Friday, November 18, 2011

Placing Random QRcode on walls!

HEY! Thanks for scanning one of my secret QRcodes strategically placed around UT campus. You are now one of the elite few that will be counted in this social experiment. Years have been added to your life. I swear.

If your interested in electronics and CNC related projects feel free to check out the rest of my blog!

Hope you enjoyed the link! If you're interested in making your own QRcode you can visit some one else's website.

Oh, and feel free to comment on where you found the QRcode placed. I gave several to friends and told them to spread the love.


Sunday, November 13, 2011

Mechanical Portion....CHECK

The CNC has a method of travel now! I finished up adding the power-train components I picked up a couple of days back. I'm pretty excited about that. The X and Y axis are pretty smooth. The Z axis is slightly rough to turn but this may be to the weight of the carriages and router plate. I'm afraid that the motors that I have wont be able to work that axis. We'll see when we get there. For now, we celebrate the victory at hand.
Now I'm going to make you quit being lazy and read from the other side of the screen.

A small list of items that will need to be acquired is growing as we move forward in the project. First is a table surface. A simple half sheet of MDF should do the trick there. Next is a router mount. I haven't decided on what I'm going to use for a cutter but its going to start out small. I have available to me something about twice as large as a Dremel but half as big as a typical router.  Its my dad's. This will most likely be the starting implement due to it's weight.

The next chapter of the project begins today. The electronics section of the project will be executed mostly in my lab (AKA a small room of my house I clutter up with my junk) . I've dug out the hardware that I was preparing for the previous iterations of the CNC. It was like digging for fossils. I had to blow the saw dust and metal shavings off of it with compressed air. As I've mentioned previously the brains of the setup is a Boarduino with an Atmega328. That's now running the latest version of GRBL. Version 0.6. Fortunately flashing GRBL to the Arduino was much easier this time. Used to be you had to compile it from scratch and then run a string of commands to get it to flash onto the processor. Now you just load a hex file using the Hex Uploader found here. It seems that if I was booted into UBUNTU at the time I was doing this that it might still be as hard as it used to with the AVRDude commands and what not. If your forced to do that and get hung up I have instructions on my old blog at  Things may have changed a bit over the past couple of years but the idea should be the same.

Where am I now? So far I have repaired one of the broken Reprap drivers that ended up with a damaged connector early in the process during my last attempt at a CNC. I built four because I fully expected one to not work since it was the first time I had ever ventured into the world of surface mount soldering. It turns out not to be as hard as people make it out to be. All four turned out great and working. Back on topic. I have a working boarduino loaded with the latest version of GRBL, four working v2.3 RepRap stepper drivers, and a modified computer power supply unit to run it all. Things I need. I need to run back and grab one of my stepper motors to test each of the driver boards and get the wiring to a more permanent stage. Then I need to mount it all up, find a test Gcode file,  and hope that the motors are beefy enough to do the job. So that's the plan. Ive got 47 days to finish this up and at this point I am on schedule to meet the goal! Tomorrow its back to the daily grind of school and end of the semester Senior projects. 

Wednesday, November 9, 2011

A home of its own.

Well, I finally got the spare cash flow to order the rest of the power train components for the CNC. I picked up the couplers, shafts, and collars from Ahren at CNCrouterParts. That dude is fast. I emailed him a question and within the hour he had replied. I ordered the gear from him and it was at my house 2 days later. He is legit and a great person to do business with. I also got some astounding service from McMaster. I ordered the ACME rods from them and they were on my door step the next day. Crazy stuff compared to some of the other troubles I've had in the past from other companies.

I went over to my Dads shop to get to work on the power train and ended up building a rolling cart from random scrap pieces of building materials he had laying around the shop! As you can see I've found out you can post pictures beside text. So enjoy this new feature! Any way. There it is. Its held together with what I would call sewing needles (air-gun "nails") and glue. ;-) Its on wheels so its easily movable and once I cut some slots out in the faces of the cart it will be able to hold the electronics pretty well. Unfortunately, building this also means that I didn't even touch the CNC other than to pick it up and put it on the cart.  With classes coming to an end I'm going to have to hit it hard to make some free time to finish this up.  As I sit here and type this post Ive got 52 days 10 hours 40 minutes and 5 seconds...4 seconds...3 seconds... Its coming up on the CNC deadline.

That brings me to my next point. What is finished? Where is the line? I'd like to define that. The end goal is to have a working CNC machine....and something cut from said machine. I want to start the 2012 with a working tool that can be used to take a drawing and translate it into a physical piece you can hold in your hand. With the current hardware I think I'm going to be limited to circuit boards and 2 dimensional objects  due to some of the limitations of my driver setup and the gcode interpreter. We'll have to start there.

What's my hardware setup? Fair question. I think I may have alluded to it in the past. Its another DIY project I did in the past. Its troublesome...its unreliable, Its even ugly but I built it. Its a trio of reprap driver boards that I learned to make using solder paste, surface mount components, and an electric skillet. Yeah it worked great. Really. Anyway the thing is that there's a bunch of wires coming and going from each of the drivers to a boarduino (also a DIY project. First thing I ever soldered). It needs to be cleaned up and wire managed. Currently its all mounted in an old PC case. It ran one of the previous CNC machines I attempted. When I say "ran" I mean that very...very...very loosely. I was able to feed the boarduino a single gcode command through a terminal and it would execute it. Above that things would go wrong instantly. There were timing issues, wiring issues, and above all the screws were just that. They were threaded rods from lowes. The would bind and get all kinds of messed up. Ill try to pull a picture of the one thing I cut with it. Its just a couple of lines in a piece of MDF. I use it as the picture for my Dad when he calls my phone. He takes time out of his life to help me with these projects so I figure he deserves that.

Moving on past that learning experience. This time I have real ACME rods and legit hardware. Things such as helical couplers and thrust bearings.  Things that I couldn't afford back in the first two iterations of this project. Ill end the post with this.

Precision isn't cheap and no amount of engineering and creativity can be substituted for a well designed part. Sometimes you have to bite the bullet and buy the $20 dollar couplers or the $30 dollar carriages rather than trying to engineer your own.