Member #466449

Member Since: September 2, 2013

Country: Argentina

  • Flyback diodes can be useful to avoid the 20V, 50V or probably even 100V spikes due to the motor’s inductance. As you most likely know, they are meant to be wired in the opposite way as the power supply (i.e. positive to cathode and negative to anode).

    Now the problem is, if you want to reverse the motor’s rotation, you have to reverse the polarity. If you reversed the polarity, the diode wouldn’t be wired in the correct way anymore, and would instead short out the power supply anytime the motor was on.

    And if your power supply was not current limited (e.g. LiPo batteries without protection circuitry) you would most likely set things on fire.

  • Maybe you can implement an automated script, that if someone posts 3 or more identical comments, it would disable that user’s account. After say 24 hours or even better 3 days, it should re-enable it, but if he/she keeps spamming it should disable it permanently.

    I say 3 or more and not just 2 because some pairs of products, such as the Cool White and Warm White 3W LEDs (COM-13105 and COM-13104 respectively) both have the same error in the description or somewhere else.

    Or maybe just use a captcha-like verification code when registering an account. Or both. Even though that would be annoying for legitimate users, it would hopefully reduce spam.

    Anyway, the main reason why I posted the first comment was to get an answer on the size and price of each of the solar panels you used, so could you please answer that question? Thanks ;)

  • The spam comment I was talking about got deleted. But now as I type this there is another one! Thanks for the suggestion, I reported it already.

  • So, each panel generates 327 Watts, but how much did they cost and how big are they? Because you guys sell a 18x22cm (~0.04m²) panel that produces 5.2W and costs $44.95, so at that rate a 327W would most likely be about 60 times as big (maybe 1.5m on each side?) and cost about $2800. Please tell me I’m wrong.

    On a completely unrelated note, can you please delete “spam bot” accounts such as Member #644538, who commented here, and about 10 others I have seen in the past but obviously can’t remember their IDs? It pisses me off when I want to read comments in your blog posts and I see spam.

    Oh, and if you don’t delete the accounts, but those users ever buy something from the site, which I highly doubt, send them something completely different to what they bought, preferably damaged parts, and ignore customer service calls/emails from them. lol, just kidding, but actually, why not? ;)

  • I tried this under Firefox, and it looks kind of buggy with what seems like redrawing problems. Under Chrome, however, it works pretty well (sometimes it lags but it might be my computer). I find this annoying because I use Firefox most of the time, so it would be great if you could fix that.

  • They’re carrying them now!

    Switch: https://www.sparkfun.com/products/13253

    Breakout board: https://www.sparkfun.com/products/13098

  • This product has been retired from our catalog and is no longer for sale. This page is made available for those looking for datasheets and the simply curious.

    Which datasheet? You never got a datasheet for this product ;)

  • That’s funny because it’s currently out of stock and there is no ETA.

  • Even if you could connect ONE of these to a computer via serial, you’d be very limited in terms of either refresh rate or color depth.

    At 115200 baud, if you were driving it at 3-bit color depth (where you only have 7 basic colors, that is, blue, green, cyan, red, violet, yellow and white), you’d get 37.5 Hz refresh rate, which is pretty good, however you don’t use the full color capabilities of the matrix; but try to use even 12-bit color depth and the refresh rate will drop dramatically to ~9.4 Hz, which sucks, because the display would flicker too badly.

    Try to do something similar to what’s suggested on the tutorial recommended above, you’ll actually need a micro (specifically a Teensy 3.1) but as far as I know it’s the only way to hook one up to a computer.

  • Well, the datasheet says there is a 9uS Low-high propagation delay, and 15uS High-low propagation delay.

    If you add them together you get 24uS, or a frequency of 41.67 KHz.

    36 gaps per revolution gives you 0.6 (36/60) Hz for every RPM.

    So assuming your micro is fast enough, this could, in theory, work all the way up to ~70,000 RPM, but don’t expect great accuracy at those speeds (read below)

    If you need very high accuracy, it actually won’t work. For example, the Arduino’s micros() function has 8uS resolution. So let’s say you have 400 uS between 2 detected gaps. In that case, your code should convert that to 4167 RPM. However at 392 uS/gap, you’d get 4252 RPM; or at 408 uS/gap, 4085 RPM, both of which are probably huge differences, depending on what you’re planning on using this for.

No public wish lists :(