Category Archives: Learning

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Using Google Assistant to control your ESP8266 devices

In my last post I tried to explain how to access your IoT devices at home from the Internet in a secure way using a reverse proxy. Truth is that I had it running since maybe 6 months ago without giving it too much use until recently. Reason? My Nexus 5 had been having serious problems (battery not charging, screen broken, earpiece not working,…) and I decided to replace it with a new mobile phone and the new one has Google Assistant built in.

So one of the first things I have tried is to make Google Assistant toggle my smart switches flashed with ESPurna. Nad as it turns out it’s not hard to do but -at the moment- you have to relay on a cloud service like IFTTT (IF This Then That). This is a key difference with Amazon Alexa services you have to be aware. It has some benefits but also some drawbacks.

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Secure remote access to your IoT devices

When you are hacking with IoT devices at home you get to face the challenge of accessing remotely to them, that is from outside your home network. I’m not saying your home network is a safe place, beware. But that thing outside, you know, “the Internet”, it’s so scary… Unfortunately, most IoT devices are just not ready for the jungle. Neither the commercial ones, nor the hacked ones you might have. I wouldn’t dare to open a port in my router to anything inside unless it’s encrypted. So what should we do?

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Embed your website in your ESP8266 firmware image

A few months ago I wrote about the process I was using to optimize my website files for SPIFFS prior to upload them to the ESP8266. The goal was to reduce the number and size of the files to help the microcontroller to cope with them in an easier way. Smaller size mean faster downloads and less files mean less concurrency.
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The mysterious IC

Sometimes Chinese manufacturers throw a mysterious, unlabelled, IC into their designs so we can spend a few hours trying to figure out what they are and what they do. It’s such fun! I’ve been playing with one of those this afternoon, trying to answer those questions but also trying to understand why! Why is that chip there? Why did someone decided she needed that chip there?

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Some weeks ago a user of ESPurna asked me if the firmware supported Itead’s 1CH self-lock/inching board. My answer was “why not” since all Itead’s products are very much alike. Wrong. This one is different. Let me summarise why:

  • There is no entry in the Itead’s wiki for the device
  • There are no schematics, drawings, in the store
  • It uses (and brings out) a Songle SRD-05VDC-SL-C SPDT relay (there is only one other product using this relay in Itead Studio store)
  • It uses Itead Studio PSA-B module
  • It does not have an AC/DC transformer
  • My module supports 12VDC connection
  • It features a second button exclusively for the pulsing feature
  • There is no header to program the PSA-B module

All these things together kept me wondering… is this an Itead’s product?

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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.

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