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Member Since: May 21, 2008

Country: United States

  • FYI it is hard to find the high side current sense IC because the schematic label is not the manufacturer part number. ZXTC1009 datasheet http://www.diodes.com/datasheets/ZXCT1009.pdf . I believe is the chip or its equivalent.

  • Sparkfun uses EAGLE which is free for viewing any design, you just have to buy in to "make" bigger higher layer count boards. That's understandable. The guys at Cadsoft gotta eat too. Additionally if you just wanna do home development a standard license is only $125. That's nothing compared to Altium or Mentor Graphics etc.

  • According to the datasheet of the atmega8u2, when you operate this board at 3.3v you must run using the internal oscillator. VCC should exceed 4.5V to be run at 16MHz.

  • I may be wrong since I've never used relays before, but if you look at the datasheet the amperage required to turn on the relay goes up with lower voltage. for 5v the current is 80ma and would be likely as much as 100ma for a 3.3v relay. That much current will fry most any microcontroller pins, especially low power 3.3v devices. You need to use a transistor or mosfet to source enough current. The voltage on the relay input is then pretty immaterial.

  • "How much anchoring do ya need?"
    well if this were to go on the bottom of a robot. 3 or 4 mounting holes would eliminate the risk of large bending moments. if a robot with this hits something, the trackball board will likely snag, and possibly snap.

No public wish lists :(