Member Since: September 30, 2010

Country: United States




  • one nitpick: there’s no such thing as a non-addressable WS2811. the WS2811 IC is what makes it addressable. what you have there, and the correct datasheet you linked, is a RGB LED in the very common 5050 package. WS2812 use the same package and includes a tiny WS2811 IC to make it addressable.

  • they are not RGB. you could theoretically do RGB with charliplexing, but it would require using almost all the IOs of an Uno.

    I would expect red since that’s what the schematic and tutorial say, but I guess that could change in the future.

  • useful guides, some comments:

    for rainbow(), it maps 1-5 to 500-3000, and due to how map works, <1 and >5 will map <500 and >3000 in increments of 625. there is no bounds checking and its passed to delayMicroseconds() directly. since it’s unsigned int, you can’t have fractions, and <0 will wrap around and produce large numbers. sending 0 would give -125, and I’m not really sure what delayMicroseconds would do with that. maybe wrap backwards to the extend of an unsigned long?

    I’m somewhat surprised setRGB is using String instead of constant ENUM. that’s a lot of memory overhead for effectively no gain.

  • no, because piezo outputs AC, not DC. it should work no matter which way you wire it.

  • I recommend being more specific on the Ethernet line item. “Ethernet” means 10Mbit, “Fast-Ethernet” means 100Mbit, “Gigabit Ethernet” means 1000Mbit. after going to the wiki it appears this is Gagabit, which is pretty cool.

  • what exactly is in this? does it come with all the wires sticking out the side and what do they do?

  • SPI is type of serial connection.

  • the traces on the board are too small to handle much current. the warning assumes that if you’re doing something that needs more power than your typical LiPO then the board traces won’t handle it. however, if it’s high voltage but a tiny current it would likely be fine.

  • BealgeBoneBlack compares a lot better. it too can be powered from a lipo pack directly and integrates a battery charge IC. it’s not quite as power efficient at 2.3W peak and 1.05W idle, but it does have a lot more IOs including multiple UARTS and i2c and SPI buses, and PRUs that are accessible right now. And it has the USB, HDMI, and ethernet that some people want. And it’s $55, not including BT or WIFI. But really, your typical robot doens’t need BT and wifi , and often neither.

    the rPi is a fine cheap little linux desktop, but it’s really poorly spec’d in comparison to everything else out there. it’s cheap, and that’s really its only advantage.

  • keyboard and mouse? will there be a display block of some form? oled? lcd? hdmi?