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Question on the L298 - Page 2 — Parallax Forums

Question on the L298

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  • morris4019morris4019 Posts: 145
    edited 2009-06-03 17:05
    My motors are GM9 Gear motors bought from Solarbotics. Yes there is quite a bit of force required by hand to start these motors. But, when using say, the L298 to put on a 'brake', you cannot move them. These are some pretty tough motors. I've attached the solarbotics spreadsheet that contains the gear ratios and other usefull info about their different motors. Mine are about half way down, GM9.

    -mike

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    ······ I'll try everything once [noparse]:)[/noparse]
  • TimmooreTimmoore Posts: 1,031
    edited 2009-06-03 17:34
    I haven't used those but I have used other motors from that range without problems. Its unlikely thats the problem with both motors - with 143:1 makes the motors hard to turn, though if you have a 100ohm pot you could try them by putting 6V across the pot and connecting the motor between the variable and ground. The motor should change speeds as you move the pot.
    Another thought, where did you get your pwmx8 code? Phil fixed a bug after the initial release to do with using pins that start from not pin0. Look in the header of the file and see if you have a line "' Version 1.1: 17 Jul 08: Fixed a couple bugs related to base pins > 0."
    If not and your pwm is connected greated than pin 7 it may be that. I think the latest code is on obex.
  • morris4019morris4019 Posts: 145
    edited 2009-06-03 17:39
    It does not have a Version 1.1, but the like "17 Jul 08: Fixed a couple bugs related to base pins > 0" is on there.

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    ······ I'll try everything once [noparse]:)[/noparse]
  • mikedivmikediv Posts: 825
    edited 2009-06-03 18:18
    morris4019 I can not really tell from your pictures what type of motors you are using but if they are just simple DC motors not steppers or servos like the ones used to run RC cars then you might want to try the
    ULN2803 I have been using it for all sort of motor control but I am now using to run 2 radio shack 1.5-3 volt DC motors part number Radio Shack 272-223 we use them to build
    tiny dragsters and we race each other we made up rules everyone has to use same motor, MCU/Prop, wheels and frame but you can use whatever for the guts and I ended up using the ULN2803 its very simple
    to use and there are lots of schematics on internet, maybe that would help??? if you want to see my schematic and code just let me know it will also run backwards and you can drive 6 of these dc motors with one 2803
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