Water softener level detector

In places where water contains higher concentration of dissolved minerals is considered to be hard ware. It does not affect human health, but teapots, washing machines and dishwashers suffer from calcification. To avoid this problem, there are water softeners used where special salt is used to soften water. Of course this salt also dissolves and needs to be refilled time to time. David always forget to refill the tank because there is no visual indicator of it. So what you don’t see – you don’t care. To avoid future conflicts with his wife, he decided to add visual indicator to water softener. On front panel he mounted LED bar graph where salt level is displayed. Also he added photocell to detect room light. It simply detect if someone is in… Continue reading

Interfacing MQ-3 Alcohol Gas Sensor to Arduino

Today’s electronics allows doing many things, you wouldn’t dare to imagine few years ago. Most of sensors became compact and cheap, so every hobbyist can make wonderful and practical things on a low budget. Playing around with Alcohol Gas sensor sounds really interesting as it has some practical use… we all know what is this about, isn’t it? Sensor itself is very simple to connect – it requires one ADC input of Arduino, and depending on amount of Alcohol Gas in your breath output voltage changes that can be interpreted in ether way like in this case with bar of 10 LEDs. This is very simple and inaccurate way and only may fit for parties to make drinking more fun (if it can be considered a fun thing).  Ok, now… Continue reading

Control 101 LED bar-graph display with AVR

Thomas Scherrer has described his experiments with bargaph display that consist of 101 LED. Because HDSP8820 LED display has specially 10×10 multiplexed LED structure there are only 20 AVR microcontroller pins needed. And of course 1 additional pin if 101th overload LED is needed. You can download and watch the video of simple demo application, or grab WinAVR source files and build one for yourself. Continue reading

AVR Tiny G-force metter

While stumbling around Hackaday projects I found this interesting G-Force measuring project. Project aim was to measure lateral acceleration force of driver in car when turns when he turns right. According to author car can normally handle 0.8g of centrifugal force. Above this value car may slide to the sideways. Well this of course is a matter of tires used and other factors.     Measuring board contains: Atmel ATtiny26 microcontroller; 3×10 LED bars; ADXL103 accelerometer; and other necessary parts needed for correct performance. Program reads accelerometer value via ADC converter and indicates on one of 30 LEDs on the bars. There is simple lookup table implemented which corresponds to 1g(left) on first LED and 1g(right) on LED 30. The middle LED indicates the current G-force. Design can be improved… Continue reading