the most time, as beside restarting service in the router itself, you have to restart the devices connected to it to reflects the changes. I also messed with /etc/hosts file in the router and laptop, but it should not be necessary, as the important is to fool the Sonoff device.

Let’s switch the WiFi laptop configuration. It should work with both Linux and Windows, but mine is running Ubuntu 16.04, so that’s what I used. Let’s create a working directory, get SonOTA code, and install all required libraries and tools.

Now we’re ready for the update. Launch SonOTA script in legacy and no provision modes:

This will first ask you to select the WiFi interface, and enter your SSID and password, and start probing for the Sonoff device:

Delete your Sonoff device in eWelink app, and restart pairing, this time connecting it to your temporary router with DNS spoofing enabled, and shortly after the SonOTA script should start to transfer the image to the device:

Now you should be able to use your smartphone or the laptop to connect to FinalStage access point, start a browser to access You should see the interface below, click on scan for Wifi network, and select the one you want to replace indebuurt1 SSID, in order to connect to your “home router”.

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Click on the button Save on the bottom of that page, and after a while you should be able to access Sonoff web interface into your home network

Output log of script for that last step:

Success! Finally… Now you can configure Sonoff-Tasmota to use your actual device – in my case Sonoff POW – instead of Sonoff Basic. I’ll show a bit more about that while testing Sonoff B1 with Sonoff-Tasmota in an upcoming post. Whether you choose between the serial or OTA method will depend on the number of devices you have to update, and/or whether you prefer soldering or messing around with network settings. If you are after maximum efficiency for a large number of Sonoff B1 light bulbs, then a jig with pogo pins should be by far the fastest way to reflash them all.

Review of Sonoff RF Bridge, Sonoff 4ch Pro, and Sonoff POW with Sonoff-Tasmota Firmware

September 12th, 2017 No comments

Karl here. Today we are going to look at 2 new and one older Sonoff devices.

I spent very little time with the stock firmware on the device. I don’t like the fact that an Internet connection is needed, and I am not in control. As of the time of this writing I found the Ewelink was not configurable enough to meet my needs. There is one feature that is really nice that I could easily see keeping stock firmware. It is the Alexa Skill. It worked. I am also currently reviewing Vobot Smart Alarm Clock with Alexa integration and had no trouble controlling the Sonoff devices with Alexa. But unfortunately I am lazy and want everything automatic so I can’t keep it. With the RF bridge I was unable to trigger a light from a motion sensor. In comes Arendst ‘s Sonoff-Tasmota firmware  to the rescue. It gets better all the time. It is dead simple, and so configurable now. He continues to add features and devices.

RF Bridge

You may have seen my previous article building a 433toMQTTto433 bridge to use cheap 433mhz devices. I never did build a case for it, and it’s a little bit of an eyesore. When I found out about a nicely packaged one, I was excited to check it out. Like I stated previously, it didn’t work as I anticipated and was glad when I found out Arendst got one as well. He has a good wiki with on the github page and all the needed information to flash and configure so I won’t go into it. It flashed uneventfully. I was a little scared by the design that it was only going to be able to receive 16 individual codes and pass onto MQTT but that is not the case. It passes everything it receives. You can only send 16 different codes right now which need to be saved ahead of time. So after monitoring the MQTT server I ran into first hurdle. I was getting this example json value.

And actually I found after much frustration that “Data” is a nested json value. This took a while for me to figure out. After that it was relatively easy to parse in Home Assistant and move my automations over from the previous bridge.


From the previous article payload off is a made up value and is only used internally to turn the sensor off after a minute.

Just a couple gripes about the rf bridge which are superficial. There is a noticeable increased delay over the homemade bridge from the time it senses a trigger until the light comes on. It is only about half a second but a noticeable difference. And my wife pointed quickly that the led indicating it is on is very bright. I might remove it or install a varistor to tone it down. The receiver does not appear to be as good or might just be that it is in a case or my positioning. I am still able to cover my house but the trigger on my mailbox across the street doesn’t trigger. It was hit or miss on the old one but never triggers now.

FYI I am still running off the same batteries I initially installed in the 433mhz motion sensors over 6 months ago.

Sonoff 4ch Pro

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I also received the Sonoff 4ch Pro with 433mhz transmitter remote.

I tested it with stock Ewelink software and all tests done before worked. I quickly installed the alternative firmware from above, and again no loss in functionality. I was still able to pair and clear the 433 MHz remotes. It is weird that it does not indicate with a light that it is in pairing mode as of right now but when you press the button the light blinks when it is learned. The inching, self locking and interlock continued to work as well via switches. I can definitely see this being used for lighting, or if you needed to control multiple items in close proximity. Maybe simple access control. Possibilities are endless. On the product page, it shows wiring with motors as well which looks cool. If I find a unique or interesting project I will share.

The 4 button transmitter is very powerful. It transmits further than any of my other 433mhz devices.

Sonoff POW

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A buddy of mine gave me a Sonoff POW to play with. The Sonoff POW is very similar to the Sonoff Basic, but has the ability to measure power usage. I didn’t bother testing the stock software. I went straight to Arendst software. I didn’t have anything to measure power before and this is a welcome addition to my tools arsenal. I don’t need super accurate readings just a good idea what the draw is. I installed a light rated at 75w to test and got the results below. If a more accurate load is available you can calibrate the POW and instructions are in the Wiki.

OTA Firmware

Who wants to drag all their devices back to the PC and flash new firmware? I finally checked it out. It is really simple to do.

First uncomment BE_MINIMAL then export compiled Binary. After a while you will have a bin file in your sketch folder.

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After uploading comment BE_MINIMAL, upload again. The 2 steps procedure is because he is running out of space with all the features. He is trying to reduce the code down, and hopefully make this a single step in the future. If you have a web server there are instructions to automate this.


I would like to thank Itead Studio for sending the Sonoff RF Bridge, 4ch Pro and 4 button 433 MHz transmitter. They keep expanding their Sonoff line and make them hacker friendly. I would also like to thank Arendst for his tireless work on Sonoff-Tasmota firmware. If you are just looking to control your lights via Alexa, and don’t mind requiring the Internet to be available the stock firmware might work for you.