AMIGA alive

AMIGA alive

Saturday, October 17, 2020

Amiga Art Contest 2020: A tiger and a mouse on a tablet

Having invested some time on getting a graphics tablet running, and equipped with a now 68040@40MHz driven Amiga, the deadline of the Amiga Art Contest 2020 by Douglas from 10 Minute Amiga Retro Cast (10MARC) and Pixel Vixen popped up somewhere, and pretty much from out of nowhere I started painting...

The graphics tablet is a "Lifetec" branded Tevion/Aldi LT 9310, powered by a homegrown floppy-port-PSU, and connected to the Amiga 1200's internal serial port at 19200 baud and 200lpi, using FormAldiHyd driver from AmiNet.

FormAldiHyd requires MUI, which makes it look a bit nicer than if GadToolsBox had been used, and probably saves the author some typing, but ultimately it's an unneccessary dependency. Anyway, FormAldiHyd hooks into AmigsOS's input handler system, thus is more or less application independent.

PersonalPaint 7 was chosen as the paint program - it's quite fast, straightforward, and system friendly. Basically what I wanted is just some software that's able to properly set pixels on screen according to my hand's movements. 640x512 hires interlaced is my preferred screenmode, and you cannot be more Amiga than a 32 color picture - this will be the artwork's geometry.

Work-in-progress, using graphics tablet and mouse

The tablet works! But over hours of painting it turns out you need some strong nerves to keep going despite all the hiccups. Practice makes a huge difference, once you get an intuitive idea about the graphics tablet's dimensions and haptics - both it's overall physical features, and it's drawing area - and the speed the system is able to handle, you can make really good progress, but the tablet becomes unresponsive from time to time, or stutters badly - resulting in interruptions in workflow, and sometimes random dots and lines in the drawing area. (PersonalPaint's multi-undo is very helpful here.) I wasn't able to identify the bottleneck, experimented with FormAldiHyd's settings, New8n1.device as a replacement for AmigaOS's serial port driver, etc. Most times just touching (moving) the mouse would re-enable graphics tablet input, but at some point I kind of gave up and would keep using the mouse for a couple of minutes for painting, then give the tablet another try.

The tablet is still amazing fun to use, and moving a pen is incredibly much faster and smoother than moving a computer mouse with your entire arm. This may affect the results: I ended up using a drawing tool other than pen/airbrush only for the peace symbol, everything else you see in the final result is hand and finger movement. (Ok, maybe the tiger's eye was flooded.)

After three days of occasional painting sessions, I thought from here on it might get worse, so I stopped. When doodling around the first concept that came to my mind was something with a dog - as you can see it turned into a tiger-dog. I had some horror themed ideas, like a Hound of the Baskervilles or so, but then some positive vibe won't do any harm, and the little mouse was created.

'Nuff said - here's the picture:

The final result, as submitted to the Amiga Art Contest 2020

A lot of amazing pictures (and MODs), have been submitted to the Amiga Art Contest 2020, showing there's no shortage of creativity in the community. Tiger and mouse are very proud to be among the contestants. Thanks, 10MARC, Pixel Vixen, and all artists and judges! 

Head over to...

https://www.amigaartwork.com

 ...to see the rest of images!

Watch 10MARC's Amiga Art Contest 2020 presentation and results video (live-streamed on 2020-10-17, 15:00h):


https://www.youtube.com/watch?v=rR7PE1uFfiI

Make sure you visit "10 Minute Amiga Retro Cast" website...

http://www.10marc.com

...check out their facebook page...

https://www.facebook.com/10MinuteAmigaRetroCast

...and keep an eye on their YouTube channel:

https://www.youtube.com/c/10MinuteAmigaRetroCast/

Follow Pixel Vixen via twitter at:

https://twitter.com/lapixelvixen

Wednesday, October 7, 2020

New Apollo 1240/40 cooling system

My "Frankenstein" Apollo 1240 accelerator needed some decent cooling, so I built something.

The ACT Apollo 1240 is a great accelerator for the A1200, but it requires some extra care. Among the quirks and issues owners of an Amiga 1200 with 68040 or 68060 accelerator have to deal with is heat, especially when using higher- or overclocked CPUs, in a desktop computer case, and when there's no manufacturer supplied cooling mechanism available. The 68040 CPU present on this specimen of the ACT Apollo, with a 80Mhz oscillator, gets unpleasantly hot, so it is likely to become unstable, wear out, and/or damage other components.

To provide some improved cooling to the CPU, a second heatsink was added next to the first one, where previously a 30x30x7mm fan had been positioned. The fan would now require a case and air duct that fits the Apollo 1240 plus a potential 3.3V voltage converter for potential 68060 upgrade, inside the Amiga 1200 desktop case, and direct air towards the CPU and heatsinks in a reasonable way.

Blender 3d modeling fan case
Blender 3d modeling fan case

Using Blender I created a 3d model, printed it, refined it, and re-printed it.

(Current) final version in the center



The 3rd incarnation of the model is the (current) final result. The fan more or less rests on three legs inside the case, and has been glued into place with hot glue, sealing off gaps. The case is 3d-printed from PLA at 0.1mm layer height, with spacer sockets on the bottom to leave room for solder and solder pads below, and glued to the Apollo PCB, also using hot glue.

New cooling system with fan, case and heatsinks

First test runs have shown:

a) The cooling effect seems to be pretty strong! From the previous installation with a CPU temperature that's painful to touch ("ouch! burns!"), it went to somewhere hot that still allows sustained finger contact to CPU or heatsink. Certainly a huge improvement.

b) The noise level is easily tolerable. The fan motor is quite audible at times, but there's comparably little hissing from the air moving through the plastic case. Maybe this can be improved further with a more elaborate shape of the case / air duct.

c) Hot glue is awful because it's somehow neither fish nor flesh, but it's easily removable and makes a very good seal for small gaps in plastic parts. The Apollo 1240 has very few features for extra parts to be be attached to, the CPU might get too hot for direct contact with PLA. Applying and removing hot glue worked very well - at least for development.

b) Overall height, and some space restrictions, are at the borderline. An extra millimeter here and there would be nice - maybe a little cutting and scratching will do, or it's just Amiga case inconsistencies. Otherwise the fan case 3d model might need some modification.

It kind of looks like a mech...
Room has been left for the 68060 voltage converter, but a SCSI connector or second SIMM socket probably won't fit anymore.

One of the heatsinks was already there, so the other one got cut for the 68060 voltage converter "jumpers",
red
(left of CPU) and white wires are repairs by previous owner

I'll see how the PLA takes the temperature, and if the system remains stable in the long term and under heavy use. Also time will show if hitting the Amiga's keyboard above the cooling system and Apollo board will affect the installation. I guess with lots of warm air around, the new fan case will deform if there's mechanical pressure from one of the other computer components applied to it.

For now I consider it a success, entering "real-life" testing stage - 68040 power at 40Mhz, plus there's a chance this new cooling system will allow a 68060 to be installed on the board. :-)

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