Mirroring the ExpressPCB print out

ExpressPCB is a free and easy to learn PCB drawing cad software for hobbyist, many simple circuit application do not required complicated software such as protel PCB, primarily because numerical control automation make use of gerber file is not required.

But the problem for many user that want to make their own simple PCB is that they need a mirror print out to properly done with iron on transfer or photo resist, the printed side need to be in contact with the circuit board to achieve the best result, especially when using a transparency as photo resist, closer contact possible will make fine line as there are very limited gap for scattered light beam.

The print out can in fact be mirrored by printer setting if you do have one of this option in your printer preference. But if you don't have one, you can make use of the Windows XPS Document Writer, I found out that it was pretty easy to mirror XML drawing script. It describe exactly the pattern of the print out by script not pixel, up to capability of 600dpi.

1. Print the layer you want out by choosing Windows XPS Document Writer as your printer, mind the paper size you choose, A4 is by default, this must be the same as your printer setting for paper size.

2. Rename the print out from .XPS to .zip

3. Extract all file, in the extracted folder look for file 1.fpage in directory drive:\your extracted folder name\Documents\1\Pages\1.fpage

4. Mirror all the value of x coordinate in the file, that will mirror the entire print out. Example:

FixedPage Width="816" Height="1056".....
Path Data="F1 M 302.4,436.8 L 513.6,436.8 513.6,619.2 302.4,619.2 z"  Fill="#ff000000" /

The path data describe a filled rectangle, 302.4, 436.8 is coordinate as (x,y), just modify (can be done with computer program) all x such that:

newX = Width - oldX

The scripts will look like this after modified:
Path Data="F1 M 513.6,436.8 L 302.8,436.8 302.8,619.2 513.6,619.2 z"  Fill="#ff000000" /

Basically XML drawing script use to describe those simple image is just line and rectangle, round pad is describe as a line in revolution, all it need is just coordinate information to describe where to draw the item.

5. Rezip the extracted folder with modified contain back to .zip and rename it back to .xps, I found out that rezip using winzip won't work, right click add a new zip file and drag everything into the zip file do work very well indeed.

6.Open the modified .xps file with xps viewer or internet explorer, at the menu click print and you will have a mirrored image print out.

Alternatively this may also work with Microsoft Word image writer, but the procedure may be different or easier.

4-Pin to 3-Pin CPU Fan V2.0

I have written an blog entry about a heat sink fan unit that come with 3 pin fan where there are 4 pin connector on the motherboard, here.

I have replaced two stop working casing fans to new quality fans, previous casing fans die of lack of grease and rusted. But the new fans is noisy too, so I decided to tie the new casing fans to CPU PWM control.

Picture below show the signal from PWM pin-out of CPU fan socket:

It is ~23.5kHz control signal. Sometime, it take forever to hesitate but it only take one day to complete a not so difficult task.

I know the components used is overkill and not having optimized rating, especially the 100uH 2A inductor, fan won't required 2A, at 23.5kHz 5V output all it need is ~300uH 0.5A, but that is what I have in my hand currently. Without the inductor+capacitor filter, it still work but the rpm signal from fan will be significantly interrupted and there will be some weird reading like 11500 rpm.

Side view of control board showing that it connect to 3 fan. But it only take the rpm signal of CPU fan and feed it back to motherboard.

Integrated graphic

This is some story about integrated graphic processor in north bridge or center processor. Not every day people will think integrated graphic is good and important. Most people will use another PCI-E graphic card to boost 3D graphic performance or video processing, why do we still need to have an integrated graphic?

I once thought that it was a wasteful use of resource to assign more silicon die area for this dumb device, especially when I saw intel integrate those graphic processing unit into their center processor. But I do realize that there is a fact nowadays, graphic card getting more easy to malfunction as the power consumption of it increase over time but their heat sink remain the size of about 2 PCI slot.

I have never seen a CPU malfunction so far, but I do getting few chances to know or witness the malfunctioning of modern graphic card. Therefore I guess modern 3D graphic card required better heat dissipation, such as proper air circulation and more clear space for air, this is what unlikely to occur on most desktop or laptop design.

I experienced a malfunction of a graphic card before, at the moment I really needed the computer to do some important task for me. Thank to the integrated graphic, and fortunately thing was done in time. And I realize, having integrated graphic isn't a bad idea because modern 3D graphic chip just isn't very reliable.

Nokia charger

My nokia phone charge fail suddenly, therefore I cut a USB connector from a faulty USB to mini USB cable and make the modification as in the picture described below, and guess what, it is working!

External hardisk enclosure keep disconnecting

Are you facing problem such that your external hardisk randomly disconnecting or unable to be detected at all?

Very likely this is a cabling issue if you experience this problem since first usage of the external enclosure. Whenever high speed data transfer is done with inappropriate cable, interference between cable can disturb the transmission.

There are three way to solve this:

• Get a properly grounded and shielded USB cable, the interference between wires will be minimized.
• Reduce the length of the USB cable, this will reduce loading effect and keep harmful interference way below significant level, thus reduce the rate of fail transmissions.
• Get a ferrite cable clamp kit and attach it to the USB cable, this will adsorb the EMI high frequency energy in the cable.

In the example here is a faster approach for me, reduce cable length! This is original cable come with VZTEC cheap SATA enclosure I get from SRI Computer at RM20, how come they sell a product that have such an obvious defective in design to average consumers? A picture worth a thousand words, here is two thousand words...

Isn't that easy? Just cut it and join it together! Enjoy a healthy transferring mode that never annoyingly disconnect itself anymore, good luck.

Some facts

Some people like to complain and say refilled battery is expansive, around RM200, while they can get a new battery at around RM230-250. Actually they can request for a lower capacity for cheaper cost.

Let see what they get for a 'new' battery they get it elsewhere:

They are happy because it label 5200mAH! But, do them get 5200mAH? May be not, this is the battery cell they use inside, clearly state 2200, i.e. 4400mAH in total!
Even in the chip inside it state 4400mAH design capacity! Do them get 4400mAH?
May be not! After reload those battery with real 5200mAH cell, it show 5863mAH!!! That mean if the battery info can show 4400mAH, it may actually only have 4000mAH!!! Some battery cell maker overrated their battery cell and the pack manufacturer over-label the capacity of their pack!

This can result in unreal power meter showing can last for 4-5hours while it actually only can do 3hours...

Make some cash while you online

Feature: Work at home/Work from your PC/Extra income

Location: Malaysia resident who can own a Maybank Account

Required: Honest, responsible, must be an enthusiast of forum/facebook/community activity and don't mind promoting laptop battery refill services

Pay: Commission based on effort, negotiable, the sums pay is small but the job is simple

Job Characteristic: Advertising/media, not MLM(multi level marketing), not skim cepat kaya, just for people who really enjoy forum/discussion and want some extra small income such as RM100-200/month.

Contact: Kindly mail to mail.altbattery@gmail.com for any questions/details

UV curable solder mask

Didn't make a homemade PCB for quite long time, nearly forget how to make one correctly. Recently this type of UV curable solder mask seem to get very easily available.

After a few round of failure, finally find out the way to make it work correctly.

This is summary of some tips to make it work:

1. Apply only thin layer of paint, excessive paint will cause the paint underneath have difficulty to cure and the paint may become easily peeled off during removing the transparency.
2. Preheat the PCB, release moisture or gas absorbed by the board, or else it can cause bubble during soldering, I preheat it with a laminator.
3. Cure long enough time under UV, the period is depending on UV light strength, 1 hours is normally more than enough and cured.
4. Reheat after exposure, this will strengthen the paint.
5. The UV curable paint doesn't seem to survive high temperature, solder only with ~250-300 degree Celsius.
6. This solder mask have some conductivity, which is not a good thing to know, long trace should not be too close, or else please consider few mega-ohm shorted circuit which may affect some high precision circuit such as high gain op-amp or delta-sigma ADC.