1 year old but not forgotten
Thursday, April 8th 2010, 04:30:44 pm
Yes, I know it has been a looong while...
I have been so busy with my projects that I did not find the time to document them all on the web.
Well, I want to change this and update my blog more frequently.... Starting .... NOW!
I will be adding an rss link, enabling comments and adding sections, searches, tags, and a lot more really soon.
Before I do all that (or maybe at the same time), I will be adding some posts on the fantastic projects I made/tried during the last year, such as:
We will have all that and probably more in the incoming weeks.
LM3886 or the search for a footprint
Monday, May 25th 2009, 09:37:22 am
Chip-amps have become more popular recently due to the sudden interest generated in the HI-FI and the audiophile domains by the (now famous) gainclone amplifiers. The concept of the gainclone is pretty simple: you put together a simple power supply to power up a nice big fat op-amp. This design is the perfect easy project for hobbyists looking for week-end projects, since it has a very small parts count. And to top it off, the result is usually quite impressive!
- A 3-axis CNC machine made of wood. The cnc does wood, metal, plastic and ... pcbs. Engraving, cutting, drilling and more.
- Plans of my newest speaker designs.
- Some thoughts on the latest linux distribution.
- My ongoing efforts to create a g-code exporter for PCB (the linux EDA software).
- A couple of simple, yet unique circuits.
- Some metal folding attempts.
- And a much needed update on my completed gainclone amplifier.
There's a lot of kits available from multiple sources, BUT as a true DIYer, where would be the fun in buying a kit when I can do every part of the building process by myself! (And learn a lot at the same time.)
With that in mind, I proceeded to purchase my first pair of LM3886 chips. I looked at my local electronics surplus store for a suitable transformer to power them up on the cheap. The transformer is, obviously, the most expensive part in a gainclone project, since the little chips cost less than $10 each.
After building the power supply on my breadboard, I had 2 options for the chips.
Option 2 was the easy way to go: much simpler and less hurtful for the chips.
- Bend the pins on the chips to make them fit on my breadboard.
- Solder some wires to every pin.
I was able to test and tweak my circuit and enjoy a nice stereo amplifier very quickly. I even made an enclosure for it... out of wood! I did not have the time to make a printed circuit board, only point-to-point wiring, but it still worked!
Nonetheless, I wanted a board for my amplifier. So, I loaded my favorite EDA: PCB (running on Linux, of course!), but realized it did not have a symbol for a TO-220 chip with 11 pins. Therefore, I searched the web for one, but the only thing that came up was a pdf document (found here) explaining how to create footprints for the program.
It's only recently, though, that I took a good look at the document and made my footprint. All the dimensions needed got confusing at one point. I would print my result and find that the pins did not align correctly and that the copper circle for a pin was too small or too big. I did find the right dimensions. (with great help from National Semiconductor's datasheet of the LM3886)
I am now, finally, working on board layouts, and you can do so as well with my TO-220-11 footprint!
Mat's DIY electronics
Monday, May 18th 2009, 05:46:13 am
I have just finished programming this website. I'll post about electronics projects I am doing and those I hope to do really soon.
I'm going to start slowly and add more content on a (hopefully) regular basis.
Hope you'll all enjoy it!