measure motor friction

[finneykris]

Hi,

how can I use the NXT to measure the friction of a motor, this is useful if a gear geats jappned when swapping over or if the car hits a wall but tries to spin the wheels.

with the output port it does not seem possible. and you cannot use input port with the motor.

if a certain value is read (meaning too much friection) then something will step in such as a motor allowing a white echnic clutch gear to step in and do its stuff.

at the minute im concerned about the hardware setup not the program to get it to do it.

maybe im wrong and a pin on a NXT output port can be inout too.

im not sure if it is friction or torque.

[inxt-generation]

If I understand correctly, you want to be able to tell when a motor is blocked, or when it's outputting too much power, correct? There are several ways to do this, but first of all, what programming language are you using?

[pepijndevos]

One of them is checking the overload field, which is true when the motor is not turning as fast as requested.

[mattallen37]

One of them is checking the overload field, which is true when the motor is not turning as fast as requested.

I'm fairly sure that only goes for certain types of motor control.

Basically, you should have a desired rotation speed for all the PWM settings (assuming you're using just PWM and direction control). If the motor is moving significantly slower than it should be, it's likely that it has physically run into a limitation.

[finneykris]

I am not sure on what language to use yet, its just if the power goes up too much not if it goes slow, it has several speeds that can be set.

if if pwm works best for what I need then ill probably use that but I still do not get if the pins on a NXT output port can input information or if an input port can output information else how would the NXT be able to get the readings.

note that Im using a motor with no reduction gears.

[mattallen37]

The NXT motors have built-in encoders (for position feedback). To have access to the encoders, you just need to connect the NXT motor to a motor port of the NXT, using a standard NXT wire (6 conductor). So yes, the motor ports do have input pins (5 and 6).

[mcsummation]

note that Im using a motor with no reduction gears.

What motor are you using?

[finneykris]

I think ill be using this: or

[pepijndevos]

These definitely do not have encoders in then. But I just found this: http://botbench.com/blog/2012/03/22/com ... lidewheel/

[finneykris]

how about using another method, I think the encoder method is going to take up too much space in my model, and it is not out for purchase yet.

also are pins 5 and 6 the yellow and blue ones since the NXT cable and connector goes with the latch facing up ontop?