shimniok is currently certified at Journeyer level.

Name: Michael Shimniok
Member since: 2007-12-23 16:33:37
Last Login: 2013-08-22 04:57:14

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Homepage: http://bot-thoughts.com/

Notes:

Author of Bot Thoughts blog, interested in robotics since '89. Since 2007, dove in full force, built Pokey the firefighter (failure = learning), and then Data Bus, 3rd place in 2012 AVC, my Rapsberry Pi tele-rover, a beam robot, and have tinkered with lots of other electronic thingies.

Recent blog entries by shimniok

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Making Test Jigs

Here's some cheap test jigs I use to test boards I sell on Tindie. Selling a quality product is of personal importance to me. With these test jigs, I've uncovered several board fabrication problems, more than several assembly problems (hey I'm not perfect), and identified ways to improve yield rate.

eeZee Power Jig

The goal for this jig is to measure 3.3V regulator output from the eeZee Power board. If it's 3.3V within the specified tolerance, that proves the regulator is populated correct, the USB connector is also populated, and all the corresponding traces are ok.

To build the jig, I installed pogo pins and test leads to an unpopulated eeZeePower board (to save time and money). When engaged with an eeZee Power, it enables the 3.3V regulator and connects the VCC and GND pins to the test leads. 

I plug a Mini USB into the DUT (Device Under Test), connect my DMM (digital multimeter) to the test wires and measure output voltage. 

Stacking another eeZeePower board would stabilize the pogo pins better. It's good enough as is.

eeZeePower test jig

AVR ISP Jig

This isn't a test jig, but one I use to program Turntable Strobes, Lost Model Alarms, PIPduinos, and other AVR-based boards. You can buy a fancier version of this on Tindie from BBTech.

AVRISP jig for programming AVRs
In case the picture isn't clear, one end has the familiar 6-pin AVRISP header, the other, pogo pins.

eeZee RGB Jig

I test every one of the eeZeeRGB WS2812B breakouts I sell to make sure the RGB modules are installed correctly and to ensure they work out of the box. I had been testing these with a breadboard Arduino but the pogo pins are unstable in a breadboard so I designed a test jig using an ATtiny85. I've discovered that some of these modules don't have reverse protection as advertised.

eeZeeRGB WS2812B breakout board
OSHPark builds boards in sets of 3 so I designed a single board that can stack 2-high (or 3-high if necessary) to stabilize the pogo pins. The Tiny and USB connector (for power) only has to be populated on one of those three boards. The other two boards can simply stabilize the pins. They're mounted together with screws, nuts and standoffs.



Test Jig, side 1

Test Jig, side 2

eeZee Prop Jig

The eeZee Propeller breakout (eeZeeProp) is the most complicated board I sell with a 44-pin QFP MCU, onboard EEPROM, crystals, a half-dozen resistors and capacitors, dual programming headers. I test every output pin on the eeZeeProp as well as programming functionality before it goes up for sale with this quick and dirty jig.

eeZeeProp test jig
The test jig above has two parts. The dual row of pogo pins, resistors, and LEDs is for testing pins. In the upper right is an FTDI programmer connector and pogo pins to engage the eeZeeProp FTDI pin pads. 

I program each board with a SPIN program that sequentially turns on each of the pins 0-28. The ability to program the chip in the first place tests P29-32 and the EEPROM.

Next, I lay the Propellers down onto the pogo pin bed and ensure each of the LEDs lights up sequentially. I can then investigate any suspect pins.

You probably noticed that the pins aren't well-aligned. My previous jig had two protoboards to keep the pins aligned better, but I broke it. Some day I'll redo this jig so I don't have to spend quite as much time manually popping each pin into place on the DUT.

Common Problems

You may wonder what kind of problems I uncover most when using these test jigs.

On the eeZeeProp I most often run into problems with connections on the Propeller MCU leads or the EEPROM. I've made some improvements in techniques that have reduced the frequency of these problems. 

While I very rarely found board fab problems on OSHpark boards (It's below 1% if memory serves, so reliability is very high), OSHpark is absolutely fantastic about fixing the occasional problem. 

I've seen far more frequent fab problems on a batch of Chinese made boards I ordered. I haven't contacted the supplier yet. The fab problems are mostly under-etching resulting in shorts to the ground plane. I may experiment with a wider isolation between ground pour and pads/traces and see if that helps any.

I've occasionally populated pairs of 0603 resistors rotated by 90 degrees. In future designs I'll try to avoid confusion by spacing the resistors farther apart. I've installed a diode backwards once or twice.

Syndicated 2014-09-30 14:20:00 from Michael Shimniok

23 Sep 2014 (updated 30 Sep 2014 at 05:15 UTC) »

Free Speech Synthesis For Your Robot

Newly painted Hero Jr.
I ran across a surprisingly good speech synthesis package. No, it's not Festival.

My Hero Jr had been painted blue, with holes drilled in the head, and other modifications. There's no better Hero Jr to modify and hack than this one. Possibly in time for the NoCo Mini-Maker Faire in Ft. Collins, Oct 4-5.

After painting it, the next step will be to add my recently purchased Raspberry Pi B+, or else the dusty PCduino in my closet, as a brain.

Then, implement speech synthesis. Vision: a robot "tour guide" for my Maker Faire exhibit.

While I adore the stock Votrax SC-01A speech synthesizer (it's the quintessential robot voice) I like the idea of a 20 year old robot with a modern voice even more.

Here's the fruits of my research so far...

Festival

I learned about the Festival speech synthesis system years ago. The now defunct Bot Thoughts podcast was hosted by the rab voice (UK). I thought it was the best of the stock voices, maybe because I'm not used to UK speech patterns and so the flaws aren't as jarring as those of the US voices.

The kal voice (US) is has a few digital-sounding artifacts in a few spots, and the intonation is noticeably wrong in several spots, too.

Other voices are available. The MBROLA US voices are decent. I also tried the enhanced CMU Arctic voices (download here). Here's rms.

rms_festvox.wav
rms_festvox.ogg

Mary TTS

Mary TTS is the package I ran across. Mary TTS is particularly linux friendly and comparatively amazing, primarily because it does such a great job with prosody (intonation, stress, rhythm in speech). Unfortunately it requires a lot of resources. It won't run on a Raspberry Pi.

This is rms, again, clearly the same voice (easily downloaded with a native Mary TTS tool), but... well, see how you think it compares.

rms_marytts.wav
rms_marytts.ogg

Admittedly there may be some tuning parameters in both packages that would improve the results. Out of the box, it seems pretty clear that Mary TTS does a much better job with pitch and timing.

Other CMU arctic voices are available for Mary TTS. I haven't picked out the right voice. I kind of like Poppy, the female British voice.

Free TTS

I also came across Free TTS, also written in Java. Unfortunately, based on the samples I heard, the prosody is pretty poor compared to both Festival and Mary TTS.

Others?

Any other tips on free speech synthesis packages out there?

Syndicated 2014-09-23 12:10:00 (Updated 2014-09-30 04:22:19) from Michael Shimniok

Hero Jr Repaint

Ruining things sucks. I kinda screwed up and my impatience got the better of me. 


I didn't really care for the dark blue Hero Jr. I preferred the original computer beige and burnt sienna trim. So I "fixed" it... I fixed it real good...
I was going to be lazy and just paint over the blue with a nice heirloom white. But no, I decided to use Citristrip on one of the panels and of course I was too impatient to test it on an inconspicuous area. So the stripper works really well. I highly recommend it. But not for plastic. It'll eat plastic. So I found out.

Long story short, the stripped panel will become the back panel, as it's kind of hashed up from me scraping off gooey paint and plastic. I may try sanding it more. It's not too bad. You can't really tell unless you're really close up. You win some, you lose some. 

I picked satin paint for a very good reason.

The plan is to do the trim in aubergine. I am very likely to give the robot a female voice. I think my little girl will like that better than a male voice.

Syndicated 2014-09-16 15:13:00 from Michael Shimniok

12 Sep 2014 (updated 16 Sep 2014 at 00:14 UTC) »

Back to Linux Mint... 13

I installed Linux Mint 17 and have switched back and forth between Mint 14 and 17 for awhile due to instability in 17. I'm using the same home directory I had on Mint 14 which might explain it.

Yesterday, Thunderbird and Chrome kept repeatedly crashing until I logged out and back in again.

The entire computer hung at another point; I couldn't log in remotely, move the mouse, do anything with the keyboard (numlock etc).

At another point, the kernel reported some kind of error/crash/panic/something--can't remember as I was juggling several things at once.

And a few weeks ago, video was going wonky after waking from sleep (I believe they've gotten this known issue fixed since then)...


I fully expect all of these issues to be resolved in the coming months. Meanwhile, I really need two things. First, a stable Linux environment. Second, a supported environment so I can install and update packages, like Festival speech synthesis.

So Mint 17 is gone, replaced with Mint 13 LTS (Long Term Support), based on Ubuntu 12.04; it will be supported until April 2017.

Mint 13 appears to be rock solid so far, zero issues. There are some under-the-covers differences; I couldn't change desktop settings until I nuked the newer config directories. Minor issue. I may be stuck with older versions of some packages, we'll see. And Nemo file explorer didn't come out until Mint 14, but that's ok.

In another month or so I'll give Mint 17 another go and if it's not behaving better I'll try to spend some time reporting bugs.

Syndicated 2014-09-12 14:31:00 (Updated 2014-09-16 00:07:18) from Michael Shimniok

20% Off Labor Day Sale at Bot Thoughts

Get 20% off most items with coupon AF954E4 in the Bot Thoughts store. Thursday through Labor Day. ATtiny prototyping, Parallax Propeller breakout, microSD breakout, RoverMux, and eeZee Power breadboard power supplies.

Syndicated 2014-08-28 12:25:00 from Michael Shimniok

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