Member Since: January 2, 2009

Country: United States

  • You need thousands of dollars of gear to assemble 0.5mm SMD parts reliably and professionally. Many hobbyists are happy to pay $20 per board to not have to deal with that themselves.

  • Bonus points for airborne.

  • What grade of caps does this use? X5R/X7R+?

  • Rumor has it, no chips until June or so.

  • Are you guys getting more of these? They're nowhere to be found.
    And combined with the HMC5843 EOL.. it could be a tough couple months for UAV nerds. :-\

  • Yeah, I had the same problem with my BTM-182. Apparently the BC04 UART_TX is not really push-pull; it's some kind of open collector/tri-state driver with a weak pullup: http://www.oemblue.com/download/BC04Class1Module.pdf
    1.5V is really marginal for Vih on a 3.3V micro, let alone a 5V micro. But since its not a push/pull driver in the BTM, you just need to add an external ~1K pullup to 3.3V, or if you are cheap/lazy, enable on the internal pullup inside your micro.
    The internal pullup in my 5V ATmega48 brought the pin to about 3.8V, which is a solid logic '1', and now it's working for me.
    3.8V is technically 0.2V above spec for the BTM-182, but I doubt it will harm it as there's virtually no current flowing.
    In the MCU->BTM direction I am using a resistor divider to drop the level (390 / 680 ohm for 5.0 -> 3.3V).

  • This violates the USB electrical spec by driving 5V onto D+/D- (they are 3.3V signals). USB hosts are required to withstand 5.25V on D+/D-for up to 24 hours -- but not indefinitely. Might be wise to connect this through a $5 USB hub instead of directly onto your $2500 iComputer. Or, add dropdown diodes or a proper 3.3V Vreg for the AVR.

  • The GS406 is superb once you've ghetto-soldered wires onto it. It'd be the freakin UAV GPS king if it had a con that mated with something that's not out of stock at every disty on earth. Anybody want to group buy a reel with me? 1,998 left :P

No public wish lists :(