Savel brain dump in English!

As cellular phones become more wide spread and newly designed notebook computers and other portable information devices continue to be released, batteries are now required to be “very thin” in addition to having a large capacity and being light in weight. Panasonic is one of the first companies in the industry to successfully mass produce lithium polymer batteries. This new technology allows us to make lithium polymer batteries less than 4mm thick, thinner than
ever before!
Laminate exterior allows for a thickness of only 3.6mm
High energy density similar to Li-ion batteries (135 wh/Kg, 280 wh/l)

It WAS USB2.0 flash drive from Transcend. It was faulty from the beginning. Sometime the system freezed during work and after few of such hangings, the device is unrecognisable. As user lost documents of buying it was given to me. It is not working so I opened to see what is inside:

USB flash drive from inside

The small PCB contains one micro-controller from OTi (OTI002168, Ours Technology flash disk controller) and one flash rom from Samsung (K9F1208U0A). It is 64M x 8 Bit NAND Flash Memory with a spare 2,048K. This chip is interesting for some experiments as it uses only 8+9 pins for all address, power and data signaling.

The ROM and The MCPU

The other side is with 12MHz crystal, 2 transistors or stalisators (5->3.3V) and few pasive stuff.

I bought small, but useful tool. Sometimes it is called “dremel”. Small electric bore with various heads to attach. So I decided to test it and to play with my testing plasma TV. The surface of the display is “scratched” with angle grinder. 🙂 So I tested my new polishing heads on it. The protective plastic of the screen is multilayer. The external layer is made of the plastic, next layer is real glass. The angle grinder cut plastic and damaged glass. It is impossible to fix such heavy damage. But who else is playing with angle grinder and plasma TV? So, if you have small scratches, you can fix them.

As I mentioned in previous post, there are some color spots on the screen. So, when I use TV for more than hour, tv gets hot and all color spots disappear. Maybe some thermal instability in electronics.

No new ideas to post in this blog… To many open projects and no outcome from them… Quite cold outside, my horse is a bit wounded and waiting for small cutting and needle-working 🙂
Found old IBM notebook, installed Win98 and inserted SMC wireless network card… No signal found. Maybe my neighbors didn’t use any WIFI (I have 4 start hotel nearby…) …

Ok, ok. Lets talk about welders and TL494. Sometimes it is hard to start arc. Especially if welder is low voltage one. So we must use some sort of the ignitor. In russian sites, I found various schematics- from simple mechanical to complicated. But they are quite powerful and dangerous. I want to build some ignitor by myself.
It will be low power, high frequency and high voltage power supply. Something like ones used in LCD monitors for cold cathode lamps. Original HV supply from LCD is too complex, too sensitive. So I decided to invent bicycle.

Here is my testing boards:

(LCD cold cathode power supply and some selfmade board with TL494 and POWERFULL mosfets)

And after one dead mosfet, change of topology and schematics, first results:

(after some time, 2005.11.20)

Burned holes in paper

I increased frequency to about 200kHz. Replaced MOSFETs to more powerful and faster (CEB603AL). Now device didn’t shock my finger, but burned small hole in the skin (It hurts!). In the image above you can see how it burned holes in simple sheet of paper. There is no need to close circuit- the current goes through parasitic capacitors.

Still there is problems- when powered from 12V, device can work only small time- minute or two. The mosfet is getting hot. I’ll try to put more modern mosfet (95N03?) and increase the frequency…

Electric arc welders are very simple devices. The old design ones 🙂 New design electric welders are quite complicated devices. But if you find in some trash such nice transformer:

High power transformer from big battery charger

You can connect your welding rod to the transformer secondary winding and began your welding jobs. It will be AC welder. But if you have more components, you can build more advanced DC welder. The welding with DC current is more comfortable and welded connections are much stronger and looks more professional.

Connect such schematics:

Diodes are 200A working current, capacitor- high power electrolytic, designed to give high current (the 2.5mm2 wires connecting cap are getting hot!), shunt and ampermeter (75mV voltmeter) is designed to measure high DC current, L is some very big one.

My testing welder look like this:

And here is some test weldings:

This is 200A shunt connected to the output of welder to measure output current.

Nice sparcs!:

This weblog, Lithuanian version, Fauna lovers pages and few other products are running on simple DSL line. Nobody invested big money to the server- we used usual computer trash. And now we need more power, as original celeron processor and IDE disk drive is lagging web. Especially web pages with MySQL. And the chip-set of the mainboard is made by SIS and is full of bugs. I found old original Intel server box. It is old, 1997 made, dual Pentium 2 server. With few SCSI 3 fast disk drives. So, if everything will be working fine, I’ll migrate my web pages to this hardware.

Now we are in testing stage. Here is the image.

Original Intel server and few SCSI hdds

Operating system: Linux Debian