Friday, June 29, 2012

AVR-stick as a temperature logger

I've stumbled recently upon a little gem called AVR-Stick and bought two of them for about 7€ per stick. I also had a thermoregulated fan controller salvaged from a recycled computer. I decided to desolder a thermistor from that controller and put it onto the stick to use it as a USB temperature logger. Stick's ATtiny85 has an internal temperature sensor too but it should be calibrated otherwise its precision is ±10°C. Thermistor that I'm using is equivalent to the NTCLE100E3103JB0 and its resistance is 10K at 25°C. Any other NTC thermistor that has resistance around 10K at room temperature could also be used but it should be checked if manufacturer specifies Steinhart-Hart equation coefficients for it.

Thursday, June 7, 2012

Using of the xfce4-messenger-plugin

I was looking for a way to display an icon on a xfce desktop panel on some event. One possible solution is to use the xfce4-messenger-plugin. The plugin listens to messages on the D-Bus and displays them in a pop-up window or in the panel. Additionally it can display an icon if the message sent is prefixed with a identifier.

Tuesday, June 5, 2012

dnsmasq cache size tuning

dnsmasq is a lightweight DNS forwarder and DHCP server used primarily in embedded systems (like routers) where resources are limited. DNS queries are small in size but latency introduced can be significant depending on the proximity of a DNS server that can answer the query. DNS queries are usually cached either by a web browser of by the operating system but if several clients are connecting to the Internet through a router they would all need to send 'possibly' same DNS requests over again. That's why dnsmasq running on a router has a local cache for DNS queries.

Saturday, June 2, 2012

Mount WebDAV resources with davfs2 and secure it with encfs

Number of online resources offering free remote storage facilities has seriously increased in the recent time and it continue to grow taking a good share from the Dropbox's marketspace. Dropbox has been on the cloud storage market since the early days but for many people a proprietary client offered by Dropbox is not acceptable. There are of course attempts to overcome such a drawback by implementing an open source client that is configurable to use different types of cloud storage facilities transparently to the user. An example for such a client is I've been waiting for the project to reach a mature state for months but it seems like they are not making it in the near future. So I started to look for other possibilities to utilize cloud storage facilities using only standard means available on the operating system's level that would require no dedicated client to be installed. The rest of the article is devoted mainly to users of Unix-like OS's but there is a section in the end explaining how to mount and encrypt WebDAV resources on Windows platform.