It’s not that other Sonoff products are not “serious” business, but there are a number of design changes in the Sonoff S31 that make this new product a world apart. For the functional point of view it looks like a S20 with POW-powers, but they have redesigned the product completely. The result is very very interesting.
Revamped case, more compact and sturdy
Redesigned PCB, actually 2 different PCBs for main and control
Different power monitor chip: the CSE7766 (same as in the new POW R2) replaces the HLW8012
The only drawback: it’s only compatible with plug types A & B, tat is central and north-america and few other countries. I’d love to see a S31-EU schuko version!
You can buy the S31 from Itead (see link above) or via the usual marketplaces. Actually the S31 is slightly cheaper [Ebay] on some of them.
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€.
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 🙂
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.
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…
I 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!
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.