I ran into a snag with my decTOP, which I was planning to use as a radiation monitor: it does not power itself back on after a power failure. This should be changeable in the bios, but it’s inaccessible and emails to Date Evolution have gone unanswered. The power pin is normally 3.3v, and powers up on a rising edge (i.e. you have to release the button before it will start). I described this to Mike Fincham, and he suggested I connect a resistor and capacitor in series, from ground to the power-up pin. The capacitor acts as a switch. When power is first applied to the decTOP, it will begin charging, connecting the power-up pin to ground. When charged, the capacitor stops conducting, allowing the power-up pins voltage to return to 3.3v, and the computer to power up.
It works! The capacitor is obviously a bit large (10 microfarad), but it’s all I had on hand.
The CNC router is now complete, mechanically. It took longer than I expected due to a couple missing/incorrect parts, but I’m pleased with how things are looking. I haven’t started with the wiring yet. I have a computer to run EMC2, but I was using it as a test server for another project, so right now I’m in the middle of transferring everything important off of it. With some luck, I’ll get everything wired up tomorrow.
I just got a player piano on craigslist. The veneer needs some repair and it ought to be refinished, but it plays! I’ve been casually looking for a player piano for the last couple years, but everything I’ve come across has been either too expensive, or in need of significant restoration. This piano is from 1921, but it was restored in the 70’s. It came with over a hundred programs on paper tape, so I spent this afternoon sorting through and playing songs.
I ordered a CNC Router kit from Patrick Hood-Daniel’s BuildYourCNC website. There are a lot of bolts in this kit! The wood is medium-density fibreboard. I suspect it’s plenty sturdy for most of what I’ll be doing, but I still want to mount it to the table.
I’m short a few pieces, but I hope to have those early next week, and have everything working by Friday.
I have a pair of industrial robotic arms that allegedly came off a pcb assembly line. This evening, I tried one out for the first time. It works! I plugged everything in, hit the green run button, and the arm sprang to life (the poor thing thinks its still out on the factory floor). I was able to directly control the motion with the teach tool, but unfortunately, some of the buttons no longer work, so I may try to open it up and repair it. More likely, I’ll just forgo the teach tool altogether, and program it via the serial connection. I haven’t come up with any good projects for it yet, although I do want to try mounting the RepRap extruder on it.
I brought the milling machine up to the house last Saturday. It now resides in the dining room. The controller (not pictured) is faulty, so I’m planning to retrofit it for EMC2. The second picture is of a machine that makes the charts for optical comparators. It was given to me with the mill. I’m not sure what to do with it. It’s a very high quality 2-axis machine, but it’s not rigid.
I have a coal stove in the kitchen and it occurred to me today that there’s no reason I shouldn’t be able to melt aluminum in it. I didn’t have any sort of crucible, so I made one by taking a small piece of iron pipe and screwing a cap onto one end. Then I stuck a piece of scrap aluminum angle into the pipe and sat in in the coal fire:
In just a few minutes, the bottom two thirds of the aluminum angle was molten:
I used a screwdriver to push the aluminum farther down, and it melted in seconds:
I lifted the pipe-crucible out with a pair of channel locks. It was pretty hot:
Unfortunately, I didn’t have anything handy to use for a mold, so I just poured an aluminum puddle onto a fire brick:
The aluminum melted quickly and poured easily. I don’t think I spent more than 30 minutes on the whole project. I’m looking forward to making some molds.
Saturday, February 2, 2008
This is an $8 digital caliper from Harbor Freight. I drilled two holes through the jaws, and the caliper was ready to mount. The scale was a bit too long, so I removed the excess with a hacksaw, and filed it down. That’s it.
I was looking at Fab@Home’s extruder design, and it inspired me to build this cookie dough extruder:
This uses the same motor as the standard reprap extruder and can be controlled by the Reprap Extruder Controller board. It works empty, but I haven’t tried it with dough yet.
