Author: Jonathan Oxer

Customise your Sonoff home automation controllers with a memory upgrade, weatherproof housing, control switches, sensors, and custom firmware.

ITEAD keep releasing new Sonoff models so this isn’t a complete list, but some of the models mentioned in the video include:

• Sonoff Basic
• Sonoff Dual
• Sonoff TH10A / TH16A
• Sonoff Touch
• Sonoff POW
• Slampher

Storage

The flash memory chip in Sonoffs is 8Mbit, which is only 1MByte. Then if you want to do OTA (Over The Air) updates you need to limit your program size to less than half the available memory so that a new program can be uploaded alongside the old one. And if you use a SPIFFS (SPI Flash File System) to store non-volatile data outside your program, you lose even more memory.

You can replace the flash memory chip with a Winbond 25Q32FV in SOP-8 package, which is a 32Mbit (4MByte) chip. You can buy them on eBay for about US$3 for a pack of 10.

The original flash memory on the Sonoff is a Winbond 25Q08FV, which is the 8MBit (1MByte) version of the same chip.

Thanks to Pete Scargill for this idea! You can see more on his original blog post: “32Mb ESP01 and Sonoff”

Safety

Sure, you can just cut a power lead and screw it into a Sonoff, but it’s probably a bad idea. You need to consider how your Sonoff will be used, including physical protection (stop little fingers reaching the terminals!) and liquid protection from spills. You also need to make sure there is strain relief on the cables to prevent them being pulled out, and possibly exposing live mains connections. You can do it cheaply using a plastic project box, and with some cable ties around the cables just inside the box so they can’t be pulled out. The result can be a very neat setup that won’t look like a dodgy DIY cable, and should be safe for general use.

You can go even further and use an IP-rated (Ingress Protection) case and cable glands, to make your Sonoff waterproof and physically very strong.

In this video I gave a very simple explanation of the two-digit IP codes. There are also extensions to the code for other attributes. You can find more information and tables showing the specific meaning of the numbers at en.wikipedia.org/wiki/IP_Code.

Switches

Internet control is fun, but usually you also want some way to manually turn the output on or off without using your phone. You can modify a Sonoff to connect an external button across the pins of the built-in button, allowing you to toggle the output by pressing the button manually. The built-in button is connected to GPIO0, so when the button is pressed it pulls GPIO0 to GND. This is used during power-up to put the Sonoff into bootloader mode, and can also be used to toggle the output or do other actions.

Alternatively, you can connect an external button between GND and GPIO14 so that your software running on the Sonoff can detect when it has been pressed. Some firmware, including Theo Arends’s TASMOTA, supports this out of the box.

GPIO14 is exposed on the internal header used to upgrade the software on a standard Sonoff. There is already a pull-up resistor on GPIO14, so you don’t need any other parts. Just connect a button across the GPIO14 and GND pins, and you’re done!

Even better, TASMOTA has an option to support an external switch instead of an external button. The difference is that with a button, you want the output to change state each time you press and release the button. This means the firmware needs to treat both the button press and release (cycling from HIGH to LOW to HIGH) as a single event. But a switch just changes state (goes from HIGH to LOW, or goes from LOW to HIGH) and stays there because it latches in place. So your software needs to treat each level change as a separate event, and toggle the output. Once again, TASMOTA supports this out of the box.

Sensors

As explained in the section about switches, the regular Sonoff exposes GPIO14 on the internal header that is used for flashing new firmware. The same header also provides GND and 3.3V connections, and the GPIO14 pin is provided with a pull-up resistor. This makes it super easy to connect anything that needs a single digital pin, such as an external switch / button or a one-wire sensor.

To make it even easier, the Sonoff TH10A and TH16A both feature a 2.5mm 4-way (TRRS) socket that is intended for connecting external sensors. The socket provides 3.3V, GND, and GPIO14: the same I/O pin exposed on the internal header of a normal Sonoff. That means you don’t even need to modify the board, you can simply plug in your sensor or switch externally.

The 2.5mm socket also has a 4th connection, but there are parts missing inside the Sonoff so it’s left unused. You can fix this easily by putting a solder blob across two pads on the Sonoff PCB, and optionally installing a pull-up resistor.

In the video I said that there is a 10k pull-up from GPIO14 to 3.3V. However, I didn’t notice that there are actually 2 pull-ups in parallel, so the effective pull-up on GPIO14 is 5k! You can still use a 10k pull-up on GPIO4 if you like, or you can use a 4.7k resistor if you want them to be about the same. 4.7k is common for I2C, but 10k is generally fine too.

Software

There are many alternative firmware projects for the Sonoff. Personally I love Theo Arends’s firmware, but there are many others that may suit you better.

To learn about how to install new firmware, see SuperHouseTV Episode #17: Home automation control with Sonoff, Arduino, MQTT, and OpenHAB.

• Theo Arends’s Sonoff-MQTT-OTA-Arduino (“TASMOTA”)
• Espruino
• ESPurna
• Pete Scargill’s HC2016 firmware
• NodeMCU

If you have any other suggestions please let me know in the comments below, and I’ll update this list.

Sites

Because the Sonoff uses an ESP8266 microcontroller, there are a huge number of sites with information that’s relevant to the Sonoff. These include:

• ESP8266 Community Forum
• Theo Arends’s Sonoff Firmware Wiki
• Tinkerman Blog
• Pete Scargill’s Tech Blog
• ESP8266 Hints

The “Flic” Bluetooth button inspired me to create something similar for my home automation system. But instead of using BLE, I just connected a $6 remote control and matching receiver module to an Arduino-compatible board, so that whenever I press the button it publishes to MQTT.

That’s incredibly handy, because it means you can just stick a button anywhere you like and have it trigger arbitrary events in your home automation system. Make it turn off every light in the house, or order you a pizza, or whatever you like.

In this project, I combined it with the ambient tile display that I showed back in Episode #14 so that I would never forget to take out the rubbish bins.

Each week, the home automation system turns on one of the LEDs so that it reminds me to take out one of the bins. A red LED says it’s time to take out the bin with the red lid, and a blue LED means the bin with the blue lid.

Then, when I take out the bin, I just push the button attached to the bin and it tells the home automation system that I’ve done my job. The notification is cleared until next week, when it comes on again.

• Example source code that publishes to MQTT when a button is pressed: github.com/SuperHouse/UniversalButtonEM
• The Flic BLE button: www.flic.io
• The EtherMega board used in the example: www.freetronics.com.au/ethermega
• SuperHouseTV #14: Ambient tile using Arduino, ESP8266, and NeoPixel compatible LEDs

Why mow the lawn yourself, when you can have a robot do it for you?

Husqvarna have very kindly supplied me with an Automower 320, which is a mid-range robot lawnmower that’s suitable to mid to large size suburban gardens.

Normally I like to focus on low-cost, DIY home automation projects, but this is just too good to pass up! In this episode I explain how the Automower works, how it’s different to a traditional manual mower, and (most importantly!) how my pets react to it.

In future episodes I’m going to try some creative things with the Automower. I can’t go totally crazy because the mower is supplied by Husqvarna as part of a pilot program and I’m not allowed to open it or modify it (yet!) but there are still some fun things we can do without voiding the warranty or having it repossessed.

The Automower range is listed on the Australian Husqvarna site: www.husqvarna.com/au/products/robotic-lawn-mowers

Disclosure: Husqvarna provided me with this mower as part of the Test Pilot program. www.automowertestpilots.com.au

Over the years I’ve slowly added individual IP cameras, both inside and outside the house. However, I’ve run into limitations such as how to store footage from the cameras for security purposes, and how to display multiple cameras simultaneously. I’ve used workarounds for these problems but it’s time to try out a proper camera system, rather than a collection of separate cameras.

I installed an ANNKE system a DVR and cameras to replace 4 of my existing IP cameras, to test how well it works. I also installed long video cables and a wireless mouse so I could mount the DVR inside my ceiling and display the camera feed on a couple of LCD TVs, and tested BNC-to-UTP adapters to run Cat-5 cable to a distant camera.

Unfortunately I discovered that the DVR requires Windows for network access, because it relies on a plug-in that doesn’t work on Mac or Linux. That means I had to run long video cables to the TVs that I use to display the live feed from the cameras. The end result is great, but it’s not how I intended to set it up.

This is the particular ANNKE 4-camera system that I installed, which is the Australian version: www.annkestore.com/annke-8ch-1080p-hd-cvi-security-camera-system-with-4-x-2mp-bullet-cameras-c51bp.html

This is the US version of the system: www.annkestore.com/annke-4ch-1080p-hd-tvi-security-camera-system-with-4-x-bullet-cameras-1tb-hdd.html

There are a bunch of other packages as well. The AUD price seems to vary: I think it’s generated by converting from USD at whatever the daily exchange rate is, so it’s different now to when I got mine.

The Sonoff from Itead Studio is a fantastic little mains-switching module with a built-in ESP8266 and WiFi. If you want an easy way to control mains devices such as lamps and fans, this could be it!

Sonoff modules are preloaded with firmware that allows them to be controlled by a phone app, so they’re very easy to get started. But that’s just the beginning: using a USB-serial converter and the Arduino IDE, you can load your own software on the Sonoff and make it do your bidding. I used the Arduino IDE to load a sketch with MQTT support and OTA (over the air) updates, allowing it to be controlled by OpenHAB.

Sonoff models mentioned in this video:

• Sonoff Basic (simplest version)
• Sonoff TH (Temperature / Humidity version)
• Slampher (lamp holder version)

Start by adding ESP8266 support to the Arduino IDE by following the instructions at github.com/esp8266/Arduino. I used the simple “Boards Manager” method.

For OTA (over the air) update support you’ll also need to install Python 2.7.

You’ll also need a USB-serial converter with support for 3.3V I/O. I used the Freetronics USB-Serial Converter (of course!), which has a switch that lets you select 3.3V or 5V mode.

The “BasicOTABlink” example shown in the video can be found at github.com/superhouse/BasicOTABlink.

The “BasicOTARelay” example shown in the video can be found at github.com/superhouse/BasicOTARelay.

For more information, a fantastic resource is Pete Scargill’s blog post about Slampher and Sonoff.

If you want to upgrade the FLASH memory on your Sonoff, check out Pete Scargill’s blog post about upgrading ESP8266 memory.

Update 24 Sep 2016: fixed the example links.