Member Since: January 14, 2011

Country: Netherlands


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  • 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 :)

  • Yessir -

    with the same connections to pins and power rails.

    It’s difficult to see in the photos, but if you check out the Eagle design files, you can check exactly which bits are connected together: imgur.com/UwPCABR

  • For people who are curious - some graphs:

    ( There were supposed to be some in an Arduino Day 2014 post-mortem as wellhttps://www.sparkfun.com/news/1439#comment-5336fcca757b7f684a8b4567, but Google’s not finding it for me. )

  • Comments are sorted by number of stars and recency, in that order, per level. So right now your comment has 1 star, which puts it below all the 4-, 3- and 2-star comments. It’s also the most recent, which puts it above the older 1-star comments. Don’t worry, your question will still likely be seen by people who know the answer :) I’m not one of those people, though - I’m one of the people who wonders if you’re confusing this product (a driver board) with a different one (chassis), but might be inclined to point to http://forum.arduino.cc/index.php?topic=82618.0 mentioned in the 3-star comment :)

  • According to a comment in the Uno R3 (PTH) product page, it would be the official Arduino Uno boards, not clones.

  • That’s Enclosure - Flanged (Red)

  • Mint tins (Altoid - thanks 1oz!), cigar boxes, match boxes - have often served as enclosures. There’s enclosures in lots of things you buy as part of groceries (though increasingly less so, as they’re reducing plastic use making many too flimsy). SparkFun’s red boxes have been used as enclosures (a dedicated SFE parts box was not commercially successful enough to continue, possibly because the default shipping boxes were eating into that in the first place ;) )

    But yes, sometimes a dedicated box just works out a lot better. It’s just unfortunate that there appears to be no system to these enclosures' sizes except when they target a specific already standardized application (DIN rails, for example, but also eurocard, half eurocard). There’s plenty of standards (NEMA, IP)regarding the materials used, how well they keep dust/water/etc. out. But sizes are all over the place, and often there doesn’t appear to be any relationship between enclosure X, and enclosure Y which from the manufacturer is the next size up (example: Polycase LP11P: 2.5x2.5x0.9", LP21P: 3.29x2.42x1", LP31P: 4.17x2.8x1", LP41P: 3.29x3.29x1.25"). Sick of Beige also hasn’t caught on as of yet.

    Back in the 90’s there was a local company that sold plastic sheets with a 1cm grid of 90° v-scores. These could then easily be cut into typical box folding layouts, folded, and glued or (with appropriate standoffs) screwed shut. Far from ideal as far as structural integrity goes, but it was probably the least arbitrary system I’ve seen.

    With that lack of standardized sizes, combined with a lack of standardized PCB sizes in the first place (few design for a standard size, let alone stand-off offsets) it’s really not surprising that people get creative when it comes to finding enclosures - even if not sharing Dia’s “Everything Is An Enclosure”-perception of the world :)

  • SparkFun Ding & Dent sales graph

    What a difference a newsletter makes :)

  • No problem :)

    And yes, that does appear to be the issue. Though apparently not a mistake, as the person who made the modification very specifically states that the change ‘fixed’ something. I don’t know what was broken about it, but there you go: commit 32d88ec02745a1d2afb5086dba467882986325a8: Fixed the frame-letter thing again.

    However, that just wraps us back around to my original comment, which I’ve given a new step-by-step, start at Step 8 or scroll down to Step 8b directly: imgur.com/a/2uMK5


Kamiquasi 16 items

The kind of wish list that gets you in trouble