Mat's DIY electronics
Electronics, DIY manufacture, Robotics, Linux, Programming and more.
Home Archive Contact About 1 year old but not forgotten 2010-04-08 16:30:44 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:
  • 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.
We will have all that and probably more in the incoming weeks.
LM3886 or the search for a footprint 2009-05-25 09:37:22 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! 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.
  1. Bend the pins on the chips to make them fit on my breadboard.
  2. Solder some wires to every pin.
Option 2 was the easy way to go: much simpler and less hurtful for the chips. 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. to22011.pngIt'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 2009-05-18 05:46:13 Hi everyone, 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! -Mat.
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