Second Scope Clock

[Grahame Marsh]

Work in progress for a new scope clock. But fully working and complete
to date with schematics, layouts, all source code (GCC-AVR) and a
description of how it works.

http://www.sgitheach.org.uk/scope2.html

Enjoy
Grahame

[Michel]

WOW! Looks like somebody had some fun here! That astronomical face is
a very interesting idea, would be even better if it had a moon rise/
set curve and shape of that day's moon.

Seems it becomes as one of those projects that is never truly
finished :-)

Great work!
Michel



On Nov 13, 9:24 pm, Grahame Marsh <grahame.ma...@googlemail.com>
wrote:

[Grahame Marsh]

Michel

Yep, moonrise, set and phase is on my (long) to do list. I just had the
sun's equations to hand so was quick to put it.

Grahame

[Nick]

Very pretty indeed, as always!

Nice PCBs - how are you doing those? (I know you use Eagle :)

Nick

[Grahame Marsh]

Nick

Manufacturing I assume?

Eagle to laser film using my trusty HPLJ4 printer that's some 30+ years
old.

Photo etch pre-coated FR4 PCB (normally cut from 160 x 100mm from Rapid,
DS or SS as appropraite). For DS boards I print both the board sides on
film, the top is mirror image so the toner will be in contact with the
board, I make an envelope out of the two films just using staples to pin
the film together and hold the PCB in place.

Onto UV box: SS boards just one exposure, DS boards are flipped over
carefully for a second exposure as I only have a single sided UV box.
(occasionally, pull it all apart, remembering this time to remove the
black plastic film from the PCB and start again!)

Develop, etch, drill and clean. The etch tank is heated and has a
bubbler for agitation.

I'm using clear etchant not ferric chloride after an accident that did
not please SHMBO (let's say I had to buy some oxalic acid to clear up
the mess).

To drill I have a cheap pillar drill from Screwfix and can drill down to
0.6mm with TC bits with care, although my normal drill size for
components is 0.8mm.

With care, I can get DS boards to line up to a small fraction of a mm so
rarely have problems with side to side alignment. But then I'm not
doing using very high component densities or narrow/close spaced tracks.

I bought some very small copper rivets from Mega for via connections,
these I push fit and solder. Mega sell a special rivet punch but it
frightfully expensive. Otherwise I use offcuts of wire from trimmed
resistor leads etc. On the DS board I often use pair of vias especially
when linking ground planes or wide power tracks. This means I'm putting
a U shape of wire through from the board top and folding the leads under
the board before soldering both sides. This gives a neat appearance.

I have used the chemical tinning stuff but don't feel the finish is
worth the cost.

Lastly I'll spray the completed board with a clear lacquer if its going
somewhere like the greenhouse or other outdoor application.

I suppose I could put a web page on the technique but its nothing
special. It is a more expensive route than transfering the LJ toner to
the PCB but I've found it gives better, sharper results and to do DS
boards would be more tricky to get side to side alignment (I have done
it by drilling the through the PCB with a small TC bit to create
alignment marks).

Did I answer your question or miss what you wanted?

Grahame

[Adam Jacobs]

Thanks for the timely explanation of your process, I was just about to
head down this road of printing my first single sided boards at home.
Any recommendations for a first timer? I do have a laserjet 4 already.
:) (and a somewhat newer laser printer as well). I have experience in
film developing, so I imagine that parts of this process may be similar.
I'm hoping that if I do mostly surface mount, I can avoid the majority
of the drilling. Is that correct?

-Adam

On 11/13/2012 9:03 AM, Grahame Marsh wrote:
>
> Grahame

[Konstantin]

Hi Grahame,

When you have your final version of Scope clock 2, It would be great for me
to order a few kits or PCB sets, in case you are going to make prof
boards...

Please also let me know if you still have your Pro PCB VFD Approx Clock for
sale.

Best regards, Konstantin
www.kosbo.com

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[John Rehwinkel]

> Any recommendations for a first timer? I do have a laserjet 4 already. :) (and a somewhat newer laser printer as well). I have experience in film developing, so I imagine that parts of this process may be similar.
> I'm hoping that if I do mostly surface mount, I can avoid the majority of the drilling. Is that correct?

Yup, surface mount is wonderful for making boards at home.

Drilling is what really put me off home board making. These days, I just use oshpark.com and batchpcb.com.

- John

[Grahame Marsh]

Adam,

My top dozen tips would be

Make sure the toner density is as high without marks or smears anywhere
else. Small marks that may be acceptable on the printed page can be a
track shorted on a PCB. Look also for the LJ scratching the film, again
they may not notice on the printed page but leave a broken track on the
PCB. Get a thin Staedtler permanent Lumocolor marker which is etchant
resistant and a fraction of the price of a "PCB pen".

Check the printer for errors in the X & Y plane. Print a box which is
say exactly (in the software) 100mm x 100mm and see what size it is when
printed. You may find, say, 99 mm x 102mm or worse. Most PCB software
has a scaling box where you can make corrections to X & Y sizes.
Perhaps not a problem with SS boards but can be a problem with film
alignment for DS boards. Might be a problem with small SMDs.

Do a small board first. Even to the extent of making up some, say, 25mm
x 25mm swatches and testing the whole process through to etching. On
the swatch put a variety of track widths so you can see that they
survive the process and what undercutting you get. These will enable
you to trial different exposure times on the UV box.

DS boards are not hard, a simple start is often just using one side as a
ground plane. Just take care with alignment of the films.

Watch the chemical concentrations - if the developer is too strong it
will strip the photoresist, too weak you don't get a good development

Watch the chemical temperatures developing is cool, say room
temperature. Etchant needs to be hot 50degC.

I strongly recommend clear etch (sodium persulphate based) as against
FeCl3. It is more expensive but pays for itself if you have one
accident. It is a lot, lot less messy.

If you're not using a commercial etch tank (I was given one aimed at
small production and schools) then you can use any plastic container but
keep it well agitated. My brother has a home made etch tank made out of
a plastic box, a fish tank heater and a fish tank bubbler air pump feed
a sparge pipe.

Dispose of the chemicals responsibly (I used to work for the Scottish
Environment Protection Agency so I would have to say this) :)

If you are going to drill holes then use TC bits in a pillar drill - you
won't drill them in a hand held drill. The bits (even recon) are
eye-wateringly expensive so try not to ping them.

Wear glasses - getting chemicals or a TC bit end in the eye is not
recommended (you only have 2 so look after them) (I used to work in the
H&S team of a large chemical company so I would have to say this). I
uses neoprene disposable gloves when handling the chemicals (not
latex). None are particularly dangerous at working concentrations but
they will cause skin damage (and staining in the case of FeCl3).

I take the chemicals, especially the etchant, close to exhaustion, way
beyond what would be a commercial use period and beyond the
manufacturer's shelf life.

If you're in the UK I can tell you who I buy from.

Looks like a long list - perhaps I should write up a webpage...

Grahame

[Grahame Marsh]

Konstantin

Final version? That's way off! I'm having fun with this design/build
but I want to crack using a flyback PSU, I have ideas for brightness
control using PWM, improving the image in other ways and improving the
quality of the chimes. I also want to try other CRTs especially those
with PDA; I bought a long persistence CRT today to see for myself how it
behaves having seen Aaron's clock. Lots to do, at least winter is
arriving and more time is available to play in the workshop...

I'm not going to make a prof board and/or sell kits as I feel that's the
provenance of David Forbes . I might have hacked his design around a
bit but the concept and significant parts of the design and part of the
software (the font) are still his. Also my Eagle licence is not for
profit and limited to 160mm x 100mm and the cost of extending the
licence is rather steep (ok, I could use the free PCB design software
from RS but I'm not that interested really). BUT, if anyone wants them,
I'll make (including drill) a board set at cost but not sell a kit
(there are no components that cannot be sourced in the EU/USA that I
know of).

I still have a few Approx clock boards and VFDs left. The filament
switcher IC and VFD driver chips have gone unobtainium but I have some
of them as well. I have it on my todo list to rewrite the code from the
pay-for Codevision compiler into the free GCC-AVR which will make the
project more accessible for tweaking. Contact me off the list with your
wants for PCB/VFD/chips and I'll find out what my costs were.

Cheers Grahame

[Michel]

>
> Drilling is what really put me off home board making.  These days,
>

> - John

Drilling, vias and time is what put me off. I don't find DS boards
particularly easy to do at home, sure it can be done but it is very
easy to get a 0.5mm error in your film alignment. I could only do the
exposure from one side, so I had to turn the board around. If you can
do both sides at the same time, alignment will be easier to achieve.

When living in Europe, I bought all the stuff from Conrad, boards,
chemicals, tanks, heater elements, exposure frame etc etc. Very cheap
for hobby, can probably buy the whole lot for less than 150 euro and
still have good results.

If you use a Laser printer, go for something 600dpi or better. The
older Lasers were 300dpi and it is usually enough, but I find 600dpi
to work just a bit better. I have also used inkjet printers with good
results, you do need to find the correct film for your ink otherwise
it will smear.

Michel

[Lucky]

Grahame another well thought out device you have there looking great especially like the sunrise/set (and forthcoming moon phase) option.
Great to see you're still busy in the workshop (must contact you soon)
Dave

[threeneurons]

Everybody should have a clock that does Klingon ! Nice !

[Oscilloclock]

Grahame, it was a privilege to preview some of your new clock design a little earlier on - and now I see the site. It really is amazing. I love the fonts and all the different faces you have dreamt up!

And now we have seen experiments with Motorola, PIC, and AVR architectures. It is time for me to start dabbling in C....

Stunning work!

Aaron

[Grahame Marsh]

Aaron

If I can point you towards AVRs, C, GCC-AVR it will make life very easy
for us to swap code and hardware ideas. PIC-AVR wars go on - as far as
I can see (I'm not an electronics engineer, just a hobbyist) you can do
most things with both. I only went down the AVR route because Elektor
(a monthly European electronics mag) published a design of a
experimental card using an AVR which I built. I have a lot more
libraries written which will go up on the web site when I get a chance,
which you can have. I found the learning curve for C and GCC-AVR rather
steep but I can point you at some reference books if you need them. One
thing useful about GCC-AVR is that its free!

Some of the clock faces came from other people otherwise its just a lot
of fun. I'm currently working on a an old style flip clock - an idea
from Alan Flowers in Cork Ireland who has built scope clock 1 and is now
building scope clock 2. See the enclosed video clip, but not finished
yet. I have some more silly fonts to put it, the one I can't get right
yet is the Preditor font (from the film). I also want some more dynamic
clock faces that show off the circle drawing in particular.

I've just bought two long persistance tubes to try out and see for
myself what a difference it makes.

By all means reference my website and/or just poach anything you want
(the animation is just a link to the wiki page so is very easy to use).
Our hardware designs are common enough for you to use at least some of
the description but as you've seen I put a lot of David's TTL into a
single attiny and did a very different circle generator etc.

BTW also I've looked at using 12 bit DAC and I think it is doable. There
is a pin compatible drop in DAC for the one I used so its only software
changes to trial it.

I'm just struggling with flyback transformer equations - currently I
have a primary winding requirement of 0.04 turns which makes me think
I've made a mistake somewhere. If it works I'll have a full description
of designing a nixie/scope flyback convertor.

This morning's job was moving about 3 tonnes of firewood from the drive
where it was tipped to the wood store round the back of the house, Now
I'm knackered. But that's our firewood in for the winter.

Cheers Grahame

[Nick]

You need to do a "Vetinari" clock face (e.g. http://www.youtube.com/watch?v=KHKOhO_-hZY)

Its just soooooooo irritating...

Nick

[Grahame Marsh]

Nick

Thanks for the reminder - I need to add a Vetinari option to each clock that displays seconds.  A Vetenari Elvish or Klingon clock - now that's a genre mix up.

Currently working on a old style flip clock - here changing seconds 58 - 59.



Grahame

[Dennis]

Grahame, this is some really great work your doing here. The displays are super but a flip clock?! That IS nice. Can't wait to see what's next.

---

From: Grahame Marsh <graham...@googlemail.com>
To: neoni...@googlegroups.com
Sent: Wednesday, November 14, 2012 9:10 AM
Subject: Re: [neonixie-l] Second Scope Clock

[Michel]

It is irritating indeed, and at the same time very funny to trick some
visitors.

I wonder if anyone has ever noticed that the clock on a windows
computer is also a bit erratic. If you click the clock next to the
system tray and watch the seconds hand while watching your watch (how
many watches is that in one sentence??) you will notice that the
movement is very erratic, sometimes too slow sometimes too fast. Could
be as much as half a second, just keep an eye on it for a minute. I
checked it with a few computers and they all show this erratic seconds
hand.

Michel


On Nov 15, 3:50 am, Nick <n...@desmith.net> wrote:
> You need to do a "Vetinari" clock face (e.g.http://www.youtube.com/watch?v=KHKOhO_-hZY)

[AntiqueSounds]

This is amazing! I am still just getting into this stuff. I am working on my first learning kits of dekatrons and nixies. Now I am all geeked to get to one of these!   Did I say, wow!? 

:-D

Thank you so much!  If you go work toward formal kit or even a bare-bones PCB with a BOM and the base software (you already did the software and eagle PCB diags here, I know). I can follow directions well. I think I'll get my feet on the ground first and come back to this as soon as I can. It is so wonderful!  Great work!