Been pretty lax about updating this blog recently. I have undertaken a fairly time consuming build of a virtual pinball machine. I have been making posts in a forum on that topic as I have required input from that community throughout the build. I am almost(ish) done and will make a video highlighting the process when complete. In the interim, if you want to see some of the gory details you can check out my build log.
Update : Build complete!
My son plays baseball, and keeping equipment organized is an ongoing challenge. While sticking bats in the chain link fence is a time-honored tradition, I thought I would whip up a bat holder. I can’t take credit for the concept, as one of the municipal parks had a similar solution permanently mounted. Mine is a knock-off using 2″ pvc pipe and some rope.
The machining was very simple, its basically two rectangles per bat. The only trick was to do one series of rectangles, then rotate the pipe 90 degrees before doing the second.
My wife started a new project at work, and as this project is a big one, it meant a new notebook! She got a very nice green moleskin, but the cover was quite plain. As we both love the Big Bang Theory I was tasked to put a likeness of Dr. Sheldon Cooper on the cover. Rigged up a sharipe in a pen holder, and off to the races!
Original picture, and gcode here.
I saw this CNC halftones article quite some time ago and setup the the CAM drawing quite some time ago. I never really got around to routing it, as I wanted to test it in two-color plastic instead of the painted plywood the original authors used. As luck would have it, BF plastics had some white/black material on clearance last week so I picked up half a sheet. The material is only 0.1″ thick, so I used 3m spray adhesive to mount it to 1/2″ plywood. About 30 minutes or so with a 60 degree v-carve bit and it was done! I need to pick up a 45 degree bit i think, as this one did go a little deep in places, you can actually see some wood on some of the wider letters. Still looks sharp!
The .dxf and gcode can be found here.
On the machine:
This project was one of those long-running ones which took almost 7 months from when I saw the first one out there and wanted to make one, to when I actually got started. One of the big catalysts was Joe’s blog post on his build – so hats off to him! Joe did perf board wiring, and I wanted to create a circuit board for the task. The reason for this was twofold: (1) I hate perf board and (2) I wanted to build the atmega circuit and bootstrap it myself.
So if you watch the video below, you will see I failed at getting my atmega to run. Could not figure it out! Next time I will surely include additional LED’s (pin 13 anyone?) to aid troubleshooting. So, that said in the zip file attached you will find my eagle schematics. If you use them, be aware the microcontroller portion requires some additional scrutiny. Maybe its fine, and I just messed up the wiring. Who knows. If you want to take a peek at it and give me feedback I would appreciate it!
Other big change/addition from Joe’s build was I added a Real Time Clock (RTC). In my case I used the ChronoDot. It is much more accurate, and tracking time in code was MUCH easier. Here is my code, eagle schematic, and .DXF file for the led array.
I got the components mounted on the main and remote boards. After much deliberation we dropped $12 per remote node to pick up some waterproof plastic ammo boxes to put the electronics in. These boxes will be out in the yard exposed to snow/rain. The boxes worked out very well, as the 3-gang outlet box fit nicely inside. Just drilled a hole in the bottom so the cords can go in/out.
Wiring up the outlets was pretty easy. Common wire was shared across them all, and the hot (black) wire was sourced from the circuit board (triac). I did not use any ground wire as the Christmas light strings don’t have ground. I also used a pretty light gauge wire as I will only be driving a single string of LED lights per outlet.
Got everything wired up at the neighbors and everything worked well. Even with 100′ cat5 runs to some of the remote boxes everything worked well. We did have some flakeyness where it would lock up occasionally after a few hours. I upgraded the wallwart power supply to an old computer supply, and at the same time fixed a solder joint for the ground wire that looked ‘cold’. Not sure which of the two upgrades fixed the issue, but all is good now.
Below is a picture of the main controller board wired up on the workbench. Will post a video of the light show in the next update!
One thing you may notice is the FTDI controller connected via USB. This is due to the fact the Arduino Mega changed the way they emulate usb/serial. This new chip on the arduino is not identified by the software running the lighting show (Vixen). Using an older-style FTDI board remedied that situation…
Its rare that my wife asks me to make something for her. I think its hard for her to get over some internal negative connotation she has with ‘homemade’. This year for Christmas she did ask me to make her a sign for the front yard. My marching orders were for it to be as big as possible, and to say ‘Believe’. My CNC machine has only a 2×4′ bed, and for the first run at this I didn’t want to be patching together multiple boards. I chose to use 1/2″ plywood, as painted I think it will hold up pretty well to the elements.
First order of business was to grab an appropriate font. I usually go to 1001freefonts.com. No affiliation, but they have a nice selection of free fonts, and there is no hoops to jump through to get them. I chose the new font, typed up the word, and expanded it to fill my 2’x4′ work area. I then did a profile around the word, leaving a 2″ gap all around. The ‘fanciest’ part of this design was to use vectors to draw inside the letters to outline where the lights would go. My software could then space holes along those lines, and I chose to space them 1″ apart – end the end this worked out very nicely. The only other open question was how big the holes should be. Using my calipers I found out the lights were of inconsistent size. Most were around 0.21″. In the top center of the drawing you can see where I had a few holes of differing sizes that I machined initially to determine which size hole would have the best ‘friction fit’ to hold the lights in.
I painted the 2×4 sheet bright red and let it dry overnight. From there it was off to the CNC. I had big plans to use a contact paper (for lining drawers) mask for masking off the letters so they could be easily spray-painted white. This did not work well, and I would not do it again in the future. The mask isn’t super sticky, and it had a tendancy to pull up when routing. It also had a tendancy to ‘melt’ when sprayed with the spray paint I had. Regardless, my first machine operation was a profile to cut the mask with a downcut bit. This will also prevent tearout on future machine operations using an upcut bit.
So what you see here is the mask, along with repairs to mask made with blue painters tape.
Second operation was to pocket the letters. This was just a shallow 0.2″ pocket. I then cut out the sign, spray painted the pockets (letters) and removed the mask. The led lights inserted from the rear with a friction fit, no adhesives used. Sorry I didn’t think to take more pictures of that process. Below see both day and nighttime photos of the final product.