esp8266_inside

Emulate a WeMo device with ESP8266

My daughters love to talk to (or with) my Amazon Dot in their funny English: “Alexa, hello!”, “Alexa,  li-on!” (actually “light on”). It’s so easy to use it to switch on/off things at home using the fauxmo python script by Maker Musings. In his post about Amazon Echo and Home Automation more than a year ago he explains how he reverse-engineered the protocol of the WeMo switches that Alexa (Amazon Echo or Amazon Dot) supports.

I also have a server running the fauxmo script with an MQTT handler to control some of the Sonoffs I have at home, but this morning I woke up thinking: why should I use an external script to control my devices if I can code it in the firmware?

Continue reading

20161105_112709x

The Sonoff POW

Some months ago I wrote about a hack I did to one of my Sonoff devices to be able to use a simple current sensor to monitor my washer machine process and alert me whenever my laundry was done.

A few weeks ago Itead Studio released two new models for their Sonoff line, the POW and the DUAL. And the POW is Itead’s answer to my hack. I’m not saying they copied me, just that the Sonoff POW makes my hack utterly unnecessary. Do you want to remotely monitor your devices energy consumption? Buy a POW.

Continue reading

hlw8012

The HLW8012 IC in the new Sonoff POW

The HLW8012 is single phase energy monitor chip by the chinese manufacturer HLW Technology. It features RMS current, RMS voltage sampling and RMS active power with an internal clock and a PWM interface in a SOP-8 package. You can buy it at Aliexpress for less than a euro a piece and the necessary components are fairly easy to source and quite cheap.

All in all it looks like a great IC to include power monitoring in your projects. I guess that is why Itead Studio chose it for the Sonoff POW, one of their newest home automation products. And of course I have a POW here in my desk and I’ve been playing with it this weekend. The goal is to support it in my Espurna firmware but first I wanted to know more about the HLW8012. I’ll write about the Sonoff POW in a different post later this week.

Continue reading

20161019_095810s

Controlling 4DSystems Diablo16 and Picaso displays from Python

A few week ago I had a really good time testing 4DSystems 4Duino-24 board. One of the things I noticed is that the Serial Command Set interface is really flexible. You can easily drive the display from an 8-bit microcontroller. But you can also use more powerful controllers like an ESP8266 or an ARM machine like a Raspberry Pi or even my laptop.

4DSystems provide libraries for all those platforms and others. Most of those libraries share a common language: C (they have also developed libraries in Basic for PicAxe and Pascal). But even thou I spend a lot of time write C code, when I’m on my laptop a prefer higher level languages like Node.js or Python. So why not using Python to control these displays?

Actually, Python being written in C itself has a great support to wrap C libraries so you can use them from the language. Using Python to develop has several advantages:

  • Powerful language with complex but easy-to-use data structures
  • Rapid development since it’s an interpreted language
  • Mostly platform independent (you still need to compile the C libraries for your platform, but the wrapper and example should work without modifications)
  • It’s cool

Continue reading

20161009_021036s

Low power weather station with BME280 and Moteino

A few weeks ago I wrote about my new door monitor. It was the first step towards migrating my XBee based wireless sensors network to RFM69 radios using Moteino platform by LowPowerLab. I was truly impressed by the low power consumption so I committed myself to keep on working with them.

Coincidentally Felix Russo, the guy behind LowPowerLab, released the new version of it’s Weather Shield for Moteino. So it was time to update (or completely revamp) my trusty Arduino FIO based weather station… and last week I received a parcel from LowPowerLab with a pair of shields to play with: the new WeatherShield R2 and the PowerShield R3. They are both compatible with the Moteino (off course).

Moteino PowerShield and WeatherShield

From left to right: PowerShield R3, Moteino and the new WeatherShield R2

Continue reading