Today, I spent a bit of time cleaning out the hot end of my Sumpod 3d printer. I put everything back together making sure I was really pushing home the PTFE tube. Unfortunately prints are still messed up by intermittent jamming. I wondered if perhaps the jamming was corresponding to the natural temperature oscillations of the heating process. I did several prints at different temperatures (195’C, 200’C and 205’C) and videoed the process with the temperature reading visible on the LCD.

My Sumpod 3d printer arrived a while ago but it has taken me this long to paint (sand, paint again, sand again, …) the MDF. I finished most of the build last weekend. Since then, I’ve been attempting to calibrate it in any spare moment. After initial problems with the extruder and with the X axis belt being too loose, it does feel like I’m making progress. This print started quite well:

A month or so ago I bought Tracy a Silhouette Cameo cutter as an early Christmas present. Today she made some ‘Dad’ gift tags for my Christmas presents from my two lovely boys, so I thought I’d have a go at making some tags for her presents too. I think they came out quite well considering it was pretty much my first attempt at using inkscape and that we were using the robocut software rather than the official windows-only software.

I recently read a blog post about people “figuring out iphone unlock codes just by looking at marks on the screen” and it made me wonder about my work laptop keyboard. It looks like this (click for high res version): It was new when I got it but it is showing signs of age now. How old do you think it is? What can you tell about me just by looking at my keyboard?

I was planning to answer a question in a comment on previous post and wanted to talk about the number of xPL clients that I have running. Rather than just quoting the number, I thought I’d make a post to put my response in context. Most of my xPL components support the hbeat schema. So I can identify them by sending a hbeat.request message. My perl xpl-sender command can do this:

In my previous post, I mentioned some of the issues I was experiencing with my current choice of home automation protocol, xPL. The primary issue was the need to perform filtering for every message on every client due to the use of broadcasts for messaging. One way to avoid this is to use a pub/sub messaging system instead. A number of people that I respect have been using the MQTT Protocol so I thought I’d take a better look at it.

I’ve been using the xPL Protocol since 2005, prior to that I was using Jabber (or XMPP as it is known now). As I’m thinking about changing protocol, I thought I’d write a bit about xPL and, in later posts, something about the candidates to replace it. The xPL Protocol has three types of messages: commands (xpl-cmnd), triggers (xpl-trig) and status (xpl-stat). They have the same simple format consisting of the message type, common “header” fields, the schema type and schema-specific “body” fields.

In the previous post, I described two of the three significant X10 problems we had when setting up our home automation system. This post will cover the third problem, latency. Although all our lights have conventional switches (well, momentary switches in conventional locations), we use a lot of X10 RF Remotes and X10 Motion Sensors to trigger lights and other devices. Initially, we used a TM13U RF Transceiver Module that receives the X10 RF signals and converts them in to X10 powerline signals.

I’ve written two posts about some of my favourite home automation features and both happened to use X10. So, I thought I should probably mention the significant problems we had with X10 and how we solved them. We had three significant problems. The first was noisy devices preventing the X10 powerline signals reaching some parts of our house. Initially, we attempted to resolve the noise problems by using X10 FM10 Plug in Filter Modules or X10 FD10 DIN-mounted Filter Modules.

Lighting is an important aspect of our automated home. Most of our lights are controlled via either X10 DIN-mounted Lamp Modules or X10 DIN-mounted Appliance Modules. (Some are RGB LED lamps but I’ll cover them in a later post.) Although I am a morning person, I still need a little help waking up in the morning. My lovely children help a bit but being able to have the lights gradually brighten to full brightness when it is time to get up helps a lot, particularly in the winter.