my custom wireless electricity meter:
While renewing my distribution board the land lord decided to remove the electricity meter. Now I can't note how much electricity I am using. So I decided to build and install my own electricity meter: the spark counter.
Using a cheap power meter (i.e. peacefair PZEM-004), a microcontroller (i.e. Arduino Nano 3.0), radio transceivers (i.e. nordic nRF24L01+), a single board computer (i.e. Raspberry Pi), and some storage and visualization tools (i.e. influxDB and grafana) I am now able to measure, log, and monitor my electricity consumption.
building an ambient light for the screen:
The CuVoodoo ScreenLight mimics the Philips ambient lighting. The idea is to have LEDs on the back of the screen, lighting on the sides the same color as the border on the screen, creating an ambient light.
To implement this I used: VLC (with the AtmoLight video filter) or boblight (way better) to output over serial the colors to be shown on the LEDs; an Atmel ATmega328P microcontroller at 16 MHz (i.e. Arduino Nano 3.0) to control the LEDs and show the values received over serial; a strips of WS2812B chained LEDs (i.e. BlinkyTape), individually controlled using a data line.
reversing washing machine payment cards:
To use the washing machines in my apartment complex you need to pay using a rechargeable contact card.
I was curious to find out how it works. It turns out it's an I²C EEPROM in a card.
By recording the communication between the card and the machine I figured out where and how the credit value is stored.
Now I can read and write the value on cards using a Raspberry Pi or simple micro-controller, but also program my own cards to work with the machines.
building an electronic cat repeller to guard the fridge:
My sneaky cat can open all doors, even the fridge door. No meat is safe any more.
To prevent that I built a cat repeller using an Atmel ATmega328P Arduino Nano 3.0 board.
An HC-SR501 PIR motion detector checks if the cat is nearby. Then an E18-D80NK range detector verifies if the cat is in front of the fridge.
If this is the case a ~24 kHz PWM signal will generate an ultrasound using a piezoelectric diaphragm, encouraging the cat to leave the premisses.
If it still opens the fridge, a human audible alarm will sound until it is closed.