My Current Keyboard Setup

As I’ve written before, I find compact keyboards to be more comfortable than normal full size keyboards.  Compact keyboards are also called Tenkeyless keyboards since they do not have the numeric keypad on the right.

I currently have four compact keyboards:

1. My original, a Lenovo Ultranav scissors switch keyboard with trackpad and trackpoint.
2. An IBM SpaceSaver M4-1 keyboard with trackpoint.  It was made by Lexmark and has rubber dome key switches.
3. Two Unicomp Model M Mighty Mouse keyboards and two Unicomp keypads.  These keyboards have rubber dome key switches.

The IBM and Unicomp keyboards are quite similar; for example, I can use the Unicomp keypad with the SpaceSaver keyboard.

My current work setup (shown above) is a Unicomp keyboard and keypad with my Kensington Orbit trackball in the middle.    I like having the keypad for heavy number entry; I like the keypad being out of the way since I don’t use it often.

The SpaceSave and Model M keyboards have a different feel than the UltraNav; they’re more crisp and clicky.  I like both styles (especially the Lenovo keyboard on my laptop), and both are much better than the typical, mushy keyboard.

Sometime I do want to try a mechanical keyboard, probably something with Cherry MX Blue keys such as a Leopard.  I find illuminated keyboards interesting; I’m pretty sure I’d want a tenkeyless one with Cherry MX Blues (unlike the Deck 82 which only comes with Cherry MX Blacks)

Although Unicomp doesn’t make a tenkeyless buckling spring keyboard, I’d still like to try a buckling spring keyboard (probably the EnduraPro).

The best resource on great keyboards is, of course, geekhack.org; for example, check out their mechanical keyboard guide.

A CANOpen profile is a standard set of objects to interface to a particular device type, such as inputs, outputs, encoders, or motor drives.  A profile that is still being evaluated is called a Draft Standard; eventually it will become a CiA (CAN-in-Automation) standard.  So CiA 402 was originally called DS402, and is still often called DS 402.

Most CiA standards are available from the CAN in Automation web site for free by requesting the desired standards.  However, CiA 402 is not available.  I suspect the reason is that CiA 402 is now part of the IEC 61800-7-201 and IEC 61800-7-301 standards, and thus are only available from the IEC.

I was able to locate and download a copy of the older DS402 standard; there might be a few changes, but it should be good enough for my uses, and I also have the various manufacturers’ guides on how they implemented CiA 402.

Ease of use is one weakness of CANOpen.  I’ve been looking through DS 402 and although it may be well designed, it’s not easy to learn.  I think more vendors should do what Copley Controls does: provide a much easier to use interface that makes it much faster to get started with their drives.

Another approach is to have a motion controller that controls the CANOpen axes, such as the Schneider LMC (Lexium Motion Controller) series, the Elmo Maestro, and (for Ethernet PowerLink) the Balder NextMove E100.  In this case, your program interacts directly with the motion controller instead of the CANOpen drives.

Here is what I found:

• Tri-PLC’s i-TRiLOGI free development environment supports both ladder logic and their version of BASIC and includes a simulator.  Tri-PLC also sells low cost PLCs.
• Infoteam’s OpenPCS free development environment supports all the IEC61131 languages (including ladder and structured text) and includes a free PC-based simulator.  Infoteam’s business model is similar to CoDeSys:  customizing and charging money for the OpenPCS runtime.  (CoDeSys also has a simulator, but their free download is time-limited to a maximum 1 hour continuous run time.)
• EasyPLC is basically a soft-PLC with a HMI builder and is free in demo mode (simulation only).  It’s worth a look: for example, its simulation mode includes 3D.  The commercial license is affordable, starting at 50 Euros).
• I vaguely recall rumors of being able to use an Allen-Bradley simulator for free, but couldn’t find anything when I searched (besides,  I don’t think the development software would be free….)

I choose to download and try out OpenPCS because I really like having support for all the IEC61131 programming languages.  I haven’t used OpenPCS enough to be able to discuss it intelligently, but hopefully I’ll be able to write more in a month or two.

If you really want to learn PLCs, then at some point I think you have to buy a real PLC and connect it to real sensors and outputs.  Simulating stuff just isn’t the same.  Real PLC’s can be quite affordable; many manufacturers (including IDEC and Siemens) sell complete kits (PLC and software, plus sometimes a HMI) for $250-$400, Tri-PLC and the Automation Direct Click! series are <$150 and have free software, Panasonic FPWinPro 6 Basic is free (but code size limited), etc.

Beyond PLC’s there are some interesting options.  For example in the PAC world Opto 22 has a free IDE and control simulator, but you need Opto 22 I/O since there’s no I/O simulation.  In the robotic world, Denso Robotics has a free 3 month trial of WinCaps III which includes 3D robot simulation with no controller required.

Back in the PLC world, I’ve finished reading Cascading Logic; it’s a good book, and I hope to get a review up fairly soon.

All three keyboards are pretty similar.  They use a collapsing rubber dome to press together contacts laid out on two sheets of plastic separated by a plastic spacer.

I’m not going to give detailed steps, since other keyboards are probably a bit different, but here are my notes:

• I used Aqua’s Key Test which I found via Geekhack.org to test each key so I knew where to look for problems.  It’s very hard to test all the keys using a normal program like Notepad.
• I highly recommend taking plenty of pictures at each stage.  OK, I didn’t, but I had two other keyboards I could look at when putting everything  back together.
• I used CaiKote 44 to repair broken traces and re-coat unreliable contacts.  I paid ~$6 for the 1.0g jar at Fry’s.  It worked well, although it’s hard to apply precisely, especially using the included applicators, and worked best with a long time to dry (I let it dry for a day before re-testing the keyboard).  The jar looks small, but it does last: I was able to fix up all my keyboards, and a friend fixed a musical keyboard, without running out.
• I took all key caps off.  I think there’s a chance you could get the keyboard apart with the keys still on, but in any case, I needed to see how I could take everything apart and I wanted to clean the keyboar

Was it worth it?  Yes, because I like the size and feel of these keyboards, and you can’t buy either model today.

If you’re not familiar with stepper motors and their terminology (such as unipolar or bipolar), Wikipedia’s article is a good start.  A 4 wire stepper can be used in bipolar mode only, a 5 wire stepper can be used in unipolar mode only, but 6 and 8 wire steppers can be used in either bipolar or unipolar mode.

The exact procedure to use will vary depending on the motor (and its number of leads) and the equipment you have.  Since I have an 2 channel oscilloscope, I decided to use it and look at the phase differences between the leads of my Step-Syn 103-771-16.

My Step-Syn is a 5-wire stepper motor so it has one common wire connecting the center-taps of both coils, and four wires connected to the ends of the two coils.   The wire colors are black, red, blue, yellow, and orange.

The first step is to find the common wire:  the resistance between the common wire and any other wire will be half of the resistance between any other two wires.  The resistance  between the black wire and the other wires was 130 Ohms; between all the other wires, 260 Ohms.  So the black wire is the common.

The next step is to set up the oscilloscope with the black (common) wire connected to the oscilloscope probes’ ground and the two channels connected to any two wires.  You then spin the motor and adjust the oscilloscope settings (V/Div, timebase, triggering, etc) until you can capture a good set of data.  If the waveforms are 180 degrees out of phase, the wires are from the same coil.  If they are 90 degrees out of phase, the wires are from different coils.

If your oscilloscope can be used in XY mode (often used for showing Lissajous patterns), it’s even more obvious: wires from the same phase create a diagonal line while wires from different phases create a circular pattern.  My Fluke 196 doesn’t have a real XY mode, but I used a Tek TDS210 to get the pictures below.

If the wires are connected to the same coil, then the other two wires are the other coil.  If the wires are connected to different coils, then swap out one wire until you find two wires on the same coil.

Suppose I connect the Step-Syn’s orange and yellow wires to the scope.  The scope trace would show they are connected to the same coil; therefore, the other two wires (red and blue) are the other coil.  Or, suppose I connect the orange and blue wires to the scope; the trace would show they are connected to different coils, so I would swap out one wire (for example blue for yellow) and try again until I find two wires connected to the same coil.

The procedure would be similar for a 6-wire stepper motor, except you have to find two common wires, but the procedure would be considerably more complex for an 8-wire stepper.

The final part is determining the how to connect the wires to the driver.  Basically, connect the coil wires up using your best guess.  If you swap wires within a coil or swap the coils you will change the direction of rotation.  I’ll give a real world example in a paragraph or two.

When I got ready to connect my Step-Syn motor to my Stepnet I discovered I had a problem: the motor is unipolar only while the Stepnet is bipolar only.  The Stepnet manual doesn’t state that (there is no mention of bipolar or unipolar stepper motors), but it became obvious when I looked at the motor connection diagrams in the manual.

Sometimes you can convert a 5-wire motor to a 6-wire by taking the motor apart, cutting the connection between the two center-taps, and then bringing out the second center tap.  I did take the case off the Step-Syn, but I didn’t see any obvious way to bring out the sixth wire.

Since I still wanted to test this motor, I decided connect it to a Allegro Microsystems UCN5804 unipolar stepper driver.  I connected the black wire, Pin 2, and Pin 7 to +24VDC, orange to Pin 1, yellow to Pin 3, blue to Pin 6,  red to Pin 8, and Pin 14 (Direction) is tied to ground.  The motor rotated the direction I wanted: clockwise when viewed from the front.  Using the UCN5804 datasheet, I determined that in 2-phase drive the wires were energized in the order yellow/red, red/orange, orange/blue, and blue/yellow.  In wave mode (1 phase), the wires were energized in the order red, orange, blue, and yellow.

Swap two wires within a coil, for example, yellow and orange.  yellow is now connected to Pin 1 and orange is connected to Pin 3.  The motor now moves counter-clockwise.

I normally start by googling around.  In my experience Google returns better results than Bing for technical searches.  I typically start with the manufacturer (Sanyo Denki) or type (“Step-Syn”) and part number, and modify my search approach depending on the results.

If the manufacturer has a good datasheet on their website, googling will typically find it faster than going to their website.  Unfortunately, many manufacturers do not provide datasheets for their older, not in production, products.

I recommend reading up on advanced search techniques.  Here are some I use frequently with Google:

1. Add filetype:pdf to search only PDFs (since datasheets are often PDFs)
2. Add site:url to search only within the given URL.  For example, adding site:sanyo-denki.com returns results only from within the sanyo-denki.com domain.
3. Use quotation marks to search for a complete phrase.  Searching for Sanyo Denki will return results that have both words in the page (but not necessarily together), but searching for “Sanyo Denki” will only return pages that has the phrase Sanyo Denki.
4. Use a dash to eliminate search results; for example, adding -eBay will skip results with the word eBay in them.  -eBay is very handy if a whole bunch eBay sellers are cluttering up your results.
5. There are many more, so try searching for posts about how to search…

I also look at the manufacturer’s web site; occasionally the web site’s search box returns results Google can’t find.  Sometimes you can find data based on the product line, not the specific part number (which may not appear because there are so many variations; the datasheet just lists the possible options).  For example, I received the best results for the Oriental Motor Vexta PH265L-04 by searching their catalog for PH265*.

Let’s look at some searches for the Sanyo Denki 103-771-16:

1. Searching for Sanyo Denki 103-771-16 currently brings up 8 results, none of which look useful (and 3 refer back to here!).
2. Searching for Sanyo Denki 103-771 brings up a lot more results, but I didn’t find any useful data.
3. Now let’s get creative and add the wire colors: Sanyo Denki 103-771 blue red black orange yellow returns interesting looking results.  Unfortunately all of the Sanyo Denki PDFs are for newer motors that are wired differently.

So sometimes even Google can’t find what you want; instead, in the next post, I’ll look at how I determined the Sanyo Denki stepper’s connections.

The box

Front View

Side View

Back View

I recently bought an ITW ActiveMetal button because the price was somewhat reasonable, because it uses a unique technology, and because they are no longer readily available after ITW sold the technology to Texzec.

The only distributor with any stock left is Newark; when I ordered mine, they had a total of 5 units available in 3 models.  I bought a T01-042203-006-NO-M2 which breaks down as follows:

• ActiveMetal button using ultrasonic energy trapped in resonant cavities.
• Zinc alloy housing.
• 22mm size
• 10-24 VDC input, Open collector output.  Since I’m using it with a PLC, I like 24VDC, and the open collector outputs let me use the button with sourcing or sinking inputs.
• Bright chrome color (I also considered the mirror black color)
• Normally open switch status
• Momentary switch action
• Medium sensitivity level.

The price ($37) is OK for a metal button.  The chrome looks very sharp, but might scratch easily (mine already has a scratch); I would probably pay extra for stainless steel if I were going to use them on a machine.

I won’t make any promises,  but it appears to be ESD-safe; all the exposed metal is grounded together with the black ground wire, although there is noticeable resistance when measuring between various places on the metal surface and the ground wire.

I have the button connected to a Panasonic FP Sigma PLC with PLC inputs configured as sinking (the load provides 24VDC), since I am currently using the PLC with a few PNP-output Pepperl Fuchs inductive sensors.   I have the connected the  button’s red wire to +24VDC, the black wire to ground, and the green wire and a 4.7K Ohm pull-up resistor to the PLC input.

The button does take a little pressure to actuate, so anything that presses hard enough on the button should actuate it (I tried various objects with no problems).  However, because there’s no mechanical feedback, you can’t tell if you’ve successfully pressed it.  I would always use the button with some kind of feedback; currently, I’m using the PLC’s input status LED.

If you need to press a button frequently, the ActiveMetal’s light touch could be an advantage compared to a typical 22mm mechanical pushbutton.  Recently, I was testing out an Allegro UCN5804 stepper driver using my ActiveMetal button to generate the step pulses, and I appreciated its ease of actuation.

In most cases I think I’d rather use a nice illuminated mechanical pushbutton (such as the IDEC LW7L), but if I need the unique advantages of a non-mechanical button (such as better ESD safety, longer life, or greater robustness), I’ll definitely consider ActiveMetal buttons.

Hall Effect Pushbuttons

Hall effect pushbuttons are cool because they have a stroke, like a mechanical pushbutton, but can last for millions of cycles.

• ITW Switches has a wide variety of hall effect pushbuttons, including metal and illuminated large panel mount switches, such as the Series 48SS, the 48M-SS, 57M-SS, and 58M-SS.  However, availability is poor; for example at Mouser I only found a few 48SS models (but they were all less than $20).
• C&K has the HP series.
• APEM has the IH Hall Effect Switches.  The IHS models are panel mount switches start at ~$40.  The IHL models are unique: they have a linear 0.5->4.5V analog output over the switch’s 4mm travel, and cost ~$60.  However, I think a T-Bar or one axis joystick would be a lot easier to use, although they would typically be larger and more expensive.

Finally, I have to mention Schurter’s MSM CS series: they are mechanical vandal-resistant switches with a ceramic actuator.  The ceramic material makes for a very cool looking button; see the PDF datasheet for pictures.  Prices start ~$25.

1. Easier to use in ESD-safe applications (since there is only one part to ground, and many models are made of conductive metal).
2. Great durability, up to 50 million cycles or more, since there is no mechanical wear.
3. Better washdown and cleaning for medical and similar applications, because they have fewer cracks to hide nasty stuff.
4. Better resistance against vandals (since the exposed part is made from one piece of metal).

Potential disadvantages include:

1. No tactile feedback; great feedback is one of the best features of a good pushbutton.
2. Very limited current switching ability; many mechanical switches can easily handle 10A currents.
3. Potential problems with gloved fingers not actuating the button, or with water or nearby objects actuating the button.  I suspect in most cases you won’t have these problems, but you should verify first, starting with the datasheet.
4. High prices, typically $20-$100 (although a comparably sized mechanical button is typically $15-$30).

I found buttons from Schurter (Switzerland), APEM (France), Grayhill (USA), Texzec (USA), C&K (USA), EAO (Germany) and Barantec (Israel); there may be others, too.  I think it’s interesting that almost all of these companies are either European or American.

There appears to be a limited market for this switch type; several companies have dropped lines soon after introducing them, and ITW Switches sold its ActiveMetal line to Texzec.  I’ll mention some of the “missing in action” lines below.

So here are some of the more interesting switches I found, sorted by sensing type:

Piezo Electric Buttons

• Schurter has the PSE line of piezo switches, available in 16 mm, 19 mm, 22 mm, 24 mm, 27 mm and 30 mm sizes.  Cases are made of plastic, anodized aluminum, or stainless steel.  Illumination options are none, spot (1 LED), and ring.  Prices range from ~$20 (CSE 16 plastic), ~$25 (CSE 16 aluminum), ~$45 (CSE 16 stainless) and up.
• Grayhill has the 37F series of piezo buttons.  Cases are aluminum, and prices start ~$20.
• APEM has the PBA series, available in 16mm, 19mm, and 22mm bushing sizes, with and without illumination, and with anodized aluminum or stainless steel cases.  Pricing starts >$30.
• Barantec has a wide range of piezo buttons in 16 mm, 18 mm, 19 mm, 22 mm, and 27 mm sizes encased in aluminum or stainless steel.  Illumination options are none, point, and ring.  Barantec only sells direct in the US.
• C&K had the KP series of piezo buttons back when they were part of ITT Canon, but they are no longer available.

Capacitive Buttons

• Capacitive buttons use a sensing technique similar to capacitive touchscreens.  They can have problems with gloved fingers; however, Atmel claims that many gloves (including typical household, medical, and clean room types) should work fine.  The buttons can often work through a thin non-conductive layer such as glass.
• Schurter had several lines of capacitive switches, including the CSE16, CSE 15 uG and CSE 25 uG.  The CSE 16 models were round metal switches, while the uG models were designed to be used under glass.  Mouser still has a few CSE16 switches left at >$90.
• EAO had the Series 75 capacitive touch buttons, but they are no longer available.
• APEM has just introduced the CP line of capacitive buttons; as far as I can tell, they are not yet available.  The CP line will be available in 16 mm, 19 mm, and 22 mm sizes with anodized aluminum cases.

Ultrasonic Buttons

• Texzec‘s ActiveMetal buttons use ultrasonic energy trapped in resonant cavities.   Available materials are stainless steel, aluminum, plastic, and zinc alloy.  Sizes include 19mm, 22mm, and 30mm.  As far as I can tell, Texzec has no distributors; however, Newark is selling the last of the ITW ActiveMetal buttons for ~$35 (22mm, zinc alloy).

Optical Buttons

I haven’t seen any metal ones, but there are some plastic models, such as these  from Banner Engineering.