NXT motor: use as an encoder with removed motor?

[HaWe]

no, what I meant in my TO post were the NXT encoders inside in the motors.
The Tetrix encoders have to be attached directly to the HT Tetrix motor controller, no way to attach them to a NXT motor port.

So I'm looking for (any) encoders which can be directly plugged to the NXT motor ports (without soldering), e.g. just the NXT encoders without motors.

[mattallen37]

And what I am saying, is that there should be a way to easily use the tetrix encoders with the NXT motor port. You said that there is no way to get the encoder values from the controller, so I assume you want a way to monitor the value through the motor ports of the NXT. The tetrix encoders should be electronically compatible with the NXT motor ports.

If you don't want to do any soldering/adapting electronically, sorry, but I don't know of anything that will help you.

[HaWe]

Now I understand what you mean, I could try to connect the 4 Tetrix cables (yellow, blue, brown, red) somehow with 4 of the 6 NXT cables.
How would you suggest to do it?

[mattallen37]

I really cannot guarantee anything. If I were to try this, I would determine gnd and vcc for the encoder, make sure the encoder is rated 5v, and connect the supply lines to supply of the NXT port (pins 3 and 4). The other two (signal wires) I would connect to pins 5 and 6. The order of these signal wires does not make a difference to functionality, only to the direction of count.

[HaWe]

I don't know which Tetrix cable color has which functionality, there is no documentation about it to be found (at least I didn't find any).
If it was easier to take the encoders from the NXT motors, then I would prefer to use them, because they are already correctly soldered to the motor plug.

[mattallen37]

Test it; that is the only way I would be able to know.

Electronically, yes, it probably would be easier to connect the NXT motor encoders. Mechanically, it would be like trying to make an encoder from scratch (like Philo did), or even harder.

If I were to do it, I would definitely test the wires. It should be very easy, even with just a volt meter.

All I can say, is you should try. Try some of this on your own. I am just as much in the dark, stabbing around, as you are, and I don't have the HW to test it like you do. Venture out a little.

[HaWe]

I don't have the facilities to test out something like that, it's integrated components and they are too expensive to risk destroying them by braking them out and test them (each encoder >100 EUR plus 19% tax plus 20% customs plus shipping)

so better we return to the TO question:

using the NXT motor passively driven just as an encoder is giving a high drive resistance
- anyway, the advantage doing this is having a very quick encoder without losing a sensor port for each motor encoder.
Has anyone tried to remove the motor out of the housing so that the encoder can be driven with a lower driving resistance?

[mightor]

Wouldn't it make more sense to just get one of these:

The HiTechnic angle sensor?

- Xander

[HaWe]

maybe yes, if I had enough sensor ports (and enough money to spend).
But as I wrote above, I have a real lack of sensor ports, I already have to spend one for the Tetrix controller :(
- and so my idea was to utilize 2 motor ports for this issue.

[hassenplug]

matt,
if the encoders you meant can be attached to the motor ports it would be fine - do you have a link (or did I miss it?)
(BTW over all I have 10 motors and more than 20 sensors to be attached...)

Sounds like you just need more NXTs.

Thanks for a good idea. I have a couple spare motors sitting around, I just need to figure out how much needs to be removed, to make it work...

Steve