Category Archives: Hacking

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Sonoff B1, lights and shades

Six months ago I was reviewing the AiThinker AiLight, a great looking light bulb with an embedded ESP8266EX microcontroller, driven by a MY9291 LED driver. Just before summer IteadStudio released it’s Sonoff B1 [Itead.cc] light bulb, heavily inspired (probably same manufacturer) by the AiLight, at least on the design.

Now that IteadStudio has become popular between the home automation community you can also find the Sonoff B1 on global marketplaces like Ebay or Aliexpress for around 13‚ā¨.

A closer look at the B1 uncovers some important differences. But before going deeper into the details let me first say that this post will probably look more like a review, at least more than I use to write. And second, yes: ESPurna supports the Sonoff B1 ūüôā

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Connected power meter

A few weeks ago a user came with a request to add support in ESPurna to a power meter that had been hacked by Karl Hagström. It is a very cheap chinese power meter with plenty of room on the inside, enough to house an ESP8266 module and a DC/DC power supply and the main IC protocol had been reverse engeneered. There even was a repository by the Harringay Maker Space with sample code for an arduino compatible platform.

I found it really interesting so I jumped in and ordered two of them (for 25,20 euros in total). Unfortunately the seller I bought it from has ran out of them. But you can still find them on the usual market places, like these ones [Ebay] or (also with non-EU variants) these ones [Aliexpress].

When I received them I quicky unscrewed the enclosure of one of them and… wow, it looked slightly different than that on Karl’s post but also different from the one the people at Harringay Maker Space had worked with.

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I went back and forth and I¬†noticed the hack was almost 2 years old¬†and the board was clearly different: different version (unlabelled on Karl’s pictures, version 2014-04-28 on Harringay’s power meter and 2016-12-18 on mine), different board layout with a different connector between the power meter board and the display (7 wires on theirs, 6 on mine). But the most important difference was the main power meter IC. Karl had reverse engineered the ECH1560 on his power meter, a 24pin SOP package (on the back on his device, on the front in Herringay’s power meter). Mine was only¬†16pin…

p1240274sI had to decipher the IC mark¬†using parts from¬†both devices since the manufacturer had crossed out the marks (they don’t want us to hack it or what?). Finally my best guess was V9261F. I quicky googled it and… bingo!

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AiLight – A hackable RGBW light bulb

Some weeks ago a tweet by Manolis Nikiforakis (@niki511) with the¬†#ESP8266 hashtag drew my attention. Manolis had just received a “smart lamp” branded by Ai-Thinker, the AiLight. Yes, the same Ai-Thinker that¬†has sold millions of ESP8266 based modules. Chances were it had an ESP8266 microcontroller inside. Too good not to buy one and take a look at the inside.

Manolis shared the link where he bought his at Ebay for a bit more than USD 10 plus shipping. Unfortunately it’s out of stock there and there are amazingly few other places where you can buy it. I only¬†found the same product with prices around USD 15-18 at Ebay as¬†ESP8266 Smart Home Wifi RGB LED Light¬†[Ebay] or¬†Noduino Open Light LED Smart Bulb¬†[Ebay] also in a cheaper¬†pack of two light bulbs¬†[Ebay]. You can also find it at Aliexpress sold as “DIY Wifi LED Bulb E27 5W AC110-240V lampada LED Dimmable Bulb Lamp Remote Control Led Spot Light for iPhone Android Phones” [Aliexpress]. Don’t you love¬†those seo-ugly names?

I actually bought two because you never know. And they arrived last Thursday. It took me less that 1 minute to open one of the boxes, pop out the cap¬†and take a look at the inside just to see what I already knew. Time to play ūüôā

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Smart wall switches and push buttons

One might think that one of the typical uses¬†for a smart wireless switch (like Sonoff devices) is to be embedded behind a normal wall switch so it becomes a “smart” wall switch. It may seem obvious but it’s not that straight forward. There are several things that get in the middle.

  • Most (all?) the boards have momentary push buttons while wall switches are (normally) toggle switches
  • Most of the available boards in the market are SPST, even those with SPDT relays often only provide terminals for COM and NO, not NC. I only have one one-throw switch at home, all the others are one-way-two-throw and are being used as part of a multi-way switch.

First problem can be easily solved in code. Instead of detecting one edge of the button signal (usually the rising edge since most push buttons are configured with pull-ups) you can detect both edges.

Second problem is harder since it depends on the hard-ware (ehem). But there are a few boards out there with SPDT relays like the Itead 1CH board I recently covered, the e_Goto Wifi Relay Switch Module [Aliexpress] or the Your Cee ESP8266 5V WiFi Relay Module [Aliexpress]. There are also two-relay boards you can use for a multiway switch by syncing the relays in opposition mode using ESPurna firmware for instance (one and only one relay on). The Electrodragon ESP Relay board is one such boards. Another one is the Sonoff Dual.

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The Electrodragon ESP Relay board and Itead’s Sonoff Dual

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Sonoff SC with MQTT and Domoticz support

Last December Itead Studio updated their Home Automation product line with a new and different product. The main difference is that it doesn’t have a relay and it’s mainly sensors and no actuator (if we don’t define a notifying LED as an actuator). The Sonoff SC is a sensor station that packs a DHT11 temperature and humidity sensor, a GM55 LDR, an electret microphone with an amplifier circuit and a Sharp GP2Y1010AU0F¬†[Aliexpress] dust sensor in a fancy case that looks like it was originally meant for a speaker.

The device is packs an ESP8266 as expected and is compatible with the eWeLink app. But, such a collection of sensors, with 3 of them having analog interfaces, cannot be run from the single-ADC ESP8266 so Itead has thrown in a good old ATMega328P to drive the sensors and report the Espressif with the data.

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