Author Archives: James

Inkscape and 1980’s plotters

I had a Inkscape itch that needed scratching and as the holidays are upon us Christmas 2014. I found the time to write a patch for Inkscape.

Currently its not easy to use a plotter (DXY-1300) and have it switch pens in Inkscape. There is no method in the GUI to switch the pens. I read on news groups that it would be a good idea to have the stroke colours assigned to pen numbers. I have written this patch that allows pen stroke colour assignment to pen numbers.

screen shot

I used the stroke colour as this the colour the line changes. I also used the primary colours. Until somebody can modify the GUI this was a comprise.


The export as hpgl now appears like so. With the pen assignments to pen numbers. Then the file will be produced with the necessary SP (Select pen) commands. The original Pen box has no function.

There are three files in the archive. They go in the extensions directory. I would also backup your originals first of course. Have fun and let me know if this helped.

These files are based on Inkscape 0.91pre3 However I don’t suspect these hpgl bit are in much flux so it should work for older versions. Mileage may vary.


There a few things that could be improved upon in hpgl_encode. The order in which the pens are selected are based upon the order in which they are drawn in the editor. This is not ideal and to solve it is a “travelling salesman” type problem. This I believe has already been solved in the Inkcut plot extension. So it would be wise to integrate that code.

Here is a test file that will select each pen in order of 1 through to 8. The lines will be drawn from the bottom up. This can be used to test the new pen select code I have added.


An anomaly I noticed was that when selecting a pen the head returns to the same place. then continues drawing with the next command. This makes the pen change look inefficient as the head will return to where is once was, even if there is no line to be drawn. Then moves to the new position. Ideally before and after the Pen select command is executed the head would not return to the same location, but instead go to a new location. This seems to be a feature of the hardware and not something the command sequence automatically does.

It would be possible to have the head go to, a location nearest the next pen section then do a SP (Select Pen) so the head only travels back to this location and appears as if its travelling to a new location after pen selection. This would require eight locations outside the pen cartridges to be defined. This may be different for every plotter however. So unless somebody asks, I can’t see the justification in this one.

Calibration of Gos 658G Oscilloscope

Realising there is no documentation on the internet to calibrate these oscilloscopes.

I have a GOS 653G Or a (ISO-TECH ISR658G) and wanted to calibrate it. Note that powering up the unit will give better calibration results as the CRT warms up and the power supply reach a static voltage. Ensure this is the case before calibration.

Cursors board

Oscilloscope Cursors board Top back

I have identified 5 variable resistors on the cursors board. This is the board that is controlling the cursors drawn on the screen. There are some things one needs to be aware of when trimming these.

1. The cursors need to be at the extremities of the screen as these need to be aligned to the edge of the graticule.

2. These need to be adjusted with caution and in ratio to the zoom variable resistor located near the CRT tube ref.




Today I was not feeling so well, man flue so I vegetating in bed on the net and stumbled across Netflix. I had a free month trial. I had heard that the Microsoft Silverlight is at the sites core and me being on Linux I would have an up hill battle. However, to my surprise it was easy to get this working. I followed the guide for my distribution (gentoo), there are guides for all other popular Linux flavours also for PipeLight

I think most people would ask why bother. I think its a matter of exploring what technologies are being used to deliver particular content. How its being used to maybe “control” users into certain decision that reflect buying decision.

And also to exercise my freedom and to show that large corporations will not encroach on my choice of operating system.

Don’t worry I know what your thinking (This guy uses a tinfoil hat to stop the government reading his thoughts). Not at all. You can either see what I’m getting at or don’t care 🙂 Let me know what you think and maybe give it a go yourself its easier than you think. The last and quite important reason I did it is to have the stability and security of Linux as the basis.


Bristol Synthesiser Emulations on Linux


Boy have I had some fun over Christmas. This years been interesting, in particular, because I have been listening to Portishead specifically, a track called Humming. At first, I thought it was a Theremin that was creating that spooky high pitched sound.  But after watching some videos on facetube I discovered it was a synthesiser. I know those things from the 80’s. I grew up in the 80’s unaware that there was this instrument revolution going on, that died by the late 90’s. These things to me, look like a piece of scientific equipment, I think that was the initial attraction, but with a keyboard stuck on.

I really wanted to see how it would be possible to make such a noise. These things, if you can find one for sale, are quite expensive and rare. Its basically an analogue computer with oscillators, square sawtooth, sinusoidal, etc, if you don’t know what those are then it does not matter anyway, most people just turned the knobs and see what sound came out.

So I was poking around with Google to see what was around in the opensource arena and I came across this. Bristol synthesiser I emerged it on my Gentoo box (windows versions are not available). After a few hours of playing I managed to get a sound that was alike to Portishead Humming with (-mini).
I took a screen shot so you can try it your self.

Have fun.

Macarons 101 (revised 2)


Here is a recepi to make 32 Macarons.

Macarons Ingredents
2 Large Eggs
115g icing sugar
75g ground almonds (for pistachio flavour swap 25g of almonds for 25g of pistachios)
50g Caster sugar
1/2 tea spoon Vanilla extract


To make the Macaron mix the Almonds and icing sugar into a bowl. I sifted them together. Whisk the egg whites into a bowl (Note don’t over whisk) and the Vanilla until soft peaks can be made. Then fold the Almond and icing sugar mix into the egg whites. Pipe out onto a oven tray with grease proofe paper and leave for 30 minutes. When you can just touch them without any sticking to your finger put them in oven 210 degrees C for 10 to 15 minutes. They may go slightly brown then there done, Voir La

Make the butter icing filling

55g butter
1/2 tea spoon Vanilla extract
115g icing sugar
1 tea spoon Vanilla extract

Mix these 3 ingredents into a bowl and then use it to stick between two of the cooked Macrons.

Le Quecumbar and Brasserie

Pub sign

When you see this your there 🙂

I could not help but make a article on the “Le Quecumbar and Brasserie” I visited this week starting at 8:00. On Tuesday they have a Jam night. There is a gentleman called Victor who is the linchpin of the night appropriately playing the Double Bass, and usually 6 or so guitarists from far and wide across London. The quality of musicianship is high. So far I have been twice and I think I recognised 3 previous guitarists. So this tells me the “Gypsy Jazz” genera it still very much alive and thriving.

I also had dinner there which was delightful.

Here are some recordings I made of the evening. I could not catch the names of them all so I would appreciate it if some one could email me with naming them.

All of Me

Clair De lune


Djangos Tiger

Frech Ambiance

If it ain’t got that swing


Troublant Bolero

le quecumbar tue 15th jan3 unknown 1

le quecumbar tue 15th jan3 unknown 2

le quecumbar tue 15th jan3 unknown 3

le quecumbar tue 15th jan3 unknown 4

le quecumbar tue 15th jan3 unknown 5

Bossa Derado

Here some pics of outside.

The Quecumbar and Brasserie is located here.

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