Monday, May 5, 2008

Progress and Setbacks

Yesterday I worked on the electronics and finished a number of components. I finished soldering the 6 limit switches though I only connectorized 2 of them as it is a pain to do without a crimper and mine is currently at one of our clients site. I then attacked the soldering of a PWM board and a stepper driver board. I did the PWM board first and it went great until I realized that I had put a diode in backward. Took me nearly half an hour to figure out how to get the diode out without cutting the leads (since I cut the leads before noticing). One thing I would change on the parts listing tools and BOMs is to have a "buy spares" button or something to order 1 or a few of most of the components so that there is a spare if you manage to ruin a component, I spent alot of time worrying about messing up a single resistor or connector simply because of the pain of having to wait for a single component to come in the mail. The stepper driver was relativley easy to do once I figured out some soldering issues (keep those tips clean!).

Either way, at the end of the day I had a PWM and stepper board all soldered and ready to go but I realized I had left the arduino and power supply at home (I do all soldering at my office). I went home and starting following the instructions for hacking an ATX power supply when I noticed that the wires were not the correct colors. I did some digging around and discovered that since the machine I had cannibalized for the power supply was a Dell, the power supply is a mutant and proprietary offshoot of the ATX standard designed to make upgrading as painful and difficult as possible. I spent a while trying to figure out how to force the power supply to turn on but I couldn't find anything too helpful. I tried plugging in a HDD to simulate a load but that didn't seem to work. So I am going to beg people at the office for an unused power supply and try a standard ATX supply. Until then I can't test my boards to see if they work and i'm hesitant to make another stepper board without checking the one I have now for problems.

Thursday, May 1, 2008

Soldering an Opto-Stop

Got my parts from mouser today. I was kinda worried that it would be a jumbled mess of unlabeled components that would need to be carefully inventoried and organized; couldn't have been more wrong, every component came in a separate bag with bar code and description. I am going to try making an optostop first to see if my hands are steady enough to solder all these components (no coffee in 6 hours). If I am not mistaken I only actually need 3 of the limit switches so these are also probably the best thing to screw up if I am going to ruin something.

Here is my setup:

I am using the build instructions from the Make a "Darwin" pages, linky. First thing I noticed is that there is an inconsistency on the Resistor numbering. The BOM has R1 and R2 reversed in the table. You can see the silk screened names are different in the pictures on the instructional page and on the boards. I am going to follow the markings on the board 10K = R1 and 220 = R2.

8:47: Alright here goes, crappy radioshack soldering iron is hot, lets see how it goes.

9:19: Success, after a few minutes of trying to use the iron at 20W I turned it up to 40W and I was rolling. Soldered a solid 12 joints, at this pace I should be done sometime around winter. Tested it with a power supply and multi-meter and it worked. Got 4.97 V when it was blocked and it seemed to be floating at around .5 to .9V when it was open.


Blocked: (White thing is a slip of paper)

That wasn't too bad. I think I will try to do at least 2 more before I leave for the night.

Wednesday, April 30, 2008

First Parts Arrive

Got my Arduino from "Maker Store" and the PCB boards from RRRF. Parts are supposed to come tomorrow from mouser, lets hope everything is included. Going to take the Arduino home today and see if it will play nice with the new Ubuntu installation on my laptop.