I have not written here about Magic: The Gathering, a collectible card game that I have been playing for about a year and a half.  It started in my workplace, that was, at one time, very active with MTG players.  One co-worker decided to revive interest by sponsoring a draft tournament, with prizes, for the small entry fee of $10; less than the retail cost of the cards we received.  I played and lost, but I got hooked on this wonderfully flavored game with complex interactions!  I even sponsored one of our “Lunchtime Magic” tournaments!

Lunchtime play died down at work, but I got my sons interested, and we started playing at home and at our local game store (Friday Night Magic® tournaments).  I now have a few THOUSAND cards, and various peripheral paraphernalia.  I’m even looking into playing formats other than “Standard” that I have played exclusively since I started.

So, since this has become one of my major hobbies (alongside electronics/microcontrollers), I will probably start posting a story about MTG once in a while.

Here is one of my favorite decks.  It doesn’t win much, but it’s fun to play.

Standard Elves

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Creatures (27) 2 Ezuri, Renegade Leader 4 Nissas Chosen 2 Ezuris Archers 4 Joraga Warcaller 4 Elvish Archdruid 2 Copperhorn Scout 4 Llanowar Elves 2 Fauna Shaman 3 Tel-Jilad Fallen Spells (15) 3 Naturalize 3 Strength of the Tajuru 1 Asceticism 2 Gigantiform 2 Quest for the Gemblades 2 Genesis Wave 2 Overwhelming stampede Lands (18) 14 Forest 4 Oran-Rief, the Vastwood Sideboard (15) 1 Nissa Revane 4 Arbor elf 2 Tajuru Preserver 1 Tel-jilad fallen 2 Ezuri’s Archers 2 Fauna Shaman 2 Plummet 1 Strength of the Tajuru

(Sorry about the missing apostrophes, the plugin errors on apostrophes in card names.)

This is hilarious and educational, all at the same time!  For those who don’t get how pointers work, this clears it up:

I noticed I was doing a lot of breadboarding at my desk (as opposed to my worktable in the basement).  That was fine, but I always had to have a battery pack/power supply hanging off of the breadboard.  I had this neat enclosure I got as a sample that has a battery compartment.  It’s made for AA batteries, but two 9v batteries worked fine (I put electrical tape over the other contacts).  I built two power supplies (5v and 3v) on a project board and mounted it inside.

I soldered some leads to the underside of the breadboards, then wired up some switches and power LEDs

I made the 5v (green) LED brighter because I wanted to be sure I noticed that there was a higher, potentially damaging voltage on one of the power rails.  I put a few other safety features in place, such as diodes between the positive terminals of the 9v batteries (in case I put one in backwards), diodes on the ground rails (to prevent unwanted circuits through the power supplies), and disconnection of the power rail(s) through the switch(es) to completely isolate them when the switch is off.

Here’s the schematic:

Let me know of any errors in the comments.

STMicroelectronics has a new “evaluation board” for its “value line” of STM32 microcontrollers, priced at “under $10″.  (Product page) This seems to be a follow-up to its little brother: the STM8S Discovery board: (Product page) STMicroelectronics seem to have ceded the 16-bit hobbyist market to TI’s MSP430 LaunchPad (Product page) which, at $4.30 is the most inexpensive evaluation board I’ve seen offered for any microcontroller.  Despite STM’s claim of “under $10”, the STM32 Value Line Discovery board is selling at Mouser for US$11.85, and at Arrow for 13,16 EUR.  The STM8S Discovery board can be had for US$9.60 at Mouser (up from ~US$7.20 release price back in November 2009).

The STM32 Value Line Discovery board has many familiar features to the MSP430 LaunchPad crowd.  There is an integrated USB programmer/debugger, two user LEDs, a user button, and a reset button.  All of the uC’s pins (plus some others) are broken out to headers along the edges of the board.  There is a free programming tool chain available, as well as several example programs.

Despite many similarities to TI’s LaunchPad, the STM32 Value line Discovery board (and the STM8S Discovery board) have some distinct differences.  The processor on these boards is a surface-mount type and thus, soldered on.  The programmer/debugger cannot be separated from the uC, physically or electrically (except, in the case of the STM8S Discovery, by snapping the board apart).  The STM uCs also seem to require several external components for operation; rather inconvenient if one is accustomed to the self-contained MSP430.

The STM32 is, however, quite a capable uC.  I didn’t grab all the specs, but the family is listed as being: “An advanced ARM-based 32-bit MCU with 16 to 128 KB Flash, 12 timers, ADC, DAC & 8 comm interfaces.”  Now, the specs I did see on the STM32F100RB chip on the board included 7 16-bit timers plus some specialty timers, 16 12-bit ADCs, 2 12-bit DACs, 2 SPI, 2 I2C, and 3 USARTs.  In lowest power mode, it can run on 1.7uA.

If you need this kind of power, the STM32 Value Line Discovery board is available now.  Me?  I’m sticking with the MSP430 LaunchPad.  It’s plenty powerful enough for me, and I like being able to remove the uC from the board and use it in my own circuits.  Now, if TI would just release those 20-pin models; I could use the extra I/O pins!

The lower pull-up resistor value helped (I got better range when I tested it on a breadboard with a single side of the sensor), but I think wiring both phototransistors in parallel cut back on the resistance through the sensor as well.  For this reason, I would suggest using a mouse-style dual IR sensor wired in parallel if you choose to try this project.

I went to a tire store and got an old trash inner tube for free. I cut a strip of rubber, cleaned it, and super-glued it into a loop to fit around the meter. I punched a hole with a nail and fed the wire (from the same old mouse where I salvaged the phototransistor) through the hole; it fits water-tight. I decided I might as well use both of the IR phototransistors in the unit, so I soldered three wires to it and super-glued it in place at the right distance from the edge. It fits pretty well!:

I bought a PVC conduit corner piece similar to the larger ones connecting to my meter and feeding into my house. I cut the back connection off, and sealed the back hole with scrap rubber and super-glue. I also used some rubber over the bottom opening to feed the wires through (and keep spiders out). I put a small strip of 1/4″ plywood inside, super-glued a terminal strip to it, and ran screws through the terminal strip, plywood, and rubber and out the back hole to mount to the house.

I ran a piece of CAT-5 cable through an existing hole in the side of the house and into my basement, where the microcontroller and computer will be. The CAT-5 and the terminal strip give me eight conductors in case (when) I run more sensors outside.  I did have a setback that the screws on the terminal strip are ‘cupped’ underneath, so they kept cutting the thin solid CAT-5 wires.  I solved this with a pair of washers per screw.  The only sensor connected so far is the IR phototransistor for the meter (top two terminals on right).  I forgot to get a shot with it all closed up, but it fits visually with the other utility conduit and boxes around it.

I have tested the connection inside, and I am able to detect the pulses on my DMM (drops to ~5 ohms) and with the LaunchPad (triggers an interrupt reliably).  Next up: Firmware and software. More when I get it running!

I added a mobile theme (coincidentally named “Mobile Theme” – link in pic) because I was tired of my blog looking like crap on my Android phone.  I’m not sure if anyone else will use it, but it was bothering me quite a bit.

The theme should kick in automatically if you visit through a mobile browser.  Let me know in the comments if you have any trouble.

TI’s MSP430 LaunchPad is growing a great community, and along with it, some opportunities.  Joe over at http://joesbytes.com/wordpress/ recently sent me a sample of his new LaunchPad Mini Proto Board; a handy prototyping board similar to an Arduino prototyping “shield”.  You can buy the boards on his site for $6 with free shipping.  Joe even makes the Eagle files available, but I doubt you can fab it for less than $6 shipped! 

The board is currently only available as a bare board, so you’ll have to supply the parts to populate it.  This is a much more compact method if you only need a small breadboard or prototyping area.  (If you want a full breadboard, see my LaunchPad Breadboard Adapter.)

This is a high-quality, well thought out board with a few simple extras that make it great.  Most of the board’s space is a prototyping area that is thoughtfully perfectly sized to fit one of SparkFun’s mini breadboards.  All of the LaunchPad’s 20 pins are brought in to headers next to the prototyping/breadboard area.  The Vcc and Gnd lines are broken out into extra headers; both Vcc and Gnd are available on three sides, and there are holes for extra decoupling capacitors next to the headers on two sides.  A nice extra is the provision for two on-board LEDs with accompanying resistors, attached via dedicated jumpers to P1.4 and P1.7.  The silkscreen is excellent, with every pin and part well labeled.

The mini proto board’s dimensions are just a bit shorter than the LaunchPad, coming up exactly even on three sides when assembled and attached.  The LaunchPad’s buttons, LEDs, and external power header are accessible with the mini proto board attached (though the extra Gnd on the power header is a bit tight).

Assembly was easy, as all the parts are through-hole.  I chose to have some of the power headers female, and some male.  I did have to sacrifice the female headers that came with my other two LaunchPads because the female headers I ordered haven’t arrived yet and I’m impatient!  I chose blue and white for the LEDs since the LaunchPad already has red and green.

Here are a few shots of my finished board:

The only glitch I had was that my resistors seem a bit longer than the board is designed for.  I popped on a couple of jumpers, and tried out my “police light” program.  The flashing blue and white LEDs look great.  I’m going to order a mini breadboard right away.  You should order your LaunchPad Mini Proto Board now!

My circuit boards arrived, and they are beautiful!  The quality on these boards is outstanding.  I will definitely be ordering through DorkbotPDX again.  You can see that the cuts are perfect (with small, perforated, easy to snap tabs!), the trace, drill, soldermask, and silkscreen are perfectly aligned, both front and back.

So, why the odd title to the post?  See if you can spot what’s wrong with these pictures:

Yes, that’s right; the fab house made them exactly as I designed them!  (Not how they should have been designed…)

I did measure twice… well, at least on the LaunchPad breadboard adapter…  The problem was that I did not do a final measurement check before I sent off the order.  In the midst of making things look decent and work properly, I somehow made the LaunchPad end of the adapter 0.1” too wide.  The power supply I probably made to fit the extra space and intended to adjust the size before sending, but forgot.

C’est la guerre!  I may be able to salvage these boards (lots of empty space on the power supply, and maybe some angled pins for the adapter), but I have learned a lesson:  Always double-check the “Final” plans.

(BTW: I will post the corrected Eagle board file here once I fix it.  The “mini-LaunchPad” portion will not be included; I’ll post that another time, once it’s proven workable.)

EDIT: Eagle board file (fixed?)

One of the main reasons I wanted to learn microcontrollers was that I wanted to make my own energy consumption monitor.  I live in the US, and I have an Itron digital electric meter on my house.  On the top of the meter is a plastic optical conduit that goes to an IR LED that flashes once for each watt-hour used.  I was hoping to use an IR transistor to read the meter flashes with an MSP430, and pass the info to a host computer (probably an old junk laptop I have).  Once I had the meter-reading done, I could start considering weather sensors and appliance sensors to see how they affect the electricity usage.

So, I tried wiring up an IR sensor (one side of a dual-IR phototransistor salvaged from an old ball mouse) and hooking it up as I would a switch on an input pin.

I ran a test program, aimed an old VCR remote at it, and voila!  It worked!  While still jazzed about this, I took the LaunchPad outside with a battery pack, and taped the IR phototransistor over where the IR flash should be… nothing.  I turned on the air conditioning to be sure I was using a decent amount of energy… nothing.

I finally broke out my cell phone camera and tried to see the flashes.  At first, I thought my meter didn’t flash.  Then, I put the camera up close.  It wouldn’t focus, but I could see the flashes (please excuse the noise from the A/C unit):

Too dim for my set-up.  I need to either find a more sensitive sensor, change the circuit to amplify the signal (an o-scope would be nice!), or can this idea.

Any ideas?  I would love your comments.