CNC Ox Build Update

Just a brief status update to cover the past few weeks. To be honest, not much progress has been made as I’ve had a surprising bump in my consulting business. (No complaints there — having good IT and Software projects lined up as an independent coder based in Hawaii is always an interesting challenge).

Overcoming TinyG v6 Shortcomings
On the Synthetos TinyG v6 – I’m really starting to hate this controller again. If I were superstitious, I’d say the thing is cursed. Aside from blowing a driver chip, I’m now experiencing problems with the Home and Limit Switches. The underlying problem here is that the TinyG’s inputs are 3.3 Volts, which is quite retarded (IMNSHO). Instead of making things easier on the builder and using 5 or 12 volts for these lines — which would make it a cinch to passively run Normally-Closed switches over a few meters of length without fear of the voltage drop — the wretched thing drives and accepts 3.3 Volts, with specific warnings of destroying the Atmel CPU if you send more than 3.3V on those lines. Ugh!

The way I see it, the only reliable way to work with the TinyG’s 3.3V home/limit switch arrangement is to add extra circuitry to manage the switches on 5 or 12 volts (which I have ready access to from the power supply), and convert that to a 3.3V signal for the TinyG’s benefit.

Selecting and Purchasing Router/Spindle and Accessories
‘Finally ordered a REAL router head for the Ox. I settled on the Hitachi M12VC for two reasons:

  1. There are a handful of reviews about the Hitachi being quieter than most of the other popular routers; and
  2. PreciseBits.com has a variety of collet sizes available for this particular router (well, some Bosch Routers use the same kit). I went with their combo kit  for the most flexibility for this setup.

Aside from ordering a mounting bracket for the Hitachi and a starter set of bits, I’m calling this upgrade done. Next upgrade is to extend the table length (Y-Axis) to the full 3000mm I’m looking for, so I can cut parts from entire plywood sheets. At this rate, I expect to be able to do that in mid-October. Right now, I can work on half-sheets of plywood (4′ x 4′) with the Dremel Clone — when the home/limit switches aren’t glitching up on me. :-p


Repairing the TinyG v6

As luck would have it, once I had my 1500×1500 CNC router fully assembled and tested properly, Hurricane Iselle comes into the islands and sets my progress back by a few weeks. Not only did I need to disassemble the frame and put both the frame and gantry into a safe place during the storm, and then reassemble the whole works a week later, but darn it, one of the TinyG controller board’s chips decided to crap out, too! That’s a bummer, especially since those driver chips are soldered directly to the main board.

The TinyG v6 is no cheap Chinese knock-off 3D printer board with expendable daughter boards, this is an all-in-one unit requiring surface-mount repair tools to get the job done.

I should’ve looked into the next-generation driver chips that the TinyG v7 and later use, and see if those chips are pin-compatible with the chips used in these earlier models. Chances are good I’ll be keeping this machine around for a long time, so it may have been a good time to just upgrade all of the driver chips while I had my soldering equipment out. Oh well. Below are photos of the actual repair, done using a hot air workstation set at 280 Celsius, on a fairly low airflow setting.

Now that this distraction is complete, and my frame is reassembled once more, it’s time to remount the little Dremel Clone onto this CNC and start working on some of the smaller pieces I need to have made. In another month or so, I’ll double the length of the frame (to make the machine a 1500x3000mm beast), and I’ll be adding a beefier router at that time to cut entire sheets of plywood. Finally.

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Portable USB DVD RW

Overall Impression:  These devices are sorely UNDER-rated.

After a few days of testing, I’ve found that these devices perform remarkably well — provided your PC is recent enough to have sufficiently powered USB ports — in particular, USB3 ports. For the geeky-curious, the actual drive inside the USB enclosure that I received reads out under Linux as “MATSHITA BD-CMB UJ-120“.

If your experience finds that these units won’t read discs, or they seem slow at reading discs, I can almost guarantee your USB ports aren’t providing enough power, period. The power required to read Blu-Ray discs, for example, is a lot higher than what’s needed to read DVDs, for example.

Other troubleshooting tips and hints:

If you have a watchful eye, look at the amber “drive status” light — if it seems like it dims out while reading, you’ve got a power problem.

To use these on an older PC or notebook, I recommend adding a cheap 5-Volt wall-wart (power supply) for the power needs. 1.5 Amps minimum, but 2 or more is better.

In a pinch, you can also use the power-plug portion of most recent Android tablet devices with a standard USB “A/B” cable, instead of the Micro- or Mini- USB cable your tablet would use.


OpenBuilds Solid V Xtreme Wheel

Check out these new Solid V Wheels that OpenBuilds is now producing! Woo-Hoo. They’re made from hard polycarbonate material, which is more resistant to compression than the standard V Wheels.

‘Will be keeping an eye on the reviews of these wheels, and (if all looks good) we look forward to maintaining a supply of these wheels as an upgrade option for more demanding CNC Milling needs.

If you’re a local Hawaii maker (Sorry, my offer is limited to Hawaii makers) and would like to try them out, let me know and I’ll give you a good price on your first set of these wheels in exchange for an honest review of them installed in your machine. :-)


1500×1500 CNC Machine

20140709_221421aSo, I’ve been collecting and assembling parts for a large CNC build I’ve wanted to do for years. My ultimate goal is to be able to cut parts out of entire 4′x8′ sheets of plywood, but for now, a simple 5′x5′ (well, 1500mm x 1500mm) machine will suffice.

Most of the parts put into this build are either components I’ve had laying around collecting dust, or they came out of the Gadget Shop’s OpenBuilds inventory. The only real “third-party” purchase was a set of aluminum plates, which are conveniently available on Ebay. I have to admit, those $150 plates are beautifully done, and I’m confident they’ll stand up to anything I plan to do with this machine.

The Controller is an old TinyG v6 that I once used in a ShapeOko v1 – an entry level CNC machine that has since been modified to operate as a 3D printer. I am running a heavily modified version of the TinyG firmware, and a heavily modified version of Repetier Host to exchange G-Code.

Why Repetier Host? Long story. At the time when I was using the TinyG on the ShapeOko, I noticed it would fail miserably due to all kinds of “seemingly-random” serial port data errors.

In other words, I had a bad case of line noise on that setup, and it was almost impossible to get a “clean” plain-text transmission over that serial connection without reducing the serial port’s speed ridiculously low. Synthetos (TinyG’s makers) seemed content with leaving the TinyG to use this “plain text” method of exchanging G-Code, thus I rolled up my sleeves and looked into options that would implement error-correction.

Since I was leaning toward converting the ShapeOko into a 3D printer anyway, I came across Repetier Host. What cinched the decision for me was the fact that Fedora Linux was adding support for Repetier Host. Looking under the hood, I found the source code to be a reasonably well-written solution — understandable and hackable enough for me to build up what I needed to cobble something together on my own.

As for this build, it’s about 90% complete — I’m waiting on a few more hardware components to arrive so I can button down the frame for good (mostly waiting on the cast 90-degree gussets for the gantry). Free time permitting, I hope to be calibrating the motion and making the first test cuts with a Dremel-like router by the weekend.

Yes, I know that dinky Dremel clone is under-powered. Remember – this is still being built from stuff I have laying around as a proof-of-concept. If I can cut simple parts out of plywood repeatably and accurately, I’m good. :-)

Future plans for this machine are to convert it to a 3000mm x 1500mm frame (doubling and reinforcing the frame along its length); and maybe mount a real spindle on there -vs- an off-the-shelf router. The TinyG is more than capable of doing PWM (Pulse width modulation) to control spindle speed.


OpenBuilds Parts Available Again

Good News, Hawaii Makers!

OpenBuilds parts are available from our suppliers once more! With supply issues finally easing up, the Gadget Shop will soon be configured to allow Back-Orders of OpenBuilds parts not in stock on our shelves in Hawaii. (Lead time is 5 to 10 business days to arrive in Honolulu for most components).

More Build Logs and 3D Printer components to arrive on shelves soon!


The Scorched Earth Method

Hello, World.

Sometimes, you have to let go of the old in order to move ahead with the new. Rather than be encumbered with maintaining a legacy, I have decided to cut bait and give my “Internet Footprint” a fresh start.

Blog and Project Build-Logs – All old blog posts and projects are gone, and not likely to return unless it’s something actively being worked on.

Gadget Shop Status Update - For the most part, the Gadget Shop was set up to help Hawaii-based Makers obtain commonly used components in the quickest and most cost-effective manner. “Local Pick-Up” was the preferred method for the original Shop, and that solution has worked reasonably well for the Makers.

Despite my original intent to supply the Hawaii market, and much to my surprise, the Gadget Shop’s Internet popularity has been growing, and (due to the above “Hawaii-Only” restrictions), Mainland and International shoppers have been unable to place orders. In response to this growth in demand, I am hiring additional help, and am in the process of migrating the Shop over to a much more capable (and hopefully easier to maintain) eCommerce platform.

-Laurence Lee


HOWTO: Run TinyG under Minicom

I believe I finally have the Synthetos TinyG v6 working reliably under minicom. To upload Gcode files to TinyG, I found it best to disable the Local Echo ($ee=0), disable the Status Verbosity ($sv=0), disable the Text Verbosity ($tv=0), and finally set the baudrate to 38400 ($baud=3).

The goal of disabling these three options is to minimize “cruft” that is pushed into the TinyG’s output buffers. I suspect (but have not confirmed in the firmware code yet) the TinyG will APPEND the XOFF control code to its output buffer, instead of PREPENDING it in front of anything else waiting in the output buffer.

In addition to the above changes, it appears that uploading text files at 115200 bps is WAY too fast for the TinyG to handle. My guess is that the TinyG winds up sending the XOFF way too late to prevent Minicom from transmitting too much, and at such point, the TinyG’s buffers are already overflowed and your job is hosed.

Experimenting with the lower baud rates, uploading ASCII files from Minicom at 38400 bps is still sufficiently fast enough to fill the TinyG’s buffers (you can tell because Minicom correctly pauses and resumes the file upload when XON/XOFF are received on an ASCII upload). Since the buffers are still filling up perfectly fine under 38400 bps, I have no problem with any perceived “loss” by transmitting at a lower speed.

With those issues out of the way, I can finally press ahead with the ShapeOko project, using Minicom (or anything else) using a Raspberry Pi as the host.


HOWTO: Manually Activate LVM Volumes in Linux

  • By: Laurence A. Lee
  • Published: February 7, 2008

Blecch, I keep getting nailed by this whenever I juggle around my external or removable hard-drives that have Fedora Linux loaded on them.  These are the “magic three” that convince Linux to recognize LVM-allocated partitions on removable disks.  Perform these commands as root:

	lvm vgscan
	lvm vgchange -ay
	lvm lvscan

Thanks to the LVM2 FAQ for providing a comprehensive document, but I really only need these commands to be on my way.

Obviously, this entry is posted for my own convenience and reference, but I’m sure there are others out there who could use the quick answer.

The first two lines should be enough to activate the partitions, but I added the third so you can see what’s actually there.These LVM-allocated partitions should be available as devices under /dev/mapper.