This post describes my DIY wireless solar powered temperature and humidity sensor network, which I have installed in my apartment. Everybody can buy a cheap solar powered weather station, but I wanted to build it myself and learn a thing or two about electronics in the process. read more...
I have just finished my new Arduino library for 433 MHz AM radio modules with a focus on reliable one-way communication and forward error correction. There already are a few libraries that work with these cheap little modules, namely VirtualWire and its successor RadioHead as well as rc-switch, but I wasn't quite happy with either of them. read more...
I have just spent several hours debugging a very annoying issue with the Arduino Pro Minis Watchdog timer, until I finally realized that the fault wasn't in my code, but in the bootloader. The Watchdog timer is used to reset the microcontroller, if it is non-reactive for a certain period of time. The microcontroller can crash or enter an infinite loop for any number of reasons, so an automatic recovery from these states is an important feature. read more...
Pulse-width modulation can be used by a microcontroller to control the power supplied to other devices like LEDs or motors. It works by switching a digital pin on and off at a high frequency. The power supplied to the device is determined by the length of time the pin is on versus off. This relation is given as a percentage and is called the duty cycle. read more...
If you try to use the popular, open-hardware ISP programmer USBasp in Linux as a regular non-privileged user, you get an error message like this:
avrdude: Warning: cannot open USB device: Permission denied
avrdude: error: could not find USB device with vid=0x16c0 pid=0x5dc vendor='www.fischl.de' product='USBasp'Yesterday I decided to do a little project with my cheap Arduino Pro Mini clone, which had been lying around for a while. I decided to power it with normal AA batteries and I assumed that this tiny board would already use the minimal possible amount of power. But I soon discovered that it had an annoyingly bright power LED, which couldn't be turned off. While searching for a solution, I came across lots of articles and posts with catchy titles like "How to run an Arduino (clone) on (AA) batteries for over a year", but I couldn't find a step by step guide for a total beginner like me. Since my Arduino clone had cost me only 7 €, I decided to warm up my soldering iron and start messing with it. read more...