Joe Knapp

Member Since: March 27, 2008

Country: United States

  • Product ROB-09571 | about 2 years ago

    I got it working with a Mega 2560 today without much trouble–Vcc at 6.0V from a dc-dc converter and tx/rx from Serial1 at 115200 baud. Having trouble though with the motor I’m using (from a Tamiya kit):

    http://www.robotbuy.ca/products/Tamiya_6_Speed_Gearbox-346-9.html

    http://www.mabuchi-motor.co.jp/en_US/cat_files/re_260ra.pdf

    When power is applied to this motor from a standstill, a current spike of several amps occurs for about 500 microseconds which is enough to cause the overcurrent protection on this device to trip. It helps to read and print characters from Serial1 to see the error messages (“ALERT 150” or whatever which is supposedly about 1.5A).

    Seems like it would be better if the firmware allowed greater current for a short period of time, so I’ll have to reprogram it to be usable in this application. Still though, I’d have the problem of stall (or high load) current of this motor exceeding specs. Maybe another device is in order.

  • Product BOB-08745 | about 3 years ago

    The input capacitance of the FET used is 55pF max, 40pF typical, so perhaps the 10K resistor (time constant about 0.5 microsecond) is what’s limiting around 2 MHz?
    http://www.datasheetcatalog.org/datasheet/siemens/BSS138.pdf

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