Saturday, 11 May 2013

Rune Tags

One of the nice things about empire was that groups tried to get some uniformity amongst themselves, our group had brown and mustard clothing on left and right, other groups had little trinkets like this to suggest they were all healers. It's hard to imagine that the next game is only 2 weeks away now, I'm hoping for another flood of orders again :)

Friday, 10 May 2013

Project #24 Mazing 2

I mentioned this briefly before but I tidied it up a lot in time for the maker faire and added a few features to it.

It's a CNC controlled marble in a maze, the X and the Y are belt driven rather than the more common tilt mechanism. The intent was to persuade people to type in a series of simple programming type commands to drive the ball around the maze from the start point to the end point. I'm pretty sure people didn't see it as programming which is probably a good thing as they were too busy having fun with it. I housed the electronics on top of the board so people could see the details, put in a compass and a scale and gaffa taped a hinge so that the whole thing could flip up and people could see the underneath. (svg here)
24 Projects/ 28 weeks

In essence it's a very simple XY control, but to add some programming aspect to it I set up the arduino to understand a very basic language sent over the serial port. 'N10,E10' would move the ball 10 units north, then 10 units east. I went with 10 units for 1 square because then you could also do movements smaller than 1 square. The distance requested was simply scaled by a factor for the number of steps required and then the code loops until the IO lines have been toggled the appropriate number of times.

For a project on such a short time scale you have to use what's at hand. The XY frame is from a 3020 laser cutter spares I had lying around after the laser cutter fire. The stepper motor drivers are big beefy Keling 4030s I had left over from my failed CNC milling machine and surely everyone must have an arduino or two kicking around by now. Magnets from the gauss gun kits and ball bearings from Donkey Kong. In fact the coding took significantly longer than the mechanical design and assembly.

Version 1 of the code featured a very simple parser of the incoming serial string, it only recognised N,S,E,W and only in capitals. After the first day of the maker faire I vowed to make some serious changes to the way it worked and an extra hour of coding on the Sunday morning made a world of difference. The final version of the code accepts upper or lower case, NE,SE,NW,SW for diagonal movements (although NE10, moves north 10 and east 10 which imo is simpler than calculating the hypotenuse and having to type NE14), and some limit checks which count the number of steps made in any direction and stop you from running it into walls. These step counts are also used to return the ball to the start at the end of every run meaning that you have to type a complete string of instructions to achieve the goal.

Even though it's nothing special I thought I'd share the source code too.
I figure this is the optimal route through the maze.

Thursday, 9 May 2013

HPC Service and Tube replacement

HPC laser came over today as my machine has recently experienced a serious drop off in laser performance. They had a quick look around and went to replace the laser tube as planned. Turns out the lens in the end of the tube was pretty well caked in gunk and is likely to be the main cause of failure. This is my mistake for overlooking the end of the laser tube, although the 3060 makes it particularly hard to even see the end of the laser tube let alone get in there to clean it. My laser is pretty dirty anyway and they politely repeated the instruction that I should clean everything more often. There was instant improvement, the settings I was using last night and having to cut twice burnt clean through the plastic today and actually set it on fire.

So why the photo above? Well you know that when you put something back together again there are always a few pieces left over? I pulled the extractor fan apart to clean the impeller and when I put it back together I had all of the above left over. It's a pain in the ass to pull apart and reminds me of those 'ball in a cage' milling exercises, every single screw had to be undone to remove the fan and even with the access panels off you couldn't just release the unit. So when I put it back together I realised that it would fit neatly inside the laser cutter case, everything in that photo is a leftover.. Reusing the internal brackets, screws and ever rubber feet

I managed to rehouse it inside the laser so now instead of churning away on top of the laser at ear height it now sits quietly in a larger case and the reduced amount of ducting means it's even drawing more air through it now. I need to extract the power switch and IEC power point or just wire it straight into the machine (although I still like being able to turn it on and off independent of the laser) but it's already a vast improvement.

Hazel Colleen Raynsford

We had a little baby girl, Hazel Colleen Raynsford, born Friday 3rd May, 9pm at 7lb 6oz. She is doing exceptionally well and we're all settling into a new routine. Obviously things will be a little slower around here for the time being so bear with me. Currently I'm keeping on top of my orders but not my communications so if your email is important it may pay to nudge me after a week.