Member Since: January 14, 2011

Country: Netherlands


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  • It’s just the serial I/O clock pin - google around for miso / mosi / clk / cs for details on how you’d use it, but it’s nothing to do with the GPS timestamp :)

  • For the curious, sgrace is an FPGA wizkid and has previously written So You Want to Learn FPGAs….
    Also check out Digilent’s resources

  • If that sort of thing has your interest, I’d say hit up YouTube. There’s quite a few channels on there that do almost nothing but tear downs of LED lights and other cheap electronics. bigclivedotcom, Julian Ilett, electronupdate, etc. Bigclive especially tends to go over the boards, draws up a quick schematic, etc. At this point, though, all of them tend to be very much the same with only minor changes in passive or the odd change to a new driver IC.

    From several of those channels, the ‘LED filament’ types are getting pretty good reviews. I think Mike’s Electric Stuff recently picked some individual filaments up and made a clock display with them. I’ve had one for a few years now (ali) and it’s definitely been holding up fairly nicely - certainly better than most of the GU10 spots :)

  • My memory doesn’t go back four years on these topics, I’m afraid - but google+hackaday does: a stackable motor driver shield for the arduino

  • If the Eagle files are right, then 0.9" (22.86mm) by 0.68" (17.34mm). No idea about thickness - but could probably guesstimate that based on standard board thickness, the header and the mini USB port.

  • While not necessarily an accurate net value the weight used for shipping calculations (can be found in the json/csv, top right corner of the page) suggests 0.7692lbs (~350g)

  • cheap perfboard with a window cutout makes for a quick and easy front panel :D
    I suspect the headers are more for access to pins for testing, and if you’ve got umpteenthousand stackable ones in inventory, you might as well use them ;)

  • I fully understand. In this case, though, the intended availability of a BOM was mentioned in the KickStarter project:

    The MicroView is Open Source Hardware, this means that we’re making the design files for our enclosure, printed circuit board, bill of materials and software libraries open free to download and use.

    KS:MicroView - Update 1

  • Judging from the close-ups: columns (short side), zig-zag (serpentine)

  • The emitter is the only one that you should worry about with powering. That one is a very sensitive little IR emitter. If you look at Figure 4 in the datasheet, you can see the curves for forward Voltage vs forward Current. You can see there that changing between 1V and 2V incurs a change between ‘1'mA and 300mA - well into the range where it would fry.

    Rather than driving it by voltage, you should drive it by current. There’s a couple of figures in the datasheet (some of which - test condition at 7mA - make me wonder if they typo’d something), but if you scroll down to page 7, you can see SHARP’s design recommendations which state that forward current should be between 10mA and 20mA. So in your design you should try to make a ‘constant’ current regulation for 15mA. This can typically be done using just a resistor. Going back to figure 4, for 15mA the forward voltage at room temperature is - guesstimating - about 1.13V. (That iffy part of the datasheet lists 1.14V, so at least that’s a bit of confirmation). After that you can use any normal LED calculator to find an appropriate resistor for your given supply voltage. SparkFun’s breakout board for this component for use with an Arduino 5V uses a 220Ω resistor, but notes that 330Ω works as well. That would fit with my calculation (ends up at 270Ω) as well.

    The detector side is much more forgiving, taking anywhere between 4.5 and 17V according to the datasheet. In SparkFun’s breakout board, this means it’s just hooked up directly with the detection pin going out to - in their case - one of the input pins on an Arduino. Note that most of the test conditions on the detector side are at 5V, and I certainly wouldn’t actually drop 17V on it :)

    Hopefully this should keep the other one from burning out on you - make sure you check all the connections, have a peek at that breakout board too :)


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The kind of wish list that gets you in trouble