Homebrew PCBs

A few of you might know i use bicycle valves with the valve ball or hose  
removed in lids on solvent bottles and other stuff that does not mind  
contacting metal, like this:
<http://tinypic.com/rs63ur.jpg>
This is great because it allows you to take out tiny amount without  
obstructing the large opening with something like a rag, which  
contaminates all the solvent if you use a oily or dirty rag. It has one  
disadvantage though, the little black plastic caps just love to get  
misplaced, and you need to remove them beforehand, and replace afterwards.

Yesterday i had an idea how to solve this problem. I was looking at  
commercial dispensers with valves (at least $30 a piece an more). After a  
bit of thinking (passing by the "pull to open" valves on drink bottles and  
detergents finding them unsuitable) i finally found a solution that seems  
to work great. I took a car tire valve, and removed all the rubber on the  
outside, and cut a few mm off the threads on the tip (remove valve insert  
first). Then the valve insert is replaced and the tiny plunger to open the  
valve now sticks out a few mm. Mount in cap like this:
<http://i1.tinypic.com/rs62c5.jpg>

Now if you hold the bottle upside down, and touch the plunger against a  
rag, or a surface you want to clean, or the inside of a countainer in  
which you want to put some solvent, it will open the valve and let out  
some solvent. The little spring in the valve will keep it closed at all  
other times.

I haven't had much experience with it yet, but it sure seems to work great  
and ideal for my purpose. The only danger is if the bottle topples over  
the plunger might come to rest against something causing a leak. If you  
fear that you can lightly screw on a valve cap during storage (so that it  
doesn't depress the plunger of course). I hope the small seal inside the  
valve will be OK with the solvents i plan to use it for.


Anyway, i have spent lots of time thinking about how to solve this  
problem, and i thought some of you might be having the same problem with  
the large openings in solvent bottles, so i thought i better share the  
idea.


ST

Hi all,

I'm new to PCB design and home made boards. I am planning to use the 
photo etching technique using transparants printed with a high quality 
inktjet printer (Canon IPX5200R). I was looking on the web for a test 
pattern to try out etching for the first time, but couldn't find any. 
Using Eagle 4.15 I've created one myself. The idea is I've copied the 
same pattern 10 times and will expose each part for a longer time (e.g. 
every 20 seconds, from 3 minutes on or so) by uncovering it during the 
photo phase. The goal is to test both the printer resolution and the 
etching technique to find out exposure times and limitations regarding 
track/spacing widths.

As I have very little experience in creating PCB's I've taken a shot at 
what the test pattern looks like. I've included a PNG image of it, but 
can provide the .brd file to is anyone cares. Now my question is whether 
this board looks any good for my goals. The track widths I've used are 
0.1, 0.15, and 0.2 mm; the spacings are also those values. The isolation 
of the polygon is 0.25mm and the drill holes are 0.6 and 0.8mm. I also 
added SO8 package and 0402 till 1206 SMD packages. Am I missing some 
frequently used patterns that I should test to?

Thanks in advance for you comments,

Ronald Vanschoren


[Non-text portions of this message have been removed]

--- In Homebrew_PCBs@yahoogroups.com, Ronald Vanschoren 
<ronald.vanschoren@...> wrote:
>
<snip>
>

You may want to post your file to the 'Files' section of the group. 
Those of us who read posts on the web don't see attachments; they're 
stripped before the message is posted. (For that matter, I don't know 
if people who receive email digests get attachments either.)


Regards, Bob

Appearantly it doesn't show up in mail digest either. Didn't know about 
that, cause it works on another Yahoo Group I'm in.
But anyways, I posted a picture on the group under the PhotoEtching 
directory -> Testboard.png

I already found out spacing must be at least 0.2mm or it won't come out 
of the printer well.on glossy paper, must check again on transparant slides.


greetings,

Ronald

Bob_xyz wrote:

>--- In Homebrew_PCBs@yahoogroups.com, Ronald Vanschoren 
><ronald.vanschoren@...> wrote:
>  
>
><snip>
>  
>
>
>You may want to post your file to the 'Files' section of the group. 
>Those of us who read posts on the web don't see attachments; they're 
>stripped before the message is posted. (For that matter, I don't know 
>if people who receive email digests get attachments either.)
>
>
>Regards, Bob
>
>
>
>
>
>
>Be sure to visit the group home and check for new Links, Files, and Photos:
>http://groups.yahoo.com/group/Homebrew_PCBs
>
>If Files or Photos are running short of space, post them here:
>http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
>Yahoo! Groups Links
>
>
>
> 
>
>
>
>  
>

On Sun, 19 Mar 2006 21:37:27 +0100, Ronald Vanschoren  
<ronald.vanschoren@...> wrote:

> Appearantly it doesn't show up in mail digest either. Didn't know about
>
> that, cause it works on another Yahoo Group I'm in.
>
> But anyways, I posted a picture on the group under the PhotoEtching
>
> directory -> Testboard.png
>
>
> I already found out spacing must be at least 0.2mm or it won't come out
>
> of the printer well.on glossy paper, must check again on transparant  
> slides.
>
>
>
> greetings,
>
>
> Ronald


Ronald,

you might want to calculate the width and spacing steps to occur at full  
steps of printer resolution.
For example a 300DPI printer will have a dot size of 3.33mil. I usually  
use 6.66mil as the minimum i can easily make on a 600dpi printer, with  
toner transfer, so that might be different for you.

Otherwise your test pattern is just fine, linewidth and spacing tests, in  
both directions and 45degree, and a ground plane test, all there.
I also usually add some different size text to see how small i can go.

For toner transfer it can be useful to draw a line of known width, and  
where it ends immediately start a "gap" test where the gap is the same  
with as that line. This shows you nicely if, and how much, the lines widen  
due to toner spreading.

ST