Internet connected power usage monitor

Our homes are filling with energy hungry devices. Some of them are constantly active like fridge, routers, lighting, some switched off or on stand-by. Each of them takes some portion of energy that reflects on the end month bill. Some things you can control, but some not. So in order to hunt inefficient nodes you need some sort of energy usage monitoring.

You can find lots of implementations where some are simple indicators, other are advanced and web enabled.


TSalwach @ have built his own version of energy monitoring system which looks really promising. His implementation monitors all three phases where he extracts several parameters:

RMS Voltages and currents on each phase

Apparent power (product of RMS voltage and RMS current)

Real (active) power

Reactive power with inductance/capacitance indication (time delay method *)

Power factor

Frequency (zero crossing detection with linear interpolation)


Tariff indication

Costs of energy and alternative cost (on single tariff)

He used two microcontroller boards to for this task. First one is Raspberry Pi which takes care of web accessibility, data storage and interpretation. The other is Nucleo board with STM32F072RB ARM microcontroller. This is a front end which collects data from AC sensing transformers.

Tearing Raspberry Pi Zero apart

Raspberry Pi Zero is really minimalist but yet powerful minicomputer featuring all necessary parts required to run Linux or other operating system. It features Broadcom BCM2835 processor at 1GHz, 512MB of DDR2 RAM, micro-SD slot, mini-HDMI capable to output 1080p60 video, micro USB for data and power, 40-pin GPIO, unpopulated composite video. All this fits in to 65mm x 30mm x 5mm form factor. Price for it is ridiculously low – $5. you may need micro-USB to USB adapter and HUB if you would like to have WiFi functionality, or connect keyboard. It is ideal small embedded Linux based board that is more power efficient than standard Raspberry Pi boards and still can run powerful control applications. Lets leave this topic to other debates.

electroupdate shared his video where he tears one Raspberry Pi Zero apart. Simply speaking there is nothing much to tear. But probably most interesting part is processor and memory sandwiching called package on package (POP). This great solution to squeeze several chips in to small space. In other hand this practically takes out any chances to upgrade system.

He peels of memory chip and in the bottom there is a processor – he even puts die under microscope where part number and whole processor circuitry is visible. Then he moves to other parts of PCB including silkscreen markings where some interesting information can be extracted. This is really interesting to look at Raspberry Pi from different perspective and learn something interesting on how ingenious engineering has been involved here.

3 Weird and Wonderful Raspberry Pi Innovations

The Raspberry Pi is one of the most acclaimed inventions of our days – a credit card sized computer with the potential to improve our lives in an incredible variety of ways, and educate a whole new generation of hardware and software engineers. In honor of the recent Pi Day (March 14th, or 3/14) and the recent launch of Raspberry Pi 2, here are five of the most interesting (and sometimes weird) innovations we could find that were built using the microcomputer of the future (strong enough, but hopefully not used to play awesome slots at Platinum Play).

1. Picrowave by Nathan Broadbent

According to his website, Made by Nathan, the web and mobile developer Nathan Broadbent first thought of a smarter microwave after reading a post on Reddit about how food should come with QR codes that tells the microwave what to do with them. He built a better microwave using the Raspberry Pi, with better sounds and a redesigned keypad, automatically updated clock – with voice commands, a bar code scanner, and the possibility to control it remotely using a smartphone. Continue reading

Comparing GPIO speed between Raspberry Pi 1 and 2

Raspberry Pi version 2 has changed playing rules between Linux boards. With raspberry Pi 2 here came faster CPU with four cores, RAM jumped to 1GB, so naturally we would expect faster speeds everywhere including GPIO. Joonas have ran several benchmarks to show the increase in numerical values, so we could make conclusions.


He run several common tests with available software libraries and GPIO access methods. Results actually look very promising as for almost all methods speed increased twice and more. For instance Python Rpi.GPIO based raw speed increased from 70kHz to 243kHz. Shell command driven IO became also 2.5 times faster. So this is great news for everyone who was struggling to the limits. For more info and benchmark tests go to GitHub.