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Member Since: March 14, 2010

Country: United States

  • For swap you’d do it the same as any other linux install. Either with a partition on the disk or a swap file

    dd if=/dev/zero of=/lin386.swp bs=1M count=2048  # Make a 2048MB swap file
    chmod 0600 /lin386.swp # set permissions for safety
    mkswap /lin386.swp # format the swap
    echo '/lin386.swp none swap defaults 0 0' >> /etc/fstab

    You’ll want to make sure you replace /lin386.swp with a file on the SATA drive whereever you have it mounted. The commands above will likely put it on the sd card if you’ve booted from that.

  • What you can do is use a lower voltage supply. Since the stall current of a motor is a function of it’s DC Resistance you can actually figure out what voltage you should run to get them just below the 4.5A limit:

    4.5A/4.9A * 12V = ~11V. If you make sure your motor supply is under 11V then you shouldn’t be able to exceed the max stall current of the driver board (I’d recommend 9V for safety and because it’s a common voltage). This does mean you’re limiting your maximum speed by about 25% (at 9V).

  • How sensitive is this board? I’d love to know if it could be behind some perspex or other plastic barrier and still pick up touches.

  • As with what bdcannon said, this means that your controller is never electrically connected to mains power, meaning that your controller is safe from being fried, and also that you are safe from being fried if you are playing with other parts of your project. It also helps prevent accidentally burning out a port on the MCU because you tried to sink/source too much current to the MCU. Definitely a big plus here. It also helps keep noise from the relays switching on and off from affecting other systems (assuming you have two supplies, one for the relays one for the rest of the system, which isn’t a bad idea if you’re going to do lots of fast switching).

  • I’ve been looking at this board quite a bit, and i’ve got one real question, is it possible to program this board from Linux?