Where to stick VEX 393 IEM?

  1. 5 months ago

    Vyx

    Dec 7 Florida 33328A

    Where should I place Vex motor 393 integrated encoder module? I only have 4 and i'm not sure where to put them. Also are potentiometers, limit, and bumper switches preferable to this or are IEMs better?

    I second what others have said here. Let's summarize and add one note:

    for a limited range of motion, use a potentiometer. It is more accurate and precise and will not reset. It is also smaller and lighter.

    Encoders are great for the drive. It is best to use them on a free wheel that is not powered so you do not get slippage.

    Shaft encoders (quadratic encoders) are prefered to IMEs. IMEs take up less room but must be on a motor and though they are more precise, they are a lot less accurate than the shaft encoders. There has been a lot of discussion over the years about IMEs. They are very susceptible to static and other interference and you can get a lot of bad data from them. If it is all you have, then use them. We bought several a few years ago but will likely never use them again.

  2. Neil_6121C

    Dec 7 Pennsylvania 6121C

    You replace the green caps at the end of the motor with the modules. In my experience, using potentiometers or encoders is a much better choice because of the reliability of the reading.

  3. Vyx

    Dec 7 Florida 33328A

    @The Pioneers You replace the green caps at the end of the motor with the modules. In my experience, using potentiometers or encoders is a much better choice because of the reliability of the reading.

    Ah okay. My teacher talked about using a limit switch on the mobile goal lift so that it would back up too far. I think it could work because we just need a simple reading. Ill try adding encoders onto the drive train. Just have to make sure that there's enough space to fit the extra hump.

  4. Neil_6121C

    Dec 7 Pennsylvania 6121C
    Edited 5 months ago by Neil_6121C

    @Vyx Ah okay. My teacher talked about using a limit switch on the mobile goal lift so that it would back up too far.

    In my opinion, a potentiometer coupled with a PID loop might be a better choice because it will also let you bring down your mobile goal lift (assuming you use motor power to bring your lift back down) accurately as well as going up.

    @Vyx Ill try adding encoders onto the drive train. Just have to make sure that there’s enough space to fit the extra hump.

    It’s hard to go wrong with encoders on the drive train. Quick tip: if you put your encoder on an unpowered wheel, you will get far more accurate readings because the encoder will not account for the skidding of the wheels when you first power the robot from a stop, and therefore giving you the precise distance traveled of the robot.

  5. blatwell

    Dec 8 Event Partner Answer Indianapolis 621A

    I second what others have said here. Let's summarize and add one note:

    for a limited range of motion, use a potentiometer. It is more accurate and precise and will not reset. It is also smaller and lighter.

    Encoders are great for the drive. It is best to use them on a free wheel that is not powered so you do not get slippage.

    Shaft encoders (quadratic encoders) are prefered to IMEs. IMEs take up less room but must be on a motor and though they are more precise, they are a lot less accurate than the shaft encoders. There has been a lot of discussion over the years about IMEs. They are very susceptible to static and other interference and you can get a lot of bad data from them. If it is all you have, then use them. We bought several a few years ago but will likely never use them again.

 

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