It’s been over a year since my last post. (has it really? yikes.) Here are some things I’ve been working on too intensely to allow myself time to write about them:
Pouring a Concrete Machine Tool Base
When the Artisan’s Asylum opened the doors to their new home on Tyler st, I had a good deal of work to do setting up my 6’x8′ renter’s space. One of my first projects was to pour a concrete slab to mount my lathe to, thus lessening vibration and increasing rigidity of the ways. This deserves a post, as I did make a few mistakes along the way
I made a nice lockable birch ply cabinet to store my more expensive woodworking tools at my shop.
Maple and Birch File Cabinet
My first real woodworking project, I made an “heirloom” file cabinet for my sister for Christmas. This more hours to complete than I kept track of.
30 Amp 13.8v Linear Power Supply
I really like how stable and powerful this turned out to be. Originally I built it for ham radio, but found a ton of other uses for it. I also plan to use it for anodizing aluminum one of these days.
20mA to 8.9 Amp Constant Current Load
A constant current load is a VERY handy thing to have around. Besides testing supplies, circuits, and batteries, you can also plug it into any circuit to effect a constant-current supply. (This would be used in conjunction with the supply above for anodizing.)
Wood Router Table (manual) with precision position fence
This mostly-MDF beauty has acme threaded rod, timing pulleys, and a nice dial (engraved using my automated dividing head). With these components I can place the fence to within 0.001″, +/- 0.005″ repeatability. A small insert machined from 1/4″ aluminum plate holds a Bosch 1617EVS 2.25HP router. The Z is set to within 1/64″ using Bosch’s simple but nice depth adjustment on the RA1161 fixed base.
2-axis webcam “turret” for surveillance
I built a platform for a webcam using 2 servo motors. The servos are driven by an arduino which is connected to a linux box running Apache. A user can connect to the web server and control the streaming webcam’s position via a jQuery app.
ABS Plastic Filament Extruder
After making small strides toward a working prototype, this project fell to the wayside. It’s fun working with PID controllers, cartridge heaters, and high torque motors, so I will probably pick up work on this again soon.
Light-duty CNC router
With the exception of linear slide bearings, this machine is completely designed and machined from scratch. It is a moving bed, stationary spindle (bridgeport-style) type mill with an x-y working area of 12″x6″, and a 5″ travel z-axis. The spindle is an ER-16 collet holder with high quality angular contact bearings and runs from 2,000 to 10,000 RPM. It’s belt driven from a 30v brushed DC motor, which is driven by a PID motor controller of my own design. That project in itself was a massive undertaking, so I will give it it’s own topic.
PID Motor Controller
I designed this controller to be arduino compatible. An ATMEGA328 is the brain which processes input from 2 switches and a rotary encoder, and updates an LCD display with motor speed, output percentage, and load. The output is set by a custom PID loop that I coded without ever seeing source for a PID control program. To say I learned a few things with this one would be an understatement. Here are some topics covered in this project:
-AVR ISP programming
-rotary encoders, quadrature encoding, gray code
-configuring all 3 atmega328 timers
-driving capacitive loads
-high-side/low-side mosfet circuits and drivers
-the Miller Plateau
-PID control, tuning, wind-up
-calculating speed, acceleration, and average speed from period (not as simple as it first seems)
-driving a bicolor led with 1 pin
-getting 3 colors out of a bicolor led (still driving with just 1 pin)
As you can see, lots of stuff to write about, so I hope to get this project documented and on it’s own page soon.