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.

Highly configurable and programmable TV box with open source firmware

People who have smart TVs sometimes get disappointed with limited functionality, lag and lack of customization.


TV box in other hand can give much more flexibility and ability to expand feature list. GeekBox has been working on intelligent TV box which features High performance Octa core 64bit ARM Cortex-A53 processor that includes graphics chip capable of producing 4Kx2K video. There are 2GB+16GB eMMC 5.0 memory on board which ensures fast reading and writing speeds. AP6354 WiFi module gives all latest wireless and Bluetooth communication capabilities. TV box comes in modular design where main board is interfaced using MXM3 interface. So it can be used as development board, expansion board or plug-in board for other devices. Box comes with a set of interfaces you can choose: 2 USB, 1 Micro USB, 1 HDMI 2.0, 1 DC In, 1 RJ45 1000M LAN, 1 TF Card Slot, 1 Fan connector, 1 RTC Battery connector, 1 Serial Port, 1 TP interface, 1 Display interface. Continue reading

Looking for digital oscilloscope? – Try DSO138 from Gearbest

We all agree that hobbyist or engineer should have proper bench oscilloscope for everyday use. They have all standard features including built in screen, interchangeable probes and convenient knob controls. Anyway if you are looking for temporary cheap solution, you can try building your own oscilloscope. Luckily you don’t have to make it from scratch because there are many projects and kits available that are cheap but powerful enough to fit most of basic needs.

DSO138_Kit Continue reading

Bringing retro 8080 retro computer on Stellaris Launchpad

Some people have passion on building old gear simulators on modern hardware. Some of you may remember old BASIC machines that run on 8080 processors. If you look at hardware specs – they were really scarce: 1k of user RAM, 1k of display RAM, 8k for BASIC ROM and 2k of monitor ROM. Simply speaking almost any modern microcontroller can house such parameters inside memory and have more than enough of processing power. jscrane have built an emulator for this machine on Stellaris Launchpad.


Launchpad has 16k of RAM which was divided in two parts – 12k for main memory and 2k for the display. It has plenty of flash (256k) where all ROMs can be placed. Simulator supports 30 lines of 40 characters on a display, which is a bit less from original (32×48) but this limitation seems to be on a 240×320 display. There is also an SD drive attached, and PS/2 keyboard. Programs can be loaded from SD card really fast as the programs are limited to 14k. For more info and source files refer to GitHub.