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Another Way To Make Your Own Metal Buttons

I have to say someday I’d like to make my own metal buttons.

In the past, I’ve covered Microchip’s mTouch metal-over-cap technology (here and here), which uses capacitive technology.  Microchip has a groovy app note which shows some of the ways you can use it, and has an eval kit available for ~$150 (base mTouch kit plus metal over cap accessory kit).

Now TI has a reference design for creating your own metal buttons using TI’s inductive sensor technology.  TI’s reference designs provide that: a reference design with layout, calculations, and notes.  You can’t buy them pre-made, but you can use them as a good starting point.

I’ve glanced through the manual for this reference design, and it is full of good info – and the design is pretty neat, too.  For example, it includes two different haptic types, ERM/LRM and piezo.  I have the HapTouch Booster Pack which features the same ERM/LRM haptics technology, and I’m not too impressed – it’s similar to the haptic feedback from a current smartphone.  (Note that I think the problem is with the basic ERM/LRM technology, not the controller).

Other approaches to non-moving metal buttons include piezo electric and ultrasonic.


March 19, 2015   No Comments

Notes from the EE Live! 2014 Exhibition

In early April I managed to sneak off work for a day and wander down to the San Jose Convention Center for the EE Live! 2014 Exhibition (formerly known as the Embedded Systems Conference).  The ESC has had its ups and downs, going from the San Jose Convention Center (which I like a lot) to the Moscone in SF (bigger, but not better), back to the SJCC, and next year, down to the Santa Clara Convention Center (which is a pretty nice setup, but not the location for major shows).

I skipped ESC last year, so I was surprised how much the show has shrunk.  On the plus side, there was a lot of exhibition floor training sessions, and all the ones I saw were well attended.  In fact, NXP skipped the product booth and only did training.  Since I do enjoy harassing talking to sales dudes and want to encourage companies to come back, I spent most of my time at the vendor booths.  Here are my show notes, which reflect my interests (which tend towards industrial applications, MCUs, and DSPs):

  • I was surprised at the size of the x86/x64 contingent: Intel, AMD, and a trio of motherboard manufacturers (Asrock, Supermicro, and MSI).  There were also several flash vendors.
    • I have to put in a plug for ASRock, because my desktop PC has an ASRock motherboard, and when it had a minor problem (PS/2 ports quit working), ASRock’s service was quite good.  However, the industrial division is separate (and much smaller), selling compact industrial motherboards direct or through distributors such as Logic Supply.
  • TI had a pretty big booth, showing off their more embedded-oriented lines (no C6x DSPs or analog), including the BeagleBone and the various LaunchPads.
    • TI’s EE Live! 2014 videos are available on Youtube.
    • TI still did their tool swap, so I traded an old Philips 8051 CAN dev kit for a shiny new Tiva Connected LaunchPad, which I have since donated to an eLua volunteer.  TI said the Connected LaunchPad was very popular.
    • I had fun discussing industrial safety (standards, light curtains, safety PLCs, and such) with the Hercules guys – and verified that the RM48 Hercules MCUs do indeed support double precision floating point.
    • It’s always fun to see motors run, and TI was demonstrating their InstaSPIN techology with a conveyor.  I had fun complaining about too many serial encoder protocols (Biss, EnDAT. SSI, Panasonic, Tamagawa, etc).
  • Microchip had a pretty big booth, with a wide array of products.  The new PIC32MZs are pretty impressive, but what I wanted to see was their metal-over-cap button technology.  Microchip has been improving it; this year they showed off metal dome capacitive buttons (my favorite, since they had good tactile feedback) and backlit buttons.
    • Microchip App Note AN1626 [PDF] has lots of interesting information on how to design and backlight metal over cap buttons.
    • The backlit buttons were a demo of Demmel’s metalLight technology.
    • The tactile buttons were a demo of grafos steel’s Click-Inox technology.




  • ST ran a lot of in-booth seminars;  I listened to the mbed presentation for a while (and now want to learn more).  I didn’t spend much time looking at their products since I’m pretty familiar with them.
    • ST was giving out STM32F401 Nucleo boards if you were lucky enough to get a goody bag (I managed to snag the second-to-last bag).  This Nucleo includes the sweet STM32F401 MCU, Arduino headers, and mbed compatibility (SDK (Software Development Kit) and HDK (Hardware Development Kit)).
  • Atmel didn’t have a booth: instead they had their roadshow trailer.  The coolest demo was a 3D printer, powered by Atmel of course.
  • NI had a booth showing off LabView and their hardware, including a motion-and-vision demo featuring Kollmorgen drives and motors.  I spent most of my time there discussing industrial applications with a guy from Xilinx who is interested in industrial applications (such as real time Ethernet) for FPGAs.
  • I took a class from Rhode & Schwarz on oscilloscopes basics, and received a free Digital Stimulus Board for my time.  My big take-away from the class: short, good grounds are critical (long, looping ground wires can be great antennas).  Their oscilloscopes are impressive and fun to play with, but quite a bit more advanced than I need.
  • I stopped by Pico Technology briefly to see what was new.  Pico makes what are probably the highest end USB oscilloscopes.  Some of the newest models support USB 3.0.  Another series has variable resolution (you can trade slower speeds for increased resolution).  Most of them are fairly large.  I asked about USB latency; the salesman said they used some tricks, but noted that they perform a lot of processing in the scope using a FPGA, so the USB connection isn’t as critical.
  • Vision Components was showing off their OEM smart cameras, so I stopped by as always to see what was new.
  • I stopped by Acces I/O and chatted about industrial Ethernet protocols and data acquisition.  Their USB-DA12-8A is one of the more affordable options if you need a precisely timed DAC output.  And they might have some good stuff coming in the Ethernet DAQ arena.
  • I talked briefly with Sealevel Systems; they make a variety of industrial grade computers, serial interfaces, digital I/O, and analog I/O.
  • Trinamic was showing off their stepper and DC motor drive chips, boards, and enclosed drives.  Although they’re not the best fit for my current requirements, they’re worth checking out, and have some low cost models (especially for the chips and boards).  Some models support CANOpen or EtherCAT.
  • Silvertel was showing off a variety of PoE modules, with prototypes up to 200W.  They claim their module pricing is cost-competitive with rolling your own up to medium volumes (say 1000’s or 10,000’s per year).

April 23, 2014   No Comments

Legacy Product Support, eBay,and Sales

Automation component suppliers should provide at least minimum support such as downloadable manuals and drivers for forever.  First, many machines last a long time, and customers need to keep them running, including if manuals or drivers get lost.

Second, it’s smart business to support the second hand market, such as eBay.  I often buy automation equipment from eBay, and I expect reasonable support, which means I can download documentation and drivers; I don’t expect free tech support.  (I understand that for controllers such as PLCs or motion controllers, the programming software often isn’t free; I won’t buy that controller if I can’t program it).

My eBay purchases have lead to some substantial orders.  I still might have selected the Copley Accelnet servo drives, but having myEBay units really helped.  Right now, I’m considering using some AllMotion servo drives for a very specific application; the only reason I am considering AllMotion is because I have one I can use to prototype the system.

Yes, I can (and have) received loaner units, but it’s a hassle, not all companies will provide them, and some times there’s a long time between using something and being able to spec it into a machine.

Microchip is the classic example; they make microcontrollers (MCUs) and owe much of their current success to the fact that they are hobbyist friendly.  Many of the their microcontrollers are still available in easy to use DIP packages, they provided good documentation, support, and free software.  Their chips became very popular with hobbyists, who created an ecosystem of designs, articles, forums, etc, which over time has led to substantial production orders, especially as people familiar with their chips moved into engineering positions.

September 23, 2012   No Comments

Cool Components VIII: Make Your Own Metal Buttons

At the Design West 2012 / Embedded Systems Conference I had the opportunity to try out a unique technology: Microchip Technology’s mTouch metal over cap buttons.  This technology provides the capability to fairly easily create affordable custom non-contact metal buttons.

Since this technology uses capacitive sensing, the buttons are non-contact and should have a long life.  However, they’re still very short stroke and thus provide very little mechanical feedback.  Microchip’s demo used LED point lights to provide feedback.  Microchip’s demo kit currently isn’t available for sale, but they said it was coming sometime, probably for less than $100.

You could use this technology to make ESD-safe buttons.  However, since the metal needs to bend a bit, it won’t be as rugged as the more expensive anti-vandal buttons.

I’ll probably buy the demo kit when it comes out, because it’s a cool gadget…

May 1, 2012   No Comments

Maxtor & Microchip: Somebody Has To Be Different

There’s always one company has has to different.   Back when Maxtor was independent, they spun their disks backwards from everyone else, and numbered their heads from top to bottom, instead of bottom to top like everyone else does.

Microchip is acting the same.  When everyone else, it seems, is using ARM cores for microcontrollers, they picked MIPS cores for the PIC32 micro-controller (MCU) family.  Their new IDE, MPLAB-X is based on NetBeans, instead of Eclipse.

I don’t think the MIPS versus ARM core is a big deal; maybe Microchip got a much better deal from MIPS.  Switching between ARM MCU vendors isn’t easy because all the peripherals are different.  I wouldn’t be surprised if it’s easier to port C code from a PIC24 (16-bit proprietary) to a PIC32 (32-bit MIPS) than from (to take a random example) an Atmel SAM7 to a TI Stellaris MCU simply because the peripherals are much more similar on the PIC MCUs.

On the other hand, I don’t see the advantages of NetBeans over Eclipse.  Both are Java-based IDEs.  Both are open source.  Both are cross-platform.  (Note that an IDE based on either one might not be cross-platform, depending on device drivers for emulators and such.  TI’s Code Composer Studio V4 (based on Eclipse) only runs on Windows; V5 adds Linux.  MPLAB-X has beta downloads for Windows, Linux, and Mac).

NetBeans is primarily known for an excellent GUI builder, which typically isn’t important in embedded development.  I don’t know of any other companies using it for embedded development (or non-Java programming).  Even in the Java world, it’s been a distant second to Eclipse.

Eclipse has been used for non-Java programming (e.g. the C Development Tools or CDT) and embedded programming for a long time, and has many companies supporting it.  So Eclipse should develop a lot faster than NetBeans, and has the advantage of many more plugins.  Plus, Eclipse is run by an independent foundation, not by a company (Oracle) that likes to get paid.

Microchip is not very supportive of open source (unlike most ARM MCU companies).  On the good side, the PIC32 compiler lite version does not have any code size limitations; instead, Microchip removed optimization support.

Microchip is also a good source of low pin count chips, and is one of the few companies still selling MCUs in easy to prototype plastic DIP packages.  For example, you can get a 16-bit dspPIC33F with a CAN controller in 28 pin SOIC, QFN, and DIP packages.

I find Microchip’s mTouch Metal over Capacitor technology interesting: it allows capacitive sensing of metal buttons.

July 26, 2011   No Comments