Merging modern software development with electrons and metal

Autodesk just released the beta version of the 123D 3D mechanical CAD program.  It’s meant for hobbyists, but Autodesk surprised me by including both STEP file import and export.  (Free or low cost commercial CAD programs almost always don’t include free STEP file export).

123D is the standalone version of Inventor Fusion, so it is a direct modeler (not a history based like SolidWorks or Alibre).  So put together free, easier to use (direct modeling), and STEP file import/export, and it should work great for creating 3D PCB models.  There could be some problems, such as assembly limitations (such as a low maximum number of parts), or the EULA (so far the 123D End User License Agreement appears to be the standard Autodesk one, with no mentions of restrictions on commercial use).

I haven’t been able to check out 123D’s PCB prowess yet because I haven’t been able to get it to start successfully.  I’ll give it another try in a while.

Pretty funny post over at Paul Rako’s Anablog on pranks, starring analog chip designers.

Fluke 196 with Pelican Case

Why do I have an oscilloscope?  The real answer is that scopes are cool, and many years ago, I couldn’t resist when Fry’s had Fluke Scopemeters on sale — at 50% off!  So I own a 100MHz dual trace Fluke 196 Scopemeter.  Later I bought the yellow the Pelican case for it; the two are a great combination.

Since software ties everything together, I’m also the “systems” guy, and thus I should be able to troubleshoot the entire machine.  I do use my multi-meter much more than my scope, but the oscilloscope is essential when troubleshooting encoders, hall sensors, and the occasional electrical glitch which won’t show up on a DMM.

I’ve used other scopes, such as the Tek THS720 handheld, the Tek TDS 210 desktop, Tek analog scopes, and a Heathkit analog scope.  Recently, I participated in a hands-on demo of the new Rhode and Schwartz RTO1014 1GHZ oscilloscope.  It’s quite impressive, even intimidating at first, with all the buttons and things it can do.  Fortunately, such high powered scopes aren’t needed for typical factory troubleshooting; a dual channel, 20-100MHz real time digital does fine most of the time.

There is uncommon feature that’s really handy: isolated channels (each channel’s ground is isolated from the others).  With a typical dual channel scope such as the TDS 210, I can only view one differential encoder signal (channel 1 probe on A+ signal, channel 2 on A- signal, display mode set to combine channels).  But with a dual isolated channels, I can view two differential signals (channel 1 probe on A+, channel 1 ground on A-, channel 2 probe on B+, channel 2 ground on B-).

Hand-held scopes, such as the Fluke 196 and Tek THS 720, typically have isolated channels, along with ruggedness, battery power, small size, and a hefty price tag.  However, a 4 channel desktop scope is often cheaper than a 2 channel isolated channel scope.

I once spent a lot of extra time because I was too enamored with isolated channels.  The system had a servo motor with the differential encoder output split, with one set of signals going to a motion controller and the other set going to a custom board.  The motion controller was counting correctly, but the custom board wasn’t.

I set up my Fluke 196 to look at the differential signals.  The B+/B- signal did look smaller (less voltage swing) than the A+/A- signal, but it had to be OK because the motion controller was picking it up.  So I started swapping out components — and kept getting the same problem.

I figured it out when I looked at each signal (A+, A-, B+, B-) individually; the B- signal was dead (because of a broken wire in the cable from the motor).  The motion controller worked because it was less sensitive, managing to count the smaller transitions.  My lesson learned: check everything, and don’t make unsupported assumptions.

Recently I visited San Francisco’s Japantown, and couldn’t resist picking up even more Japanese pens…so here’s what I bought along with some brief commentary (pens described in order from left to right).

All of these pens were made in Japan, although some of the Sailor 0.38 pens (in colors I didn’t buy) were made in Thailand.

Pens from Kinokuniya (Maido) Stationery

Pens from Kinokuniya Stationery (operated by Maido Stationery)

• Uni-ball Signo DX 0.38 Light Blue gel pen.  I love my burgandy red Signo DX, so I had to pick up another DX.  This one is also very sweet.
• Zebra Surari 0.5 Blue emulsion ink pen.  In the past, I haven’t been impressed with Zebra’s pens, but the Surari’s are sweet; I think I like them better than the Uni Jetstream or Pentel Energel.  The 0.5 color range is restricted, but I do like this shade of blue.
  
• Zebra Surari 0.7 Purple emulsion ink pen.  Zebra has an interesting range of colors for their 0.7 mm Surari’s, so I went for purple.  I like this pen.
• Pilot Petit 1 fountain pen.  I’ve been wanting to try a cheap fountain pen, and after extensive testing at Maido, I decided that the Petit 1 is substantially smoother than the Platinum Preppy.  I like the older style better than the new Petit 1.
• Pilot Petit ink (black and red).
• Pilot Petit 3 brush pen (solid tip).  I bought this because it’s cheap, cute, refillable, and uses the same refills as the Petit 1.
• Mitsubishi (Uni-ball) PFK-206 brush pen (solid tip).  It has a fine tip and broad tip.
  

Pens from Ichiban Kan

Pens from Ichiban Kan

• Kuretake brush pen (bristle tip).  I love this playing with this pen, even though I’m not artistic; it’s a steal at $1.75, and I should’ve bought more.
• Uni-ball PIN 01 pen.  I’m not a big fan of felt tip / marker style pens for writing, but I’m interesting in comparing it to the Sakura Pigma Micron.
• Uni-ball Noble Metal Gold pen.  I wanted to check out the Sakura Gelly Roll competition.

Pens from Daiso Japan

Pens from Daiso Japan

• Sailor 0.38 Light Blue gel pen.  It writes well, color is similar to the Signo DX, automatically retracts when put into shirt pocket, but it’s kind of ugly.  Even though I like retractable pens, I think I’d take the Signo DX over this pen.
• Zebra brush pen (solid tip).

What software do I like on my service laptop?

• All my development software.  I never know when I might need a particular software package.
  • However, licensing can be an issue; nobody wants to pay extra money for a license that sits mostly unused on a laptop.  Some software allows for multiple installations.
  • If the software only allows for one installation, I prefer using a dongle to a software key, because it’s easy to move the dongle around — and way too easy to “lose” the software key (I’ve seen it happen every time with software keys, which why I hate software keys).
  • Software licensing based on the MAC address or such, that can be moved around easily (e.g. return key via internet, then check it out on another computer) is better, but is still a hassle.
  • Of course, the best vendors say: “You can copy the software; just don’t tell us” (said to me by a saleswomen for a large German automation vendor).
• Electrical Schematic viewer
  • I don’t always have a paper schematics with me, so it’s important to be able to view schematics on my laptop.
  • Since our schematics are in DWG files, I use eDrawings as a convenient DWG file viewer.  You can also use a full AutoCAD clone; DoubleCAD XT (Windows only) and DraftSight (Windows, Mac, Linux) are both high quality, free AutoCAD clones.
• Merge software with directory comparisons
  • I’ve found file comparison software to be a life-saver.  Version control is great, but a machine in the field might be in a different state.  I can use the directory comparison to quickly see what files have changed, and then zero in on the changes using file comparison, and then merge between the two versions if needed.  Some software handles three-way merges.
    • I just did this kind of directory comparison recently when upgrading two almost-but-not-quite-identical machines.
  • I’ve been using Araxis Merge for a long time, and have no regrets about spending my money on it.  I’ve used some free options (such as TortoiseMerge with TortoiseSvn), but I feel Araxis works better for some file comparisons.   TortoiseMerge doesn’t do directory comparisons.
• If you use a personal laptop for work, consider using a Virtual Machine (VM) to keep your private and professional lives separate.  With USB pass through features, you should be able to access USB, serial (via USB to serial converters), and networked equipment from within the VM.
• In the future, I might look at taking my version control system with me; since I’m currently running Subversion and Trac in a Virtual Machine, I could do it easily by copying the VM to my laptop.

In one of my first posts, I talked about using the prototype PCB industry for low volume machines.  Overall, I think creating custom PCBs are great, although they aren’t always the best solution.  Four years and a of experience later, it’s time for an update with links to more resources.

Designing PCBs

Simplified software just for creating custom break out boards would be great, but I doubt there is enough of a market for such a program.  So I use Eagle PCB, because of its widespread use (and thus available support).

Affordable PCB design software includes:

• At least 3 open source options, the gEDA suite , Kicad, and FreePCB.  Kicad is probably easier to use than gEDA, but I haven’t used either.  Someday I plan to try out gEDA and Kicad, using the Fedora Electronics Lab Linux distribution installed in a VirtualBox virtual machine.
• Eagle PCB ($49-$1494).  A little overkill for automation PCBs, but works well, and has a lot of support (tutorials, support from CADSoft, SparkFun library, etc).
• PCB programs tied to PCB proto houses, including PCB 123 from Sunstone and PCB Artist from Advanced Circuits.  These programs limit your flexibility (check the links for details), but should be simpler (for example, there shouldn’t be any Gerbers to create and possibly screw up), and are definitely worth considering.
• Various other commercial PCB programs, including Target 3001! (59-2999 Euros), Power Station 32 ($50-$2995), Easy-PC ($477 and up), Edwin XP ($700 and up), Vutrax, Proteus PCB ($249 and up), and DipTrace ($75 to $695).

Getting Your PCB Made

There are many good options, but since I do not know enough to rate them all, I will mention a few:

1. I’ve used Sierra Proto Express for many years with excellent results.  Their newer Web PCB service gives even more options, including longer delivery times (with lower prices).  I always order at least 3 boards, since 3 PCBs don’t cost more than 1.  Typically pricing for the No-touch service is around $110 for 3 PCBs.
2. If you just need 1 PCB at the lowest cost, and can wait a while, consider BatchPCB, since they charge by the square inch.  IIRC, pricing is $2.50/sq in for 2 layer, and typically delivery is 3-4 weeks.
3. If you don’t need hand-holding, have multiple designs, and want lower prices, consider Gold Phoenix.  I had excellent results getting 6 different PCB designs made by them at about $140 for 155 sq in.
4. You might prefer a PCB house that will take the files your PCB design software creates directly; that is a little easier than creating Gerbers.
5. Although I don’t use this option, look at the details and consider if PCB houses with free software, such as Sunstone and Advanced Circuits, are a good choice for you.

Component Notes

I’m still using Phoenix for most of my terminal blocks.  For small quantities, Mouser is still typically best, but check your local distributor for larger quantities; ours is significantly less expensive than Mouser or Digikey.

There seems to be a lot better selection of European-style terminal blocks than there was a few years ago, but I haven’t looked at them in detail (I only have so many hours in a day).

I’m looking at using Phoenix UM holders, since I’d like more size options than the UMK series has.

These are low cost programs suitable for designing mechanical assemblies.

Don’t forget you can use multiple programs to overcome the limitations of one program.

Open Source

Both NaroCAD and FreeCAD are under active development, but I’m pretty sure neither one is anywhere close to ready for production use.

They are still worth checking out, because they might have enough functionality for what you need to do.

Free Commercial MCAD

These programs typically have a lot of limitations, the terms can change at any time, but they are still potentially useful.

1. PowerSHAPE-e.  Very powerful, but costs money to export.
2. Autodesk 123D.  Appears to be good match for modeling personal PCBs; has STEP import and export.
3. CoCreate PE, now creo elements/direct PE.  Limited import and export, limited to 60 parts, but good to see PTC has moved it into the Creo world.
4. MEDUSA4 Personal.  Available for Windows and Linux.
5. Autodesk Labs Inventor Fusion Preview.  Time limited preview of the Fusion direct editing MCAD software.

MCAD Under $500

1. Alibre PE ($199).  Very limited import and export options.

MCAD Under $1500

1. IronCAD Draft ($595).  Not a full MCAD program (e.g. can’t create parts), but can create assemblies.
2. Alibre Professional ($699).  Adds import/export options and more.
3. VariCAD ($710).  Available for Windows and Linux.
4. IronCAD INNOVATE XG (~$1300).  Meant for conceptual design, but according to the product comparison it includes “assembly modeling within  a single scene”.
5. Alibre Expert ($1399).  Adds CAM, Motion, MoI, and more.
6. The combination of Rhino ($995 list, available for less) and RhinoWorks ($595, adds parametric and assembly capabilities) might work well.
   

Other Options worth considering

1. ZW3D ($2500 for Standard).  ZW3D 2011 adds direct editing.
2. IRONCAD ($4000 and up).  Innovative MCAD.
3. SpaceClaim ($2450 and up).  Well known for easy direct editing.

Update 4/18/2011: Added Rhino/RhinoWorks

Update 5/22/2011: Added Autodesk 123D, updated Alibre PE price.

My Toolbox series is about my tools for working on machines, including some stories.  I’m going to talk about my tools; your toolbox will be different, but hopefully I’ll give some useful ideas.

Yeah, I’m a software guy, but as the automation software guy, I have the privilege of understanding the whole machine and making sure it is all working right.  That’s why I have a toolbox filled with mechanical tools and electrical test equipment, but I’ll start with service laptops.

Service Laptop

• I’m using Win7 64-bit on my own laptop, but Win7 32-bit is probably the best choice for a field service laptop,  since you should not need >3G RAM, and many device drivers are still not available for 64-bit Windows.
• Since almost all automation software is Windows only, you really have to use Windows.
  • Siemen’s SoftComfort Logo! development environment is a notable exception (it’s written in Java).
  • However, if you can talk to all your equipment via USB (including USB to serial converters) and Ethernet, you could use Linux or Mac OS X as your host OS and run the Windows software in a VM (Virtual Machine) with networking and USB pass through for outside access.  Or you can dual boot.
• I’m partial to Lenovo Thinkpads because of their excellent keyboards and overall quality.  Besides, most Thinkpads support using a FDE (full disk encryption) hard drive, which is a good idea when venturing out with gigabytes of proprietary information.
  • Not all Thinkpads come with with FDE drives, but it’s an affordable do-it-yourself upgrade.
  • Thinkpads are more affordable at the Lenovo Outlet, and you still get a 1 year warranty.  If an older Thinkpad is good enough, and a shorter warranty is OK, then TigerDirect often has great deals (<$400) on off-lease Thinkpads.
• Of course there are plenty of other good possibilities.  My advice is always get a business class laptop; I’ve seen way too many problems with consumer laptops.

Don’t forget the cables

• I typically bring along an extra RJ-45 cable, a standard DB9M/F serial cable, USB extension cable, USB A to micro-B cable, Panasonic FP0 serial cable, and USB to serial port converter (since my laptop doesn’t have a serial port).
• I normally don’t bring along all the special serial stuff, like null modem (laplink) cables, DB9/DB25 cables, and assorted gender changes.  I’ve only needed something weird once in the past 5 years.

Other Computer Hardware

• A 4G or larger USB memory stick.
  • I frequently have to transfer files without using a network.
  • If you work with really old computer systems, a USB floppy drive would be useful.
  • Don’t forget the memory stick!  Always remember to put it back in your bag or pocket.
• 3G/4G wireless is a nice option, so you can access the internet to research problems, download files you forget to do earlier, and such without needing access to the customer’s network.
  • On the other hand, 3G is another monthly fee (typically $40-$80/month in the US) for a service that’s typically not often needed.  If AT&T does complete its acquisition of T-Mobile, expect prices to go up.
  • Pre-paid (from Virgin Mobile and others) gives the option of paying only when needed, but pre-paid is more expensive for heavy data use. Walmart probably has the best pre-paid deal: $20 for 1G for 1 month.
  • Another option is tethering (via USB cable, Bluetooth, or WiFi) to a cell phone with 3G/4G.  However, tethering usually adds another monthly charge (often about $15) on top of the data fee.

Clearance-priced Rhodia Notebooks

I noticed my local Target started carrying Rhodia notebooks a couple months ago.  They were a little pricey for my budget, so I didn’t get any (I’m not  addicted (at least not yet) to pricey notebooks or fountain pens).

Then they disappeared.  Where did they go?  I saw the solution at another Target: they are now on clearance.  I couldn’t resist the clearance prices ($1.31 for the lined notebook, $2.54 for the Reverse square book),  so I bought a bunch.

I’m not sure why the Targets here (Silicon Valley) are dropping Rhodia.  My impression is that my local Target has reduced the size of the paper (notebook, notepad, etc) section by 50% or more, with a corresponding reduction in selection.

Update: I checked another Target, and they have the same clearance deal.  So if you’re interested in these Rhodia notebooks at firesale prices, check your local Target before they’re gone.

I’ve reached this point with my local telephone service; it’s now at ~$28/month for unlimited local calling.  My cell phone bill is just a bit more, but is a much better value.

I could go cell phone only; however, my wife values the local phone number (she is the main user), and we both like having a phone number for people we don’t know, such as banks, schools, etc.  I could also change to metered local calling, but it doesn’t seem worth it to potentially get stuck with overages for a still substantial ~$22/month.

So, I’m moving to dump AT&T.  The big duaolopy (phone & cable) tries to make it hard by charging you a lot more for unbundled services, but it’s still a better deal than paying for unwanted bundling, such as voice & DSL or cable internet & TV.

I have a lot of choices for VoIP (voice over IP), such as Skype, magicJack, Ooma, iTalkBB, and Asterisk-based systems, but I’ve installed a refurbished Ooma Hub from Fry’s.  The cost is affordable (under $4/month for taxes gets me unlimited US calling), it’s simple to install (unlike Asterisk), works with our existing phone (which my wife likes), doesn’t require a computer (unlike magicJack), and it includes E911 services (unlike Skype).  So far it’s working great.

The final step is to switch my internet to non-AT&T/non-cable, for example, Dry Loop DSL.  The savings at first won’t be huge (about $10/month), especially considering I have to invest some money up front for Ooma ($100) and a new modem ($50-$100).  But there’s no chance the phone rates are going down, so the sooner I change, the sooner I’ll start saving.

The same logic applies to business.  Your CAD is asking too much in maintenance fees for too little value?  Seriously investigate changing (or use a mix); there are good alternatives, some of which are probably better than what you are using.  Your PLC vendor nickle and dime-ing you?.   At least start a pilot test using a brand that supports you better.

Changing might be painful, and may not make sense for a variety of reasons, but at least investigate the options, because the chances of these leopards changing their spots are pretty slim.  If you’re going to change eventually, you might as well start sooner than later.