X Stage for my CNC is (one half) COMPLETE!

I'm working on a little CNC machine, most likely for cutting PCBs, but I would like to also be able to use it as a repstrap at some point. It has a stepper motor scavenged from an old printer, some little bipolar job that probably does not have nearly enough torque to drive the machine. I need to get some real motors (Does anyone have a cheap source for NEMA 23 motors?). I have yet to build the control electronics, so the machine has not yet actually run. It is built out of scrap 6061 T6 aluminum angle that I had laying around. It uses both 0.75" and 1" angle. There is also a bit of 2024 T4 0.75"*0.125" bar stock that I used to hold the drive nut. The lead screw is a 7/16-20 threaded rod that uses standard 7/16-20 nuts to drive the actual cart. The guide rods are polished steel 0.25" dowels. The cart rests on the guide rails thanks to 6 drawer wheels that have a convenient 1/4" inner curve that cradles the guide rails perfectly. The cart will actually not fall off of the rails when upside down, even without the lead screw in place. The U-Bolts that hold the two halves of the cart together will also form the basis of the y-tower that will soon ride on top of the x-drive. Enough blather. Some pictures, anyone?

MoodMixzer Part II Troubles

This is the second post about the MoodMixzer. At this point, PWM is working on the small LEDs, and the LED bulb is done. Now that I have attached it, however, problems become apparent. The LED bulb only PWMs correctly when the board is attached to the programmer. I don't understand why this is happening, but it is. I'll attach a schematic of the system. Basically what happens is that the LEDs will PWM correctly for about 1/2 to 3/4 of a cycle (0% - 100% - 0%) and then they will space out, flicker madly, and reset to begin this cycle anew. Any help left as a comment or directed straight to me in irc (#sparkfun on irc.freenode.com) (I'm Stevetronics) Thanks!

MoodMixzer Part I

This is an RGB mood light. All three LEDs have 8-bit PWM from an ATtiny84, my recent workhorse. It uses fast PWM, and the system runs at 20MHz. It runs at 5v from a 7805 and wall-wart. The power LEDs are buffered from the ATtiny's IO pins by3 2N3904 NPN transistors. They buffer the IO pins from the relatively large current pulled by the LEDs. There are 3 small LEDs along the side of the board so that I can debug the code without hooking up the (painfully) bright tri color LED (that I built). I haven't yet put the rgb 'bulb' into the system, I'm using the debugging LEDs. Also, once I have an enclosure (working on it!) I can mount the rotary switch and potentiometer for color tuning. The flickr photostream is here.
(further posts are coming.)

ATtiny84 RGB LED Mixer: Part One

This is a little project that I came up with. I've wanted an excuse to use some fancy knobs for my rotary encoder and this pot that I had, so I built an RGB color mixer with them and an ATtiny84 controlling the PWM side of things. This being my second foray into AVR programming, I had help close by: Eric Agan via #sparkfun on irc.freenode.com. I would have been sunk without his close and patient code checking and debugging. Thanks a ton, Eric! But the basic premise is this: The user uses the rotary switch to select one of the three LEDs and then the potentiometer adjusts the color. There are two unused poles on the rotary switch, so in the future I may add a master brightness feature, preserving the mix, but reducing overall intensity, and a "mute" feature that temporarily dims/shuts down the LEDs. It's programmed in my case with an STK500v2 over USB through WINAVR (I recently switched back from Ubuntu 9.10 to Windows 7) The whole conglomeration runs at 5v for now on the breadboard, but the next version will buffer the high-power real LED through transistors and will run right in its 3.6v power band. The pictures will show two LEDs: One red and one green. The third IO line has a pin in it for my oscope to look at. I am fairly fanatical about clean breadboarding, so the only bit of disorderliness that I will tolerate is in the Pot and switch wiring, simply because it has to be.