January 2009 – Random jottings of an engineer

Using OpenDMX in Linux

Enttec makes a handy little USB to DMX converter called OpenDMX. (DMX is the standard theatrical lighting control protocol – a serial protocol where up to 512 lights are daisy chained together). Several people have made Linux kernel drivers for this device – for example: the DMX4Linux project and Erwin Rol – however, at the time I got one of these dongles, they either didn’t work with the 2.6.x kernels or required compiling a kernel module (irritating when apt-get keep installing new ones requiring a module recompile…). So, I set about using another approach – using just the stock Linux serial drivers.

Category: Open-source software | 3,114 Comments

January 1

SquidGuard and Polipo

SquidGuard is a high-speed URL filtering programme. It accepts URLs on stdin, matches them against a blacklist (of URLs, domains or regular expressions) and produces re-written URLs on stdout. It is designed to be used with the open-source ‘squid’ HTTP proxy. It’s primary purpose is for restricting access to unsavoury websites.

Polipo is a a fairly lightweight HTTP Proxy server designed for personal use. It is particularly designed to reduce the ill-effects of high-latency internet connections on web-browsing – making use of modern HTTP filters such as HTTP persistent connections, pipelining and cache-control headers.

Getting these to work together…

Though Polipo has support for ‘squid-style redirectors’ it does not work with squidGuard redirector out-of-the-box.

Category: Open-source software | 1 Comment