By three lug dc plug I assume you mean something like a 2.1mm type dc socket. There are plenty of sites that can show you how this should be done, but this is how I do it. Using the continuity setting on your multi-meter find which pin is connected to the centre pin of the socket. I have labeled this 1 in the photo attached. Connect this pin to the ground of the circuit, the screen of one of the input/output jacks will do if you don't have a spare pad on the circuit board. Test the continuity of the two remaining pins, when no plug is inserted there should be continuity between these pins. Now insert a plug into the socket, test which pin has continuity with the outer sleeve of the plug. This pin will be the positive inlet from the DC adaptor and should be connected to the +ve connection on the circuit, and possibly the ON/OFF led if you have included one. The remaining pin should now have no continuity with any of the other pins when a plug is inserted into the socket. We will connect the positive side of the battery clip to this pin. By using this pin the battery is disconnected from the circuit when a DC plug is inserted. Finally connect the negative side of the battery to the ring connection of your input jack (this is why you should use a stereo jack for at least the input), this will disconnect the battery when no jack is in the socket. Please note this is how to wire a centre negative socket, this configuration is suitable for most pedals and is the normal way of doing it. However some pedals, PNP fuzz boxes for instance work better centre positive. ALSO CHECK THE POLARITY OF YOUR DC ADAPTOR BEFORE YOU BEGIN.

Thanks for the flattering comments. I have never built a loop pedal, to be fair I don't think that it is possible to easily build a digital looper. You will notice that all off the FX in the slide show are analogue (i prefer a classic sound) this means that they are built from easy to source discrete components. A fully fledged looper would need to be digital, and just the startup cost would blow your $200. For short loops I use a Marshall digital delay with a Tap tempo switch (which cost less than £50) although you may find it limited with only 4 second of delay. On the other hand many people have modified tape recorders to produce a WEM/Watkins copycat like echo or loop. Just google homemade tape echo. I can only recommend rolling your own FX, learning to solder is not a great hassle there (like any manual skill once you learn, practice turns it into muscle memory) are many good howto guides on the net. The most difficult step in building a pedal like this is etching and drilling the PCB and even that is not so difficult. I will add a list of useful links to the slide show I think.

In my opinion (sorry if this a bit blunt) If your are as you say noob (remember though everyone is a noob once) programmer I would say this would be quite a stretch, it would be much quicker start from scratch. If you were a L33t hax0r it would still be not the best approach, but perhaps do-able. Dependent on the model you could write a plug-in for rockboxthat might add a basic functionality. However due to the limitations of the hardware and form factor I would say that it could never amount to much more than a toy. BTY I have a E280v1 (Rockboxed) and know how sweet they are.

If you truly want build a custom looper I would start of like this ADC<Micro controller (custom firmware, the fun bit)<Buffer memory<Micro controller<DAC. It probably is quite possible however I would think it be much quicker (even if you have to save up for 6 months) and easier to lash out 250 squid on a Jam Man or Line 6 unit. Not as satisfying I grant you but would end up with a road worthy bit of kit and a lot of free time to make some other killer bit of kit.

Firstly I am not a professional pedal builder, I do try and make my pedals look professionally done however.

Your distortion pedal there are two things that spring to mind, I am sure that you have checked your work and there are no dry (solder) joints present. I will answer to be polite but really your question should be to the maker of the first instructable which I think was this one.

1) Sorry if this sound obvious, but have you tried a new battery. Old batteries often change the sound of a distortion pedal. This is due to the increased self resistance as much as the lower voltage.

2) That the design of the pedal is not a great one. The LM386 chip is one chip power amp not an op amp which is really what you want (a 741 chip or 4558), It will distort an amp for sure but can also put out enough level to power a speaker in its own right. I would suggest that you find a datasheet for the chip and put a 10 micro farad capacitor (30v or so) in series with a 2 k Log pot between pins 1 and 8 to give you a gain control.
The circuit in the instructable seems a less advanced version of this.

3) Try a different circuit I would suggest a similarly simple such as this.

I have generally found home built FX to be as reliable as any shop bought one and have the added advantage that you can tweak them to sound even better.

I have just posted a short instuctable, showing how I finish most of my cases. it can be found here

On the whole these are mainly std cases from Hammond (eddystone in the UK) and the like, its the finish that takes the time You can get the alumminium die cast boxes fromthe below links

http://www.rapidonline.com/Tools-Fasteners-Production-Equipment/Cases/Metal-Cases/Shallow-lid-aluminium-enclosures/71713
http://www.musikding.de/index.php/cat/c169_Aluminium-diecast-enclosures.html
http://www.smallbearelec.com/Categories.bok?category=Enclosures
http://www.digikey.com/

The finish on most of my stomp boxes is just car spray (celloulose/acrylic) with a good sanding and clear finish. The lables are waterslide transfers printed on an inkjet, you can get special paper for this. One of the TS808's has an etched finish , there should be some good tutorials on the web, if not this site.