Category Archives: Projects

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Useful notifications from your home appliances using Node-RED

Some time ago I worked on a home project to get a notification when my washing machine had done its job based on monitoring its power consumption. There was a good reason for that, the machine was outside the house and I had already forgotten about the laundry several times. And when that happens your only option is to wash it again, because it really smells musty…

Monitoring your appliances

Use ESPurna 🙂

OK, there are different ways to get the info about power consumption. But since we want to be able to process the data ourselves most commercial products won’t be suitable unless we modify it.

Alternatively, those that use radio communication to send data from the meter to the base station might be suitable for a man-in-the-middle hack. For instance, if you own an Efergy power meter you must know you can sniff the data it sends using a simple RTL-SDR dongle.

But for most cases, your best chance is to get your hands on a commercial product with an ESP8266 chip in it and change the firmware to suit your needs. You can write your own or use an existing firmware like ESPurna, that already supports a bunch of power metering smart switches.

What info do you need?

The idea is to report (via MQTT) power data from each individual appliance very minute. You can then use Node-RED along with InfluxDB and Grafana (or Graphite) to receive, persist and graph your data like in the image below.

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RAK833 meets Raspberry Pi

You might have heard about The Things Network (TTN from now on) here or somewhere else. If you have not, then it’s a good opportunity to visit the project and check if there is a community of users around you. I have been a core member of the TTN Catalunya community for over 2 years now. This year we are working hard deploying several new gateways in Barcelona and doing workshops and hackathons with the main goal of helping individuals and social entities to carry out projects around a LoRaWan open, libre (free as in freedom) and neutral telemetry network.

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M5Stack node for The Things Network

I have a couple of IKEA-like boxes in my home office labeled “Inbox”. They are full of stuff I buy and store waiting for some free time to spend on them. From time to time I pick one of the boxes and take a look at its contents. They are actually full of “wow” stuff. I would buy again most of the things there but at the same time I fear I’m just collecting stuff that will become junk.

I couple of week ago I rescued from one of those boxes an M5Stack Core Development Kit and some other stuff that was there for maybe 6 months.

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GeekWorm Power Pack Hat Hack

Sorry for the tongue twister 😉

I’ve been somewhat busy lately and it’s been a long time since my last post. I have a few projects on the go but not much time to sit down and write about them… Let’s see if this one goes through…

I’ve been lately looking for a reliable UPS system for Raspberry Pi 3. I moved my home server to a RPi a few months ago and even thou its behind an ACS UPS a couple of other projects involving RPis required mobility (one of them) and unassisted power backup (the other). So I started browsing several marketplaces looking for a solution.

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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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