Mindstorms motor mulitplexer PF power source

[mwareman]

Hello:

I was wondering if it is possible to use the pwer functions 9 volt batter pack with the Mindsensors motor multiplexer? If so, what do I need to do to make it work? I am assuming that I would need to cut and possible modify a PF extension cable? Or, can I use one of the old RCX power cables.

Mike,

[pbenco]

Hello Mike
Go back to good old basic, take a tour on this web site: http://philohome.com/alimservo/alimservo.htm a master as already answer you!
Go to the "Connection with NXTServo", and enjoy!
Hope this help
Ben

[mattallen37]

~pbenco That is not really what I think he wants. He wants to power a 9v motor mux, not the NXTServo.

Why don't you just use the PF battery box normally, and use the outer two wires of an extension cable for the power wires? If you use the outer wires, you don't have to worry about bad polarity.

[mwareman]

Thank you to both Ben and Matt. I had looked at Philo's site but not well enough to find the power functions batterry/cable alterations. Although the notes are for the NXTservo unit the information is useful. I will cut one of my extension cables and use the outer 2 wires to connect to the power connectors on the motor multiplexer. Am I correct that polarity will not be a problem??? Or, do I still have to be careful which wire is connected to which contact and which way the switch on the battery box is moved to??? I guess I can see if I can get my hands on a volt meter and check this out myself.

Again, Thank You for pointing me in the right direction.

Mike,

[philoo]

Am I correct that polarity will not be a problem??? Or, do I still have to be careful which wire is connected to which contact and which way the switch on the battery box is moved to???

Yes, you have to take care of the cable wiring. This image says it all (the wires are directly in front of matching contact)

Fortunately the switch on the battery box has no action on polarity of the two external wires, any position will do.

I guess I can see if I can get my hands on a volt meter and check this out myself.

It's always better to check AGAIN

[doc222]

I powered my nxtmmx's(up to 4 now) at first with a extra battery pack. Now I just tap the NXT and run it all. Oddly enough it works well in my case but say you were running cars and such that are on alot all the etime may not work. Yes batteries run down rather fast but not like most bots need to run long as well. Never browned out yet. This cuts down on the extra weight too.

[ricardocrl]

Just a remark/suggestion.

Even not needing to run a robot for a long time, you should take also into account the heat generated, in the power supply cables, by the total current being consumed. If you have all 4 mux's connected with all 4 motors each running, you will have 16 motors. If each consumes, let's say, 500mAh, you get 8Ah, which is not that little. Avoid using cables too thin for this power supply.

[nxtman3141]

remember me. ok about you question. i would see if a converter cable would work. or else i don't know

[mattallen37]

~ricardocrl
He doesn't use all the motors at the same time, and most decent AA batteries should be able to handle close to that current. Also, FYI, Ah is a measure of storage size, A is the current being drawn.

remember me. ok about you question. i would see if a converter cable would work. or else i don't know

Uh, a converter cable? Did you read the topic? A solution has already been come up with... Also why did you change the title of your post? If that is meant to be directed to 222Doc, I suggest you say so in your message body. I don't think he was asking for help anyhow, he was just saying what he has done with success, as another idea.

[nxtman3141]

ok. you don't need to be all mean.